After recently Burson decided to change the look on their audio products there has been one product that was still left unchanged...well, till now! Yes, Soloist 3X Performance got it’s appearance on the market recently and, besides it’s new shiny polished look and the front LCD, it got the low-noise MCPS regulators inside and dedicated digital volume control. It’s also the first Soloist headamp that has a built-in audio preamplifier and hey...it has both balanced and unbalanced inputs that can be easily selected from the front menu.

This Soloist 3XP sample was sent to me by Burson so I can test it and write down this review, so many thanks to Burson team for this. The package is as expected: double package and thick foam in between, but there's also more foam inside the white box too.


Like the Conductor 3 series, the aluminum "Cool case" design acts as a big heatsink for the big output-stage transistors and the power regulators. Besides its novel look & feel, the Soloist case also offers a very good shielding against any possible outside EMI/RFI interferences.

The “old” internal design has been completely "forgotten" and Burson swapped the big chunky transformer for the new MCPS regulators and a low-noise external power supply. They also installed eight big TO-220 transistors instead of four, like they did in their previous Soloist versions, so power got increased too. Gain has now a 3-stage digital selector, adjustable from the main menu, so another improvement over the 2-stage switch from their older model.


Internal amplifiers are powered via +/-20V rails coming from a couple of powerful MCPS regulators, so a total of 40V RMS is used to help out the output transistors to pump up the audio signal into the headphones. Quite a high voltage for a headphones amplifier, although this is not something new coming from Burson Audio, given the previously released Conductor 3X and Conductor 3 combos.

There are four dual opamps inside that are powered from dedicated +/-15.5V linear regulators, so if you’ll ever think of starting to roll opamps inside Soloist 3XP, then you have plenty of them on the market to roll. Two opamps are used at the input plugs and the other two at the pre-amp XLR outputs from the back. If willing to swap them, just don't forget to double check maximum operating voltage of the opamps you’re willing to install. Most opamps operates well up to +/-16V, including Burson V6 opamps, but some opamps are still having a max. recommended operating voltage of only +/-15V or even lower, to +/-12V, so double check opamp’s datasheet prior to installation inside the Soloist 3XP.



Under the hood we can see several transistors, the three MCPS power regulators, few black and silver ELNA electrolytic capacitors and several shiny ones from the new VZH-series of SMD aluminum capacitors from Lelon, the high-endurance and low-ESR ones, rated to last at least 5.000 hours at 105C (check out
http://www.lelon.com.tw/upload/guides/158200414292.pdf - pag. 102); well, under normal operating conditions (40-50C) these caps should last for several decades.


The relays used in Soloist 3XP are silent and are manufactured by Panasonic, model TQ2-5 ATQ209. There are ten such relays inside and they are used to switch between the inputs and output sources, but also to switch between the three gain settings and also to protect your headphones (power ON delay).

Like the Conductor 3X Reference, inside the Soloist 3XP there are four separated audio amplifiers: two of them are used to drive single-ended headphones (the non-inverted marked with + sign), while all four are operating when driving balanced headphones (both pairs of inverted and non-inverted are working together).



In the output stage we can see eight SMD transistors for each amplifier inside. These are SOT-89-3 case type transistors 2SA1213 (NY) / 2SC2873 (MY) that ensure sufficient voltage to "attack" the final transistors.

The big black transistors from the output stage are the same used in all Burson headphone amplifiers, the well-known Toshiba 2SC5171/2SA1930 complementary NPN/PNP transistors, having a max. power dissipation of 20W each!




Maximum voltage I was able to measure, coming out from the balanced XLR plug just before starting to clip, was 28V RMS @ 600 Ohms; that means 2 x 1.3W, so quite an extreme value.



On the non-balanced jack output the voltage was cut in half to a bit over 14V RMS, under the same circumstances as above. Adding a 30 Ohms resistor I was able to measure a voltage higher than 21V RMS till starting to clip, meaning almost 2x15W of power!



The well-known Neutrik XLR plugs can be seen on both front and back plates, ensuring a good electrical contact for the connected headphones.

The Texas Instruments boost regulators, which are part of the MCPS low-noise design, are followed by linear power regulators, to create clean and stable power rails for the electronics inside.

Soloist’s internal preamplifier is made around the Japanese high-end volume control chip MUSES 72320 that is "buffered" at both input and output by two couple of solid-state V6 Vivid dual opamps. The aduio signal will get unchanged from input to output, via the four opamps and the MUSES volume control chip.


When used strictly as a pre-amp, the audio signal goes into a pair of V6 Vivid opamps, then into the MUSES 72320 volume controller, then it gets to the output pair of V6 Vivid opamps. This way, the connected external amplifier will benefit from the MUSES low noise and distortions, but also from the V6 Vivid sound signature.



The big orange SMD capacitors from top are for decoupling the input source from the MUSES chip, so the amplifier is AC-coupled. Some square-wave tests are a must here, just to check the speed of the amplifier, but also if there are errors or distortions.



Same MUSES chip is also used to control the volume of the headphones amplifier. Switching between pre-amplifier and headphone amplifier modes can be easily done from the LCD menu. You can not use Soloist 3XP as headamp and preamp at the same time; this is also a safety measure, to protect your hearing and headphones when feeding an external amplifier. However, when switching back from pre-amp to head-amp, don’t forget to adjust the gain and volume setting according to the headphones you connect!



The Low/Medium/High gain setting is also used for the pre-amplifier, not just for the head-amp, so the gain setting you choose will increase or decrease the output sound on both pre-amp and head-amp plugs. For the pre-amp feature I would recommend the High gain setting and the volume setting should not pass the 75 marking to not overload the external amplifier connected.




The powerful Soloist can easily drive up to three pairs of headphones at the same time, one connected to the balanced XLR plug and the other two connected to the 6.3mm and 3.5mm jacks. However, you should take care of the final impedance that results after connecting two or three pairs of headphones at once, because getting below 16 Ohms might not be recommended for the amplifier. Soloist 3XP can not adjust volume for each of the three headphones plugs, so same amount of power will be applied (actually double for the 4-pin XLR), so it might be challenging in getting the desired power for all the three headsets connected.



The volume can be easily adjusted via the front-right rotary knob and the output level can be seen on the front LCD. Internally, there is no carbon potentiometer, but a resistance ladder circuit inside the MUSES 72320 chip that takes care of modifying the output volume with a very good precision, 120dB channel separation and minimum channel imbalance (unlike the older potentiometers that used to have a bad reputation when volume was approaching the minimum scale).



The Soloist design has V6 opamps DNA inside. I am referring to the eight SMD transistors from each internal amplifier and to the blue variable resistors (V6 has small white variable resistors inside) used to adjust the output DC-voltage. Try not to touch or adjust these blue resistors, as there will be no gain in the audio quality. These are not for adjusting the current bias into class-A! The current bias can not be adjusted, as it was already calculated and implemented correctly by the manufacturer.



The output DC-voltage is already pre-adjusted by Burson to a minimal value. After a couple of minutes of warm-up, I was able to measure values between +/-1 mV and +/-5 mV of DC, so a respectable low value indeed. However, in case you intend to swap the default opamps inside, don’t forget to measure the DC on both jack and XLR plugs before connecting headphones and adjust the blue variable resistors ONLY if the DC is higher than +/-25 mV per channel (or wait more time to warm-up or swap back the opamps with the originals from Burson).

Given the very high amount of power and an output impedance pretty close to zero, Soloist 3XP will drive any dynamic or planar headphone connected, even the very hard to drive HE-5 and HE-6 from Hifiman.

I’ve also tested it with 127dB/V KZ AS10 and ZSX IEMs on the jack output and when Low-gain was used the sound was perfect and volume knob could be raised to 30-40 without getting worried of overpowering them. In a completely silent room, at night, a slight faint of hiss noise could be heard, but only if no music was playing and room was dead-silent. I had it compared side-by-side with Conductor 3XR and I found that the hiss noise on the Soloist 3XP is almost non-existent. With headphones having a lower sensitivity I couldn’t hear any hiss, no matter how hard I tried to.

Worth mentioning that the XLR plug is pushing twice the output power compared with the jack plugs, so the background noise will also get doubled too. However, the most sensitive “over the head” headphone I have is the AKG K550 with balanced cable and I’ve heard no background noise at all coming from them, when connected to the 4-pin XLR from Soloist 3XP, even if these cans are rated to about 115dB/V SPL (measured here).

I've tested this Soloist with LCD-2F, Hifiman HE-560, AKG K701, AKG K550, Audio Technica M30x and KZ IEMs and I had perfect match with each one of these cans. Finding the right gain setting was done starting from the Low gain, then switching to Medium or High gain if needed (only to HE-560 I could use the High gain, otherwise the Low or Mid were used). Half of the power is gradually delivered from 0 to about 85 reading on the LCD, then the boost comes up and unleashes the beast with the remaining power. That means that switching from a reading of 20 to a reading of 40 will not kill your ears, instead it will be a gentle logarithmic level increase.

Hifiman HE-560 (unbalanced & balanced), 100 dB/V:
- There are rather hard to drive planars, needing more current to be driven properly, unlike most of the dynamic headphones. Given the "oversized" output stage from inside the Soloist 3X, driving Hifiman planars was piece a cake and also an expected delight. The fast and powerful bass sounded clean, precise and even when cranking up the volume really high there was no sign of any distortion. The level of details was very good, like the rest of the Conductor 3 series devices, with a perfect channel separation and soundstage.

Fostex T50RP-mk3 (unbalanced), 103 dB/V:
- Like the above planars, bass was striking perfectly and sound was neutral and somehow warmish. I feel that I could listen for several hours without fatiguing my hearing, probably due to the low distortion amplifier inside or maybe due to the neutral but somehow warm sound the Soloist 3XP pushes into the headphones.

Beyerdynamic DT-880 600 Ohms (unbalanced & balanced), 96 dB/V:
- Most headamps will not drive them properly, due to the rather high voltage they need to be amped, but with the new Soloist this won't be a problem. They sounded right, brighter but with clear notes of bass and I was able to catch every little detail from the music. Of course, Low-gain setting is not for these cans, given their 600 Ohms impedance, so I needed to choose the Medium-gain when going balanced and even the High-gain when using the unbalanced cable (although it was fine with the Medium-gain too, but I want it to hear the Highest gain too).

Audeze LCD-2F (unbalanced & balanced), 105.5 dB/V:
- These are rather sensitive planars, so definitely not a problem in driving them with most headphones amplifiers, but they still need a decent amount of power to be properly driven. However, I was able to use both Low-gain and Mid-gain with these cans and listening to the music was a pleasure. It was a perfect match with the Soloist, on both XLR and jack outputs, and I totally recommend this amplifier for driving Audeze or Hifiman planars. I got an incredible amount of details and very fast and precise bass, without any signs of hiss.

AKG K550 (balanced & unbalanced), 117.8 db/V:
- These are neutral sounding headphones with a decent soundstage and very good bass reproduction and this is exactly how I perceived them with this new Soloist headamp. Given their high sensitivity I was expecting to hear a little bit of hiss coming out of the Soloist, but instead I got no background noise at all, not even when using the balanced 4-pin XLR plug. Of course, I've used the lowest gain setting to drive them and I never felt that volume should pass the 50 marking. These headphones sounded better than ever, despite their high sensitivity, so this is quite an accomplishment from Burson, given the extreme power rating Soloist 3XP has; I never thought such a powerful headamp could drive sensitive cans without hiss noise and without getting worried to not kill your ears while moving the volume knob.

AKG K701 (balanced & unbalanced), 102-104 db/V:
- Considered to be hard to drive dynamic cans, due to their below average sensitivity and the 62 Ohms impedance, I never felt the Soloist struggling in driving them at all. Instead, I've heard one of the most accurate bass ever coming out from K701, with a fast kick and a very detailed presentation. For some folks the increased soundstage of these headphones might be overwhelming, but for me is like a treat.

KZ ZSX (24 Ohms IEMs) & KZ AS10 (22 Ohms IEMs), about 127-130dB/V sensitivity:
- Really sensitive IEMs, so I only use them when I need to test for the background noise. I couldn't use them with Mid and High gain settings, due to the audible hiss, but also to protect my hearing, but when switching to Low-gain most of the hiss noise disappeared and only slight of it remained, but definitely not something to distract anyone. The hiss was barely heard and I was doing my critical listening inside a quiet bedroom at night. Comparing the Soloist side by side with the Conductor 3XR, given the darker background of the Soloist 3XP, I consider it a better match for sensitive headphones. Also, the KZ ZSX had an impeccable bass response, quite pleasant to find out that I could pair such sensitive IEMs with such a powerful headamp.

AudioTechnica ATH-M30X (unbalanced), 115 dB/V:
- I used these for monitoring only, connected to my Focusrite studio card, due their rather high sensitivity and accuracy of voice reproduction. Of course, no noise could be heard coming from the Soloist 3XP and both female and male voices were perfectly sounding.

In an A/B test done with Soloist 3XP Performance vs. Conductor 3X Reference I was unable to tell which one sounds different, no matter how much I struggled. Probably this was due to the very similar construction in both amplification stages and power supply as well. Worth mentioning that one C3XR from the below stack was having NJM5532D, while the other two devices were having V6 Vivid inside. I had also hard times in finding the C3XR with NJM5532D in a "blind" A/B test, so even with the cheap and good 5532 opamps these devices sound really good.


Referring strictly at the headphones amplifiers, the only slight advantages the Soloist 3XP might have against the Conductor 3XR would be the lower background noise on both XLR and jack outputs, the simpler construction of the internal pre-amplifier, but also the 3-states gain adjust.

Soloist's warranty is 2 + 1 years, meaning that you get a default 2-years warranty and, if you register it online, then you will get an additional year of warranty. This is a good thing, especially that Burson claims and warranty department is very responsive.

Manufacturer link: https://www.bursonaudio.com/products/soloist-3x-performance/.

The design and the “Cool case” concept vs. former “The Vault”:

By looking 10 years back in time to Burson Audio’s products (Conductor HA160/D, Conductor V1 / V2 / V2+, Timekeeper, Soloist SL) designed to please customers as Hi-Fi equipment for desk/office use, we do see lot of similitudes in how they look: big, heavy, powerful, imposing, shiny & expensive look, audiophile-like quality at first sight. Couple of years ago Burson Audio introduces smaller and lighter desk/office audio equipment like Play/Playmate/Swing/Fun/Bang, Air addressed to customers willing to install these in their own desktop computers or simply deployed on their desks without occupying much space with similar audio quality like their previous designs.

Now I’m looking to latest Burson’s high-end products, Conductor 3 Ref & 3 X, and I realize that their look is way different than the previous versions of Conductor. We now have a smaller case, a bit shaped, still shiny but shades are now space-gray, like the newer MacBooks.


I do love the newly designed case, but given that I’m also old-fashion and quite reticent to new designs, it took me a while to understand why Burson changed the appearance of the previous corner-shaped polished aluminium enclosures (aka “The Vault”) in their latest high-end models. Given they recently swapped the big power supplies with one or two toroid transformers inside (bulky and heavy, about 1Kg each) with their newly developed MCPS technology, now the max. height of the Conductor could be much lower, because transformers were the tallest component from in there, hence the smaller and lighter case of C3Ref and C3X. Worth mentioning that the former Conductor V2+ has a weight of 7Kg, while C3 barely gets to 5Kg.


Also, to improve heat dissipation inside the case with about 300% over their previous TOTL CV2+, they added wrinkles on both top and bottom parts of C3’s case, in a manner that is more good looking and way more thermally efficient. There are no visible screws and no sharp corners, so Conductor 3 looks pretty much like a uni-body design, making it much more appealing when seen and touched live than seen in the pictures.



The front plate contains a shiny slick rotary knob on the right, the big OLED screen and the 4 switches with explanatory icons on top for choosing inputs/outputs/settings are located in the middle, microphone and headphones output sockets on the left side. The power switch is located on left side as well, Their arrangement is straight forward and needs no explanation.

All the analogue and digital inputs and outputs are located on the backside, same as the power socket and BlueTooth antenna.


A bit about the MCPS power supply:

A very bold and inspiring innovation designed by Burson Audio is their Max Current Power Supply technology: https://www.bursonaudio.com/about-us/max-current-power-supply/. No other manufacturer has this technology yet and Burson has been pioneering this new technology since 2017, when the first version of PLAY appeared on the market (Head-fi thread here: https://www.head-fi.org/threads/new-burson-audio-play-amp-dac-2w-16ohm-op-amp-rollers-dream.860882/). To cite them, “Since the main power has a 50-60 Hz working frequency, [...] this frequency is within human hearing hence extremely noisy. [...] The Burson MCPS increases the working frequency to 170khz. Any noise at this frequency is well above the human hearing threshold of 20khz. The result is a pitch black sound-stage critical for micro-details to shine through”.

Most of audio equipment is injecting mains hum (a frequency of 50-60 Hz), to some extend, depending on the shielding used to the transformer, might be audible, might be not, but in any case this mains hum is measurable with proper gear. Burson’s vision is that removal of the big toroid transformers will completely remove any possible mains hum, while lowering the total weight of the device and also increasing the efficiency of the power supply.

While a regular power supply based on transformers then followed by bridge rectifiers, big capacitors and linear regulators has a power efficiency of about 40%, Burson’s transformer-less MCPS has about double efficiency, hence will consume less energy and be more environment friendly. Of course, the heat dissipation will be lower with MCPS vs. the traditional designs.

The C3X DAC/pre-amp.headamp combo is using en external 150W low-noise power supply (measured ripple & noise of only 0.01%), but internally we can find several Texas Instruments boost-regulators, but also TI and ST linear regulators as well.



The analogue stages from C3X are getting the power from dedicated power regulators, they’re not sharing the same supply with the digital stages. I was able to count no less than 11 big linear regulators (LM317/LM337, LM1085, LM7805), as well as 5 low-noise switching regulators (TPS54560), without including the small ones from around the DAC chips or from the USB transport board (AMS1117 etc.). At the input power jack we can find a P-Channel MOSFET IRF4905S, most likely used as buck-converter.

The 4 dual op-amps (2 in I/V and 2 in LPF) are powered by dedicated linear regulators delivering a low noise and free of ripple +/-15.3V, while the beefy output stage is powered by +/-20V delivered from the low-noise boost-regulators (measured ripple & noise of about 400uV RMS, so a 0.002% of ripple). Each of the 4 amplifier-rails are having several bypass capacitors nearby the output stage transistors, hence the maximum current is instantly delivered into the headphones.


I was able to count around 125 electrolytic ELNA capacitors, although the small SMD ones from the motherboard are probably counting more than that, so quite an astonishing decoupling technique by choosing so many capacitors/inch for decoupling instead of going with big ones. This is definitely decreasing the noise coming from the power supply and provides a very clean output to the XLR/jack plugs.


Details about the Digital and Analogue Parts Inside

The DAC is fully balanced, like the SWING, and is created around two ES9038Q2M chips (http://file2.dzsc.com/product/18/05/25/829029_170233543.pdf), each one having a SNR of 129dB. The I/V and LPF stages are created around the SS V6 Vivid op-amps, well-known for bringing all the micro-detailes from the music into the headphones. However, some C3X versions might have different opamps inside (e.g.: SS V6 Classic or JRC5532D), but this won’t affect the performance of the device, although sound perception might differ a bit in soundstage presentation and details retrieval.




The 44-pin ALTERA EPM3064A chip is a CMOS EEPROM–based programmable logic device (PLD, see https://en.wikipedia.org/wiki/Programmable_logic_device for details) where all the programming software is loaded, so that takes care of how C3X will operate properly.



The headphones amplifier is fully balanced as well, so it actually contains four distinct amplifiers inside, two per each channel (for inverted and non-inverted signal). However, in unbalanced operation (when driving headphones via the 6.3 mm jack) only two of these amplifiers are used. The amplifier itself is created around 40 transistors Toshiba 2SA970/2SC2240 (5 pairs per each amplifier rail) in pre-amplification stage and 8 big transistors Toshiba 2SA1930/2SC5171 working in Class-A in the output buffer (2 per each amplifier rail).

Output stage is created around the powerful Toshiba 2SA1930/2SC5171 complementary bi-polar transistors, two pairs per channel when used in balanced mode and twp pairs per channel when working in unbalanced mode. Each single output transistors can sustain a max. theoretical power of 20 Watts, so driving headphones will be piece a cake for them, including the extreme power-hungry planar headphones Hifiman HE-6 that will be driven by C3X to an of 118dB! All the output transistors are connected to the bottom aluminium base via normal screws, so heat dissipation from the output stage is done on the bottom.

The jack and XLR output plugs are getting audio in parallel, so you can listen to both balanced and unbalanced headphones at the same time, as long as you're comfortable with one volume setting for both. Also, don't forget to pause the playing while plugging/unplugging the unbalanced headphones, due to the fact that every stereo jack plug will create a short-circuit when inserted or ejected! This is not happening on mono jack, nor to XLR plugs.

Headphones are protected by a dedicated relay, so there will be no thump when powering up the device, although Burson recommends not keeping headphones plugged in while powering on the device. A small “thump” might be heard if C3X gets powered ON with headphones connected, but this is normal until the op-amps will get warmed-up. However, if a high level of DC will occur, the protection will kick in fast

C3X has inside one of the most powerful headphones amplifier ever built and, as an all-in-one combo (with DAC, pre-amp and BT streaming), is probably the most powerful in the world at this moment. Some data from my own measurements below:

Power rating measured (W) / Load resistance:
13.5W/ 15 Ohms (14.2V RMS)
13.5W/ 30 Ohms (20.1V RMS)
13.5W/ 50 Ohms (26V RMS)
7.5W/100 Ohms (27V RMS)
2.5W/300 Ohms (27.5V RMS)
1.25W/600 Ohms (27.5V RMS)






The streaming playback is looking very similar with the original USB playback, although we can notice the energy from the trebles starting to fade out gently after getting over 17.5KHz (explained why here)
An uncommon but interesting approach I see in the way the pre-amp volume is done, as there is no analogue potentiometer inside, just the digital rotary knob tied-up to the built-in 32-bit volume from the two ESS DAC chips. So Burson's R&D tied-up the XLR inputs to a 123dB SNR ADC chip: AK5394AVS (https://www.es.co.th/Schemetic/PDF/AK5394A.PDF). The digital signals are getting into the 32-bit volume control from the ES9038 chips, so there will be no bits truncation that will affect the sound and no noise added. This is probably the only pre-amp in the world using this concept to control the volume of the analogue inputs, so quite an achievement.




The BlueTooth audio is done around the "Premium tier" Qualcomm® CSR8675 chip (https://www.qualcomm.com/system/fil...-audio-flash-product-brief_87-ce852-1-b_0.pdf). This chip delivers 24-bit/192KHz audio over Bluetooth and aptX HD as well. Linking my cellphone (iPhone 8 Plus) took about 2 seconds after I initially chose the BT output from the C3X LCD menu.



Headphones DC protection circuitry is done around the C1237HA chip and two relays, one for each output socket (6.3mm jack and the 4-pin XLR).

There's a low-power USB hub controller on the USB module, GL850G connected to onboard dedicated 12 MHz crystal. This has an 8-bit RISC processor inside that quickly responds to USB host requests. This USB hub should minimize PC's USB host ripple and noise and also to power the USB chip via the internal low-noise regulators.

The USB transporter is a XMOS XU-208 chip from the latest generation on the market, xCORE-200: XU208-256-TQ64. This is a 32-bit chip powered by 8 x real-time logical cores running at a frequency of 500 MHz. It gets the clock from the onboard 22 MHz and 24 MHz oscillators.



Microphone mono 3.5 mm jack is connected to the CM6327A A/D converter chip that converts the analogue sound received by the microphone socket into the digital samples. This has a max. of 48KHz Sampling Rate and a dynamic range of 96dB.



Headphones Matching - Sound Quality and Idling Noise:

The internal gain of the C3X is higher than CV2+'s gain: CV2+ with a volume setting of 99% was as loud as C3X with a volume setting of 87%. Due to the higher gain, some slight of hiss-noise may be heard when using very sensitive headphones. However, on the 6.3mm unbalanced jack socket, the background noise on C3X is a bit lower that on the CV2+.

Pairing the C3X with high sensitive headphones might not be a very wise thing to do, especially if speaking about 8-16 Ohms IEMs, due to their very high sensitivity. With my extremely sensitive 130dB/V KZ AS10 IEM's I was able to hear some hiss-noise, although these headphones are designed for portable use anyway.

Now comparing the output levels with Audeze LCD-2F between the two headphones outputs XLR/jack, there would be about the same levels to my ears when using a volume setting of:

• C3X - XLR vol. setting of 25
• C3X - Jack vol. setting of 40

Worth mentioning that volume control is somehow logarithmic in the beginning and at the end, but goes linear between volume settings of 40...80. For example, at lower settings, between 1-40, the volume barely raises, instead at a level of 80 power gets twice as much than at a level of 40 and at 100 there will be twice as much power as at 80 and four times more power than at 40.


Below is a summary of sound impressions after listening to different headphones::

Headphones, Sensitivity, Impression

AKG K701 (balanced & unbalanced), 105 dB/V:
- Rather hard to drive headphones, but the “endless” power of the C3X drove them easily and with great authority. I found a very good pairing with all songs I've tested, a big soundstage, a big sound.

Audeze LCD-2F (balanced & unbalanced), 112.5 dB/V:
- Planar technology, but not so hard to drive. I was able to get lot of details and a huge scene with C3X and LCD-2F, probably due to the Solid-State V6 Vivid op-amps and to the discrete output stage too. I totally love the sound coming out of LCD-2F and I so understand now why Burson recommends pairing their amp with planar headphones; probably this is why they had the C3X + LCD3 promo recently.

Hifiman HE-560 (unbalanced & balanced), 100 dB/V (103 dB/V per Innerfidelity):
- Not easy to drive planars, actually these require quite a good amount of power and current to be driven properly. The beefy output stage of C3X drove these planars with ease and bass was striking fast and powerful, without any signs of congestion. I pushed the volume insanely high for few seconds and the low-end bass become more powerful than ever, almost like a subwoofer pumping into my chest.

Fostex T50RP-mk3 (unbalanced), 103 dB/V:
- Clean sounding, very neutral, great for monitoring for sure. Low-powered amps will never drive well these planar headphones, of course, but not the case of C3X.

Beyerdynamic DT-880 600 Ohms (unbalanced), 96 dB/V:
- Very detailed headphones, a bit on the bright side, so I had them tested with V6 Classic and the sound was very detailed, pleasant without being sibilant in the top end (when using V6 Vivid some slight sibilance appears on top end). Despite that these cans are lacking sub-bass per design, when pushing C3X’s volume higher, I was able to get a pretty nice and fast bass, although not much of the impact per their design. The clarity was definitely top-notch, so probably to many details if paired with V6 Vivid. The amount of power C3X amplifier is extreme, on both XLR or jack headphones outputs. I wasn’t even able to push it to half of its max. power with these high-impedance 600 Ohms headphones, so I don’t think there is a headphone out there that C3X will struggle to drive it, not even Hifiman HE-6.

GRADO SR60i (unbalanced), 115 dB/V:
- Not a SR60 fan myself, due to their brightness and lack of sub-bass, especially when paired with SS V6 Vivid, but swapping opamps from SS V6 Vivid to SS V6 Classic will make them sound more “comfortable” and relaxed to my ears, with o larger scene than regular 5532 op-amps.

AKG K550 (balanced & unbalanced), 117.8 db/V:
- Very sensitive headphones, although I got no background noise when using the 6.3mm jack socket. These are made for portable devices, so with volume at 10 in high-gain my ears were already flooded with music. Soundstage was higher than usual, especially when using the balanced 4-pin XLR output, although between tracks a tiny hiss could be heard due to headphones higher sensitivity.

AudioTechnica ATH-M30X (unbalanced), 115 dB/V:
- I use them for monitoring purposes and I only tested them with C3X to check for background noise, but it simply wasn’t there, despite their rather high 115dB/V sensitivity.

Superlux HD381F (16-Ohms IEM), 121dB/V:
- Extremely sensitive IEMs, with only 1 mW applied the music will get to an SPL of 100 dB, so some hiss noise is to be expected from such a powerful amplifier. However, in Low-Gain I was able to find the correct volume level to get from these IEMs a striking and pleasant bass, although the trebles were nicer and softer with V6 Classic vs. the V6 Vivid (most likely due to the headphones freq. response on the trebles).

KZ ZSX (24 Ohms IEMs) & KZ AS10 (22 Ohms IEMs), about 130dB/V:
- Extremely sensitive IEMs, even in low-gain mode the output power of C3X is rather high, also background noise is present during the tracks. By using iFi EarBuddy the C3X becomes absolutely silent with these IEMs, so totally recommended with such powerful headphone amplifiers. The sound is a bliss, totally unexpected, given that C3X was not designed to drive such sensitive headphones. Bass is striking perfectly into my ears, so that’s a good sign that the overall damping factor is low enough to pair C3X+EarBuddy with 22 Ohms headphones, which is a very good thing.


Beats Solo 2 (unbalanced), 118 dB/V:
- Very sensitive dynamic headphones, also very clear sounding and neutral as well. The bass strikes with lot of force, but not boomy at all and the extra details of the V6 solid-state op-amps, even if the scene of these headphones is not the largest possible. In a quiet bedroom at night I felt a faint hiss noise between tracks, although during the day I couldn’t hear it. However, these headphones are designed for use with portable audio gear only.

Superlux HD-662 EVO, 113 dB/V:
- Cheap and balanced dynamic headphones, although a bit harsh on top with some rock songs. Very easy to drive, with a tiny amount of power applied by C3X, these cans were sounded full of bass and with a good scene. I couldn't hear any hiss-noise coming from C3X with these cans.


The “Lavish Musical Experience” Sound:

C3X excels with power-hungry headphones, especially with orthodynamic ones (aka planars). Its huge amount of power is indeed lavish to the listener and combined with the preferred DAC’s digital filter this combo might be an “end-game” for many customers.

While the unbalanced jack output is a very good pair for most headphones, when going balanced the power increases and also the scene gets wider and sound gets more peaceful and pleasant (some might call it a bit warmer). Bass seems to strike a bit deeper and more powerful when going balanced, at least when using planars, probably due to the way balanced driving works or to the different cables used.

BURSON C3X is a very detailed and revealing DAC/headamp combo and with Audeze LCD-2F connected to XLR balanced-out, while listening to DSD256 (11Mhz) and DSD512 (22MHz) tracks, I could actually hear concert hall’s background noise from the beginning of each track and between the piano notes. C3X will forgive no hiss and no rustle from the tracks and in case you haven't heard before when vocals will inhale/exhale or murmur of their lips, now you will, so prepare for an increased clarity and a boost in details retrieval.


[Later edit] Some of the artists I've listened to test Burson C3X:
Cardi B., Norah Jones, Cheloo, Faydee, Antonia, Adelle, Ed Sheraan, Lil Nas X, Irina Rimes, Zdob si Zdub, Vinka, Minelli, Fly Project, INNA, The Black Eyed Peas, French Montana, Jonas Brothers (I'm only writing here about the Dance music, although there are several others in the Jazz, Blues and Classics areas).

In "Clandestina - Filv" bass was striking like a madness, full of authority and without any trace of distortion. The huge power reserve of the built-in discrete amplifier has definitely something to say here. This song contains a very good low-end to test the amplifier, also the headphones. Worth mentioning that even my 8-Ohms speakers were perfectly driving the low-end of this song (totally not recommended to connect speakers with C3X, so don't do like me!!!). Same impact on the low-end I felt it while listening in songs like Old Town Road (Remix) - Lil Nas X feat. Billy Ray Cyrus, Trop beau - Crisologo, Trika Trika - Faydee, Antonia.

I'm also adding to this review that C3X & C3R are based on a modular design, the motherboard containing more parts on top, like the USB XMOS transport card, the Bluetooth card, the front plate module with the rotary knob and headphones sockets, but also the back plate with the XLR/RCA plugs. This is a good thing, because you never know when an updated card will appear as an upgrade on Burson's shop website, but this is also helpful in case of RMA, due to the fact that shipping abroad 1 Kg is way cheaper than shipping 6-7 Kg.


PROs:

• One of the most powerful headphones amplifiers ever built, on both balanced and unbalanced outputs.
• Able to play all kind of 24 & 32-bit PCM files, but also DSD x64, x128, x256 formats natively via the custom-made Thesycon ASIO driver provided, without any pops when switching between the source formats (tested under Windows, Linux and MacOS with Foobar, jRiver, VOX, VLC, Rythmbox, Clementine players).
• Needs no drivers for Linux, MacOS or Windows 10, also it is recommended to install Burson’s driver under Windows for native DSD and low-latency playback.
• A real "detail retrieving" Class-A audio device, especially when using solid-state V6 op-amps.
• Great soundstage and channel separation, especially when going balanced.
• A complete DAC/headamp/pre-amp/streaming audio solution with a very powerful, flat and neutral sound.
• Trebles and bass extensions are easily reaching the edges of audible octaves, due to the direct-coupled amplifier and headphones (no caps in signal path).
• No opamps in audio signal path when using Burson SS V6 transistorized DIP8 amplifiers, designed especially for audio use.
• Smaller size and weight, lower temperature and lack of transformer hum due to the improved transformer-less MCPS design (low noise switching regulators followed by linear regulators).
• Ability to be positioned vertically while LCD can be also rotated from pressing a frontal switch.
• Several Digital filters to choose from will help in getting the desired output sound (pre/post ringing for impulse response etc.).
• Having two digital gain settings is a plus, because it protects our hearing when using sensitive headphones, although it will not lower the background noise when using very sensitive IEM’s (just use an EarBuddy for these IEMs).

CONs:

• Gain is a bit higher than expected, especially when going balanced, so with very sensitive headphones some background noise might be audible. For headphones having a higher sensitivity (>115 dB/V SPL in single-ended, >100 dB/V SPL in balanced operation; if needed, use https://reference-audio-analyzer.pro/en/dbv-dbmw.php for dB/mW to dB/V conversion) you might want to add an iFi EarBuddy or ieMatch.

PACKAGING:

Like usually, Burson Audio takes perfect care on ensuring the best protection for their audio device during the transportation. PLAYMATE was nicely packed into a double-case package, the inner case being filled with protective foam inside.

The power supply and the accessories pack (6.3mm jack, torx screwdriver, inside computer plugs, RCA-RCA stereo cable) are packed into different smaller cases.

I will not upload any package pics here, as other headfiers already did that, but simply put: a well-made sturdy package the doesn’t weights a lot.


LOOK & FEEL:

PLAYMATE looks very good, with it’s silver shiny aluminium case. I always felt that black anodised aluminium it’s the perfect “color” for my taste, but now I realised that PLAYMATE’s case looks better in shiny-silver than in black.

The look, dimensions and weight are very similar with the former PLAY combo, just a new small button and the nice LCD on front, also the optical input on the backside.

Design is simple and straight forward, attached pictures should be self-explaining. Just to realise its size and its beautiful look, I placed it on top of my Conductor Virtuoso 2+.





FUNCTIONALITY:

I was able to use the default operating system drivers on Windows 10 and Mac OS Sierra/High Sierra/Mojave, but I've also used the driver provided by Burson as well. I had no issue with installing drivers and process went flawless. Actually, I had installed on the same computer PLAY, PLAYMATE and Conductor, all playing at the same time by using different drivers and audio players and not even a hiccup or latency were observed on none of the three DACs, no matter if I played from Wi-Fi network or from the local disc, ASIO, WASAPI or Kernel Streaming. This is a very good thing, because good drivers and operating stability is a very important aspect from an audio equipment.

All type of files I had in my computers worked flawless: FLAC, ALAC, DSD64/128/256 (native decoding) and, of course, MP3. Not a hiccup or latency while seeking through songs, no matter I was using Burson ASIO, ASIO4ALL or WASAPI, under both Foobar and jRiver applications.

The volume can be adjusted from the big rotary knob in 100 levels. Pressing it will also make PLAYMATE to mute. The rotary knob also alters RCA output volume, not just the headphones out, making PLAYMATE to work as a preamp.

Input sources are selected from the main menu, by pressing the small rounded button from the front panel, on the right of the rotary knob. From the same button we can switch from RCA to Headphones output, but we can also change the digital filter and all other setting from the main menu, per the datasheet.

The included 6.3mm to 3.5mm jack adapter will help in connecting all kind of non-balanced headphones and the RCA-RCA cable, of a very good quality, will connect the PLAYMATE combo to an external power or headphones amplifier. The front USB-C could be used to connect mobile devices, via dedicated OTG cables. The front 3.5mm jack can be used to connect an external microphone, so PLAYMATE can be actually used inside or outside your desktop computer’s case and having the same functionalities as a computer soundcard, just a better sound quality and a much more powerful built-in amplifier.

In conjunction with Burson BANG and a low-noise computer power supply, PLAYMATE can make your desktop computer an all-in-one audiophile solution, a space saving solution as well. All you need to take care of is a really good power supply, some space left under the BANG for cooling and a very good “positive pressure” ventilation inside computer’s case.


INTERNAL PARTS, BUILD QUALITY

First of all I’d like to say that I’m thrilled when I see no opamps and no capacitors in signal path. Of course, I’m referring to PLAYMATE versions with solid-state “opamps” inside, like V5 or V6. When opamps are so cheap you need to have lot of guts to do that, and all of these just to get the best output sound. Also, lacking capacitors from signal path makes a frequency flat combo, with not even one “drop” of roll-off on the low-end (10-20 Hz bass)


PLAYMATE share a similar USB transport card with PLAY: identical XMOS U208 chip, the USB hub chip powered from the internal low-noise (LT1085) +5V linear regulator and not from computer's USB port. I see two added LEDs that show us the state of the USB transport card: one LED lights up when connected to th USB port and the other LED when music starts playing. firmware can be future upgradable via the 3 volts 4Mb 25P40VP serial flash memory: M25P40 Serial Flash Embedded Memory - Micron Technology, Inc.



There’s an additional USB hub on the USB transport card: GL850G, connected to onboard dedicated 12 MHz crystal. This has an 8-bit RISC processor inside that quickly responds to USB host requests. This USB hub should minimize PC's USB host ripple and noise and also to power the USB chip via the internal low-noise regulators.


The USB transporter is a XMOS XU-208 chip from the latest generation on the market, xCORE-200: XU208-256-TQ64. This is a 32-bit chip powered by 8 x real-time logical cores running at a frequency of 500 MHz. It gets the clock from the onboard 22 MHz and 24 MHz oscillators.

The chip responsible with the digital to analogue decoding is ES9038C2M, that is getting the clock from the onboard 100 MHz oscillator. This is a high-performance 32-bit, 2-channel audio D/A converter able to natively decode both PCM and DSD formats with a dynamic noise up to 129dB and a THD+N of -120dB. It has also a 32-bit digital volume control and an internal DSP with built-in "click-free" soft mute feature to suppress any possible popups when switching between PCM and DSD or vice-versa. The DAC chip is powered from a dedicated LT1085 low-dropout & low-noise linear regulator, then gets lowered again to +3.3V by the ultra low-noise CMOS linear regulators ADP150 made by Analog Devices (9uV RMS across 10 Hz to 100 KHz).

Microphone mono 3.5 mm jack is connected to the HS-100B chip which acts as Analog-to-Digital converter in this scenario. This is a 48K / 44.1KHz Sampling Rate Analog to Digital converter that convert signal getting from the microphone to digital PC format. It actually measures very well for a input source for microphone:


POWER SUPPLY:

PLAYMATE has powerful 65W/12V low-noise SMPS power adapter, similar in size with a laptop adapter. Even the power plug might be similar with one from a laptop’s power adapter, we should never try to connect a laptop adapter into the PLAYMATE, because of different voltages involved (laptops work around 19-22V)!


There are five low-noise boost-regulators inside the PLAYMATE, dedicated for digital and analogue electronic circuits inside: XL6007 for the positive rails and TPS5430 for the negative rails. Separating digital and analogue power rails will lower the background noise, increase the dynamics and minimize interference from the digital parts, like volume control or relays coils. Also, worth mentioning that the DAC chip and the USB transport are powered from two dedicated linear low-noise regulators.


AMPLIFIER:

Output stage is created around the powerful Toshiba 2SA1930/2SC5171 complementary bi-polar transistors, two pairs for each channel. The Class-A biasing is done via Toshiba 2SA1930/2SC5171 transistors, kept tight together to have same temperature. The output transistors are having an absolute maximum operating power of 20 Watts each for heatsink temperature lower than 25C, so driving headphones will be piece a cake for them, as long as we’re not speaking about headphones needing more than 2W/32 Ohms. All the output transistors are connected to the bottom aluminium base via normal screws, so heat dissipation from the output stage is done on the bottom. Output DC-voltage is very low and it’s backed-up by a dedicated protection circuit (UPC1237HA) on the output jack to protect the headphones if wrong op-amps are installed/swapped or in case of defects that could possible inject DC-voltage on outputs. However, keep in mind to not connect/disconnect your headphones when music is playing! This could cause damage to the inside amplifier (same applies to all stereo jack plugs).


Polymer polarised long life and high quality Japanese ELNA capacitors and metalized Dale resistors can be seen across the board, to further minimize the output noise on signal path, but also to further lower power AC ripple.


The internal gain switchable from the main menu via the rotary knob and the LCD panel can be adjusted in two positions: Low and High.

On the Headphones-Out:
- High-Gain has a max. output voltage of 10V RMS
- Low-Gain the max. voltage will be 1.05V RMS

For the RCA plugs:
- High-Gain has an output of 5.3V RMS
- Low-Gain the max. output voltage will be 530mV RMS

Given the high RMS voltage for the High-Gain on the RCA plugs, this makes the PLAYMATE having an outstanding dynamic range for a non-balanced audio equipment, of course, if your amplifier is able to accept such a high input voltage of 5.3V RMS. Otherwise, please stick with a volume setting of 82% on the High-Gain, where the 2V RMS will be achieved (tested with 1KHz 0dB sinewave).

Notice: If unsure of the max. input voltage of your external amplifier, just stick to a max. of 82% volume setting when connecting an external amplifier, just to be sure you'll not drive your amplifier into clipping or damage its input stage! Of course, when switching PLAYMATE from Pre-Out to Headphones-Output, ensure that no headphones are connected, because 82% volume setting will most likely damage your ears and headphones! So first lower the volume, then switch from Pre-Out to Headphones-Out, for your own safety.

Headphones, but also the output stage transistors are protected by an output relay that gets activated in case of high-DC voltage (usually if a defect appears). If something gets defective inside, the relay will not let any DC-voltage passing onto the headphones.


HOW DOES IT SOUNDS?

After few dozens of hours of burn-in (not a must, but still recommended) I did a listening test, because I want it to hear how the bass sounds on the new PLAYMATE, compared with PLAY and Conductor Virtuoso 2+ (CV2+). After all, these three audio devices are sharing a similar output stage done by eight identical powerful transistors, only differences consisting in higher voltage rails provided by a high-end PSU and a dedicated preamplifier with digital volume control inside the CV2+. With my A/B testing device, after a careful output power match done with my oscilloscope, it was difficult to impossible to find a clear winner between the three devices. I was alternating Hifiman HE-560 and Fostex T50RP-mk3 planars and tried to identify the best low-end impact and quality, but I couldn't; it was simply tie, because all the three were sounding the same to my ears, with great impact, lot of kick, exactly like a subwoofer does when it's added into a room.

Beside my regular test tracks from Chesky and several other Jazz songs (with lot of micro-details inside), I had tested PLAYMATE for the bass and sub-bass with:

Various Artists - Bar 25 - Greatest Hits

Dirty Doering - I Would (Edit)
Marcus Meinhardt - Endjoy
Benno Blome, Rachele - Go Loose (M.In & Chriss Vogt Remix)
Animal Trainer - Wunderland
Philip Bader, Nico Stojan - Rootsa
Niconé, Sascha Braemer - Thänk You (Radio Edit)

For identifying the best soundstage from the three devices above I choose songs with more voices, women and male, to cover the midrange better, but also with instruments. When using Everest opamps (SS V6 Classic and vivid) instead of the default NE5532 I got an increase in soundstage and voices accuracy, it's like you got a step in front, more close to the stage. I find Everest opamp combination as being very good for classic music, jazz, rythm & blues. Chesky drums tests was sounding on Everest like placing the listener inside the recording room, with extreme accuracy and soundstage, all the details abounding into the ears. I assume the micro-details I hear are coming from the Vivid solid-state opamps that are acting as Low-Pass filter and headphones Voltage amplification inside the PLAYMATE. In micro-details and soundstage I an inclined to give my vote to PLAYMATE Everest, while PLAYMATE Basic is sounding about the same with PLAY and CV2+ on all songs tested.

While Conductor Virtuoso has a lower THD figure, this was not actually felt by my ears during A/B tests, so most likely headphones THD was more important here than DAC/headamp's THD. Between the three combos, the best price/performance and price/features ratios are making PLAYMATE Basic a winner for IEM's or very sensitive headphones (high SPL dB/mW), and for high impedance headphones and planars PLAYMATE Everest is the winner, given the match lower price vs. the CV2+.

Worth mentioning that PLAYMATE Basic combination has a lower background noise vs. Everest and if using very sensitive IEMs (16-20 Ohms, >100 dB/mW or >115dB/V) perhaps Basic might fit you better. Also, Everest is having a lower background noise then Conductor Virtuoso 2+, while PLAYMATE Basic has a lower background noise than PLAY. Hope that helps for those looking for a DAC/headamp combo for sensitive headphones.

Bottom of line, soundstage is very good with a great separation of instruments and voices. Overall sound is non fatiguing, a tad on the warm side perhaps (per my liking) but completely neutral.

Several digital filters are built-into the PLAYMATE DAC section (inside the ES9038 chip), to better accommodate our ears to the most pleasant sound we might like. How PLAYMATE measures, based on the different filters settings, could be read here: https://www.head-fi.org/threads/new...hangeable-opamps.894619/page-15#post-14782397.

Headphones used for the listening test:
- AKG K550
- AKG K701
- Beats Solo2
- Beyerdynamic DT880 (600 Ohms)
- FOSTEX T50RP-mk3
- FOSTEX T60RP
- Grado SR60i
- Hifiman HE-560
- SUPERLUX HD381F

Opamps used for the above tests:
- NE5532P
- JRC2114D
- LME49720
- MUSES 01/02/8920/8820
- SS V5
- SS V6 Classic & Vivid

MEASUREMENTS:

Maximum temperature readings measured with IR thermometer (22-23C room temp.) after several hours of intensive listening:
Top case: between 36-38 C
Bottom case: 39-40 C
Power supply: 33 C
IV: 72C
LPF/Gain: 69 C
XMOS chip: 57 C
PCB components: < 50C
Power regulators: < 50C
Output transistors: < 50C

Linearity starts bending visible at 0.00002mV (around -94dBV), then at around 0.000012mV (around -98.5dBV) it starts bending enough to consider the above voltage as being the lowest one accurately represented by this audio equipment.


Second and third harmonics are located somewhere around -100dB away from the fundamental, which makes them impossible to get listened by audience. Background noise is very low and makes it really hard to identify it with my sensitive 103dB/mW (121dB/V) 16 Ohms IEMs.



PRO:

Powerful, detailed, clear, neutral and also warmish sound.

Matches all the headphones with ease, no matter their impedance on sensitivity. Even it’s such a powerful headphone amplifier, I can comfortable listen to very sensitive IEMs (16 Ohms, 103dB) with a volume level between 15-25%, because of the way the built-in digital volume operates, more like a logarithmic volume potentiometer, but without the channel imbalance on low-volume and without the scratchy noises that might occur during the time on the analogue potentiometers. Switching to HE-560 planar cans will make me increase the volume rotary knob somewhere between 50-70%, depending on the music and my mood.


CON:

The beautiful and shiny aluminium case could get scratched, so some additional care is needed, especially if placing heavy headphones with metallic parts on top.

The EVEREST opamps combination (Classics in I/V and Vivids in LPF/Amplifier-gain) might "sound" too expensive for some, but with these opamps I got the best soundscene possible, musicality and microdetails. However, LME49720 in I/V combined with NE5532 in LPF/Headamp-gain worked like a charm for me too, punchy powerful bass and lot of microdetails. Nevertheless, with 4 x NE5532 from the BASIC version, sound is perfectly neutral and without background noise.

Note: The 8KHz spikes are generated by my measurement ADC (ASUS U7); sometimes it's simply there and I can't get rid of it, so the THD+N is also a bit higher due to this fact.

Hello fellow Head-Fi-ers,

This review will only cover the Virtuoso 2 headphones amplifier and not the Virtuoso 2+ DAC/headamp combo. If I'll be able to get the transport and DAC cards and test them, then I'll update this review later.

I purchased an "used-like new" V2 recently, about 5 months old, from a local seller. It was intact, barely used by the seller and only with his Fazor planars. I gave it a listen, of course...I liked the sound, so I paid the guy and picked up the V2.


PACKAGING:

Device was carefully packed into a double-case package, both cases having additional protective foam. It looks quite indestructible to me, nor my Yamaha & Pioneer speakers amplifier, nor my SVS active subwoofer and nor my 20-kilo-each CANTON floor-standing speakers were not packaged into two separately foam-isolated cases, so a big thumb-up for BURSON on how is dealing with packaging for a headphone amplifier!
The small and shiny aluminium remote control was packed in a separate case, along with the power cord and well made RCA-RCA stereo cable.

Virtuoso 2 has four rubber feet on the bottom that minimize vibrations and makes the sturdy case non-slippery, even if kept on a glass table.


LOOK & FEEL:


Impressive appearance with shiny and massive body and weight.

It weights about 7 KG, more than my 2 x 60W Pioneer speakers amplifier, quite stunning! The volume in the middle combined with so many kilos of aluminium gives me the impression of a powerful speakers power amplifier instead of a headphones amp.




On the front plate two buttons is all I needed: the small round input button for input source select and the volume rotary knob that can be used as MUTE if presses gently, so no additional buttons for the inputs or for the gain (there's no adjustable gain anyway), I really like this simplistic attitude.

Volume in the middle of the front plate gives to V2 the aspect of a power amplifier made out for speakers and not for headphones. Besides the volume control, this also controls the mute-output if pressed during the playback. The power ON/OFF switch is positioned on the backside, along with the 120/230V selector.




There is a 6.3 mm stereo jack plug on front-left, so a dedicated 3.5 mm to 6.3 mm jack adapter plug will be needed to be able to drive all single-ended cans.

The original small display is showing the output volume level; given the high power output of this amplifier this level indicator is a must have indeed. I've seen that with my planars the max. output level needed was around 40-50%, depending on the music used as playback. Instead, for sensitive cans, dynamic or IEM, output level was somewhere between 15-30%.




Remote control is made out of the same shiny polished aluminum and it has 5 buttons for volume, input source selection and mute.

Inside there's a Lithium battery that might be replaced after 5-6 years of service, perhaps faster if used daily.




Entire body is made out of polished aluminium, with case thickness of no less than 6 mm!

Six mm means a lot, I've seen speakers power amplifiers using such thickness for the output stage transistors, so really massive and lot of weight added. More weight means less vibrations, so this is a good thing, not mentioning the very fast heat dissipation from inside to outside.

Robust and built as a tank is all I can say, but being aluminium some care might be needed, otherwise scratches could appear, especially if metallic parts are placed on top, like headphones, house or car keys etc.



The "beast" has a power supply similar with speakers amplifiers, with big shielded transformers and 8200uF ELNA capacitors.




Back plate with the input source gold-plated RCA plugs and pre-amplifier DAC/PRE outputs. The 5-years warranty needs manual registration to manufacturer's website.

Input sources are selectable via the front button; there are two analogue inputs that can be chosen from, but for the Conductor V2+ it can also be selected the Coax/Tos/USB inputs as well. There are also DAC-Out and PRE-Out outputs on the back along with the inputs. Outputs are very useful for the V2+ when paing it with external amplifiers or with audio monitors.

After several hours of continuous listening to Conductor V2 paired with Hifiman HE-560, with moderate-to-high volume, V2 is barely warm on top (top case is 29.8 C inside a 22.4 C room), so now I understand how so many kilos of "aluminium heatsink" can lower amplifier's temperature.


INTERNAL PARTS, BUILD QUALITY

POWER SUPPLY:

Conductor V2 has linear-type power supplies created by two fully shielded 70 Watts high density toroidal transformers and linear regulators, one dedicated for the digital part and another one dedicated for the analog part.


Both transformers being fully shielded means that no electro-magnetical interferences (EMI field) will diffuse onto the electronics board and no mains hum will get to the headphones.

The transformer dedicated to the amplifier parts is delivering 2 x 24V AC, so quite a beefy output voltage for a headphones amplifier (not the perfect comparison, but my 2 x 60 Watts Pioneer speakers amplifier has a 2x32V AC transformer inside).

Separating digital and analogue power supplies will lower the background noise, increase the dynamics and minimize interferences from the digital parts, like volume control or relays coils.



Each transformer rail has dedicated powerful rectifiers, so a total of twenty diodes! Yes, 20 diodes, because Conductor V2 is regulating full-wave of the AC voltage, not only half-wave.



For the analogue parts, the amplifier itself, voltage is regulated by the two powerful MOSFET transistors IRF610, after ripple is much reduces by the 4 x 8200uF ELNA polaryzed capacitors.



There are also two yellow LED lights on the internal board that show if the power in ON and if no defects occur.


TRANSPORT AND DAC SECTION:

The transport is done via an well-known XMOS chip that takes care of the USB path. I've tested this transport on Windows 10, OS Sierra, OS High Sierra ans OS Mojave and everything worked like a charm. Several FLAC and DSD files were played without encountering any sound skips, not even while playing remotely via Wi-Fi network from my home Win10 NAS.

DAC card is using the "legendary" ESS 9018 PRO chip and a custom 1ppm TCXO and no opamps are used, everything is built with discrete high quality components. Also, there are no capacitors in signal path! Several power regulators are used to achieve a very low noise and also to minimize any possible ripple coming from nearby mains transformers.

AMPLIFIER SECTION:

BURSON Audio is well-known for their Class-A audio equipments and Conductor V2 is as well a pure Class-A and also a fully discrete headphones amplifier.


Silmic II capacitors are reducing the ripple across the powerful output stage complementary transistors



Volume control is fully digital and is controlled by the stereo audio volume chip PGA2130 made by Texas Instruments.

This chip is having a dynamic range of 120 dB (from -95.5 dB to +31.5 dB) and noise free level transitions, so no additional noise will get added. Having such a big dynamic and a smooth +/-0.5 dB level between two adjacent transitions means that no additional gain controls are needed, like most headphones amplifiers do usually have. That means less control buttons to adjust and combined with the visual volume level LED display our ears will get more protection against high volume levels. I don't even remember for how many times I forgot the gain switch from the backside to HIGH-position and swapped the planars for IEMs on my Matrix HPA-3B headamp, so...really ears blowing!



The RCA plugs are very well soldered ontot the dedicated smaller PCB. There are two analogue inputs and for the Virtuoso 2+ there are additional three digital inputs too: USB, TOSLINK and COAXIAL. DAC-Out, PRE-Out along with the analogue and digital inputs and the volume control chip are actually creating an internal pre-amplifier able to control audio inputs and output level,



Bad news for op-amp rollers: best op-amp is no op-amp! Conductor V2/V2+ has no op-amps to swap inside and gain stage amplification, as well as Class-A biasing are both fully discrete, done with complementary bi-polar transistors 2SA970/2SC2240.



Output stage is created around the powerful 2SA1930/2SC5171 complementary bi-polar transistors, two pairs for each channel, thermally connected to the bottom aluminium case.

These powerful transistors are having an absolute maximum operating power of 20 Watts each for heatsink temperature lower than 25C! Not saying that these transistors will drive my floor-stand speakers, but are definitely driving all of the dynamic and planar headphones I have, with it's max. 11.5 V RMS / 8.2 W per channel. Actually, I was driving my Pioneer 8-Ohms speakers for few minutes at about 9W/channel, without overheating, but seriously: don't you ever do that!

All the output transistors are connected to the bottom aluminium base via normal screws and thermal paste, so heat dissipation from the output stage is done on the bottom.

Audiophile quality Vishay metallized resistors and SILMIC II ELNA capacitors can be seen across the board, to further minimize the output noise on signal path, but also to further lower power AC ripple.



Headphones, but also the output stage transistors are protected by an output relay that gets activated only when headphones are connected. I can actually hear the relay working when I insert the cans into the 6.3 mm jack. Of course, if something gets defective inside, the relay will not let any DC-volage passing onto the headphones.


RMAA & ARTA tests (DAC section only):



The DAC section measures very well, with very well controlled harmonics at -100dB, no mains hum and perfect linearity. The XMOS transport works flawless without the need of drivers in Win10 and Mac OS, but installing the original BURSON drivers will help in taking advantage of ASIO.

DAC is completely neutral and transparent, and could be paired with any external amplifiers, per your wish. Connecting the RCA DAC-Out to an external amplifier can be done via a regular cable with RCA plugs on its ends (any headphones and speakers amp will work just fine). The volume control of the DAC is adjusted via the internal ES9018S DAC chip and not from the PGA2310 chip (this is only used for the preamp section).

RMAA & ARTA tests (amplifier only):




For 5V RMS per channel I got very good numbers:

Frequency response (20-200000 Hz): +0.21, -0.09 dB
THD: 0.008%
Noise (A-weighted): -102.5 dB
Dynamic range: 102.6 dB
IMD + noise (A-weighted): 0.006%
Crosstalk (left/right): -67.8/-68.3 dB



HOW DOES IT SOUNDS?


Soundstage is very good with a great separation of instruments and voices. Women voices are not strident, but are very present and clear. Men voices are having a "larger" presentation, probably given V2's larger soundstage and this is helping a lot when listening to Classical music.

Nice and probably a little bit warmish sounding amplifier, so totally non fatiguing, not even after more than 4 hours of continuous listening. This is a headamp that combined with comfortable headphones will make you forget you're listening to headphones, instead you're only enjoying the sound. However, spending several hours, especially with loud music might affect our hearing on long term, so listen with care and do take some breaks after 1-2h of listening.

Not running hot Class-A amplifier which sounds so great will probably make it of a kind, hence totally recommended as an audiophile powerful headphone amplifier.

Subjective tests above were done with a Burson PLAY DAC connected to V2's analogue input source.
Headphones used were: Superlux HD381F, Beats Solo 2, Grado SR60i, AKG K550, AKG K701, Beyerdynamic DT880 600-Ohms, Fostex T-50RP mk3, Hifiman HE-560.
All these cans were sounding perfectly with Conductor V2, just the volume rotary controller was adjusted per can's sensitivity.
I've listened to Classics, Jazz (instrumental and vocal as well), Rock, Pop, Disco & Dance. I couldn't find a glitch, everything was sounding perfectly.


SCOPE tests:

Virtuoso 2 "passed" sine-waves and square-waves test as expected. Red is generator's input, blue is V2's output for about 2V RMS.

From my perspective, this amplifier measures virtually perfect, without any noticeable phase-shifts, time-delays nor attenuation of low or high frequencies!

PRO:
- Huge output power, I was able to drive 8-Ohms speakers up to 9W/channel (please don't try this at home!).
- Perfectly flat between 10 Hz and 30 KHz.
- Virtually perfect output representation of common sine-waves and square-waves (20 Hz, 1 KHz, 20 KHz).
- Very low THD + noise with great dynamic of > 102dB (a CompactDisc has 96dB of dynamic).
- For a pure Class-A operation I was expecting it to be way much hotter (it's about 30C on top).
- DC-coupled with dedicated protection.
- No opamps & no caps in signal path.
- Separate shielded AC/AC transformers, for digital and analogue parts.
- Huge 8200uF/35V ELNA caps to lower AC ripple & noise.
- Five power rails, each one being regulated by a full-wave 4-diodes bridge rectifier (a total of 20 fast powerful diodes).


NEUTRAL:
- 3 Ohms output impedance might seem a bit higher for some purists, although it doesn't affects any of my cans, not even my 16-Ohms IEM's.
- Given its high power output might not be recommended for sensitive IEMs.


CON:
- No EMI/RFI filter inside (never happened to me, but some people might hear electrical buzz/noise); however, an external EMI/RFI and/or isolation transformer could get added later.

Bottom of line, this is a very well built & high quality headphone amplifier that might represent an "end-game" for many audiophiles and musicians.

I received about one month ago a 2x40W speakers power amplifier having a 5.25” internal computer bay size (CD/DVD-ROM unit like). I was really surprised when I saw its size because I’ve never seen so much power from a stereo power-amp working in A/B class inside a such a small CD/DVD-like case, so please understand my wonder. I would understand a Class-D amplifier inside small “package”, but not Class-A/B, so let’s see what is this about.


(courtesy of Burson Audio - Melbourne)

Per design simplicity, BANG has no volume knob, so we need to use an audio source with built-in volume control or a preamplifier between your audio source and BANG! This is why I’m calling it a power amplifier or simply “power-amp”, because there’s no way to adjust the volume unless you use a volume-controlled input source, like PLAY for example or any other source volume adjustable. Also, passive or active preamplifiers will do as well if connected between the input source (DAC, CD etc.) and the BANG. Being a power-amp, without volume control, is somehow unusual for me because I was used to see only professional equipment built this way (power amps are usually big monster delivering KW of power during concerts or wedding), but I think this a good approach done by BURSON, given the small size of the amplifier and the willing to pair it with devices like PLAY that already has volume control.

Specifications:

Input impedance: 100 KOhms
Frequency response: ± 1 dB 0 – 20Khz
THD: <0.03%
Output impedance: 1.5 Ohm @ 1 kHz
Signal-to-Noise Ratio: 92.5dB

Inputs: 2 X RCA (2V RMS line level)
Outputs: 2 X Speaker Outputs

Power/Impedance, Signal To Noise Ratio, Separation between the two channels:
- 40W/4Ohm, 91db, 99%
- 29W/8Ohm, 91db, 99%
- 15.2W/16Ohm, 91db, 99%

Power Supply 100-240V AC (12V 10A)
Weight: app. 2.5Kg
Dimensions: 210mm x 145mm x 45mm

You can see from the above specs that this power-amp will perfectly fit inside a regular desktop computer, making it perfect for someone who wants to play games, watch movies and listen to music on passive stereo speakers at a more than decent audio quality. No subwoofer output available on BANG, it’s just a power stereo amplifier, so if you need to a dedicated bass speaker unit then you might need an active subwoofer to accomplish that, ideally able to get the input signal directly form the speakers plug (not all subs are able to be driven directly by a 40 W amplifier, so please read sub’s datasheet first!). This should probably make it the first Class A/B power amplifier that perfectly fits inside a regular desktop computer and also being able to get power from a dedicated power supply or from the internal computer’s PSU via the MOLEX plug.

I am considering this design and its small size a great advantage for gamers, audiophiles, but also for regular computer users that don't want to spend lot of money on power amplifiers that occupy lot of desk/room space. Enough power in such a small-size case was a huge challenge for BURSON, because most of power amplifiers that might fit inside a desktop computer are usually Class-D and not Class-A/B, so quite a challenge indeed (just saying, not willing to start a debate between amplifiers classes here).

Like a good perfume, BANG is small, packed inside a beautiful and thick black anodized aluminum case that acts as a big heatsink across its entire surface, very well built and able to deliver enough power to drive our speakers inside the bedrooms and living rooms with a crisp and detailed audio quality. All we need is a volume-controlled audio source like PLAY or just a regular DAC with volume knob control and a good RCA-RCA interconnect cable or the Cable+ Pro.

BANG comes with an external power supply able to deliver 12V/12A (120W) which is more than enough for the "big" BANG. It's a low-noise SMPS (switched-mode power supply) that can be easily replaced by the power source from inside your computer by directly connecting it to the existing "molex" connector.

Power amplification is done by two reputable integrated circuits LM3886TF that do the job very well. There's plenty of musicality, crisp and detailed sound and the 4 power regulators inside are able to deliver about 5 AMPS per each of the 4 rails, so bass speed and attack will never be a problem for this amplifier.

The 2 x LM3886TF power chips (the 2 gain switches and the input op-amp on the right)


Above picture with all inside components (the 2 gain switches and the input op-amp on top-right, the power regulators on the left)


With all op-amps tested the DC-offset voltage was very low for such a powerful amplifier, few mV only, so I consider this very-low DC-output a highlight for BANG. I've seen LM3886 kits tested on several audio forums that are pushing more than 100mV per each channel, so BANG's design seems to be a very good one.

I was also measuring the power rails of this power amplifier and I got 2 x (+/-24.5V), as BANG has 4 rails because of its 4 SMPS power regulators. This way BANG can deliver a very fast bass with lower THD, as each power regulator can sustain a 5A load with ease (4 rails means a total of 20A of max. instantaneous current, 10A per each channel!).

Power regulators (lot of ripple reduction ELNA capacitors and noise reduction coils)


I was able to measure a maximum temperature of about 50C on the two LM3886TF chips after pushing some loud music on the speakers, inside my room air temperature was 25-26C (device was powered ON since >4 hours and case left closed but without the screws, so it only took me only few seconds to open the case and use my IR thermometers) and about 45C on the op-amp and surrounding components. PSU's capacitors were a bit warmer, around 50C, like the LM3886 chips, same temps on the 4 power regulators. however, pushing BANG to the limit may heat things much higher, but with a good ventilation around I see no problems, after all it’s a speakers amplifier not a headphones one.

The internal design is pretty straight forward, there is a dual op-amp used in the gain-stage (input buffer), to amplify the input source volume so the output stage made of 2 x LM3886 chips to be able to deliver enough voltage for the speakers even if they’re fed by low-voltage input source, as cellphones. This makes this power amplifier versatile, compatible with lot of input sources and also a very good equipment to swap op-amps, which is always a very good thing for us, head-fiers.

Choosing between the default NE5532 and BURSON op-amps will change the sound flavor a bit, depends on everyone's ears and speakers. Also, the DC-output voltage on speakers-out will change. I was able to measure around 1-2mV of DC when using MUSES8920 and between 15-20mV of DC-voltage when using NE5532 or SS V6, so very low numbers, but when trying different op-amps you might get different numbers. Optionally, you could use a Digital Multi-Meter after swapping different op-amps, just to be 110% sure you’re not using a defective or a non-compatible op-amp).

We can swap here every dual op-amp we want if it's designed for audio use, but for non-audio op-amps (e.g.: faster op-amps, dedicated for video applications etc.) we need to check op-amp’s datasheet or consult BURSON technical support for op-amp compatibility with BANG. A defective op-amp or avery fast and oscillating op-amp might have a higher than acceptable DC-offset voltage on outputs (>100mV) and this might affect the output sound on some sensitive speakers (usually very sensitive speakers having a lower-impedance: 4 ohms, >92dB/Wm sensitivity).

The input op-amp is working with a selectable gain of about 0.75/1.5X and is powered by dedicated low-noise LM7812/7912 linear regulators, so op-amp's rails voltage is +/-12V. That means most audio op-amps should work here, but again: double check op-amp datasheet or consult BURSON for any questions about op-amps compatibility.


Close-up with linear power regulators for the input op-amp


The powerful LM3886TF are working at a gain of 20X, but between the gain op-amp and the output stage chips there are two gain switches, one for each channel, that help us choosing the proper gain for our speakers, based on the input signal voltage. Basically, these gain switches are lowering input gain’s output power in half, chaning the gain form 1.5X to 0.75X.

The final output stage made out of 2 x LM3886TF is powered directly from the 4 boost-regulators: 2 x XLSEMI 6019E1 and 2 x XLSEMI 4015E1 that are creating a dual-mono power supply able to sustain the output load with ease. The 120VA SMPS power supply has enough power reserve to boost the bass instantly into our speakers.


Close-up with power regulators for the LM3886 chips


Few recommendations for those that might want to put this big-baby inside their PC case:

• We need to be 110% sure that PC's internal PSU is able to sustain an additional load of 120W taken only from ONE of the 12V rails! Yes, 12V/10A nominal power, so 120W of spare power when your computer could be gaming or benchmarking under full-load (bass power spikes could take more than 120W!).
• We should take into consideration the amount of digital and analog "audio noise" our computer’s PSU might inject into the audio amplifier, as usually PC PSU's are not very low-noise by design (feel free to check the AC ripple & noise for your PSU, if tested already, here: http://www.jonnyguru.com/modules.php?name=NDReviews&op=Review_Cat&recatnum=13). If we do have a low-noise powerful PSU then we might be better if sticking to the original 12V/10A power adapter provided by BURSON which is really low-noise and designed for audio use.
• The amount of heat generated by the BANG power amplifier could be higher than the amount of heat generated by a regular computer CPU, as BANG could dissipate more than 100W of pure heat when working in full load, so not having a very good cooling inside the PC case might not be a good thing to try BANG inside the PC case. I'm speaking about really good cooling, maybe with positive air pressure and no other 5.25" devices like DVD-ROM units on top and bottom of BANG to suppress the airflow.

I was listening few days ago through BANG to some 2017/2018 Pop/Dance music using as input source Lenovo X230, Lenovo T440, MacBook Pro 2015, iMac 27, but also Burson PLAY and ASUS Xonar U7 that both have volume control knob. Despite ASUS Xonar U7 being able to deliver only max. 1V RMS on RCA outputs, I'm really impressed by BANG’s output power, clarity and channel separation (sound-stage). I realized that for normal listening levels for my living room (25m2, approx. 2x20W of music power) BANG's case it's actually not heating up so much, it is warm, but not more than 50C on top and when listening to a music with a greater dynamic, like Jazz or Classics, temps are even lower.

BANG sounds powerful, with a deep punchy bass, has a good sound-stage and it's completely neutral. See the below RMAA as well:


BANG has a perfectly flat response up to 20 KHz


When feeding the BANG from ASUS U7 DAC the volume was powerful enough, but not that high like when using PLAY or some laptop's jack-output, so depending on the input source used, BANG’s internal gain might need to be set to highest or lowest position (I - high, ON - low). BANG amplifier if powerful enough, even when feeding it with low-voltage input sources like 1V RMS or even lower, like my old Nokia phone, so definitely lot of gain inside BANG.

Speakers used for this test were my good old Pioneer S-H520V-QL, 1m height floor-standing speakers, 87dB/W @1m, 2 x 14 cm woofers and 1 x 2.5 cm tweeter, 8Ohms, 130W RMS. Modest speakers, but really big sound and great soundstage when paired with BANG.

I tested play on several laptops and desktops, but only with BANG connected externally. For BANG installed inside the computer I got a very well ventilated desktop tower to do some tests:

• 10-core i7 6950X CPU water-cooled (140 Watts)
• 4 x GTX 1080Ti in SLI-mode (4 x 270 = 1.080 Watts)
• 128 GB RAM
• SSD + HDD
• BURSON PLAY (60 Watts)
• BURSON BANG (120 Watts)
• PSU Platimax 1.700 Watts
• lot of 120 fans to provide a very good cooling, based on positive airflow

1st test done with BURSON equipment standing on my desk:
- room temp: 26 C
- after 1h PLAY was >40C and BANG was 45C (peaceful and not loud music, no much power drawn)

2nd test done with BURSON equipment inside a well ventilated tower PC:
- room temp: 23 C
- after 1h PLAY was >27C, because it was on top of the case, and BANG from the middle of the case was about 25C (peaceful and not loud music, no much power drawn)

Seems that in my case BANG is cooler if used inside a very well-ventilated computer case with vents in front of the case and fans on top and front, where the 5.25" bays are located.

Note: BURSON does not recommend BANG to get installed inside a computer case, because under most circumstances it might get overheated!


Some tests and measurements

I was able to “build” a 4.9 Ohms/40 W dummy resistor to test the BANG with my scope and I got about 14.5V RMS @ 4.9 Ohms for 1 KHz sine-wave just before starting to distort very little bit (see the bottom of the sine-wave. That's almost 43 Watts of RMS power for each channel, so when listening to music/program the output power could be a bit higher (music power vs. RMS power).


13.55 V RMS @4.9 Ohms 37.5 W RMS (no visible distortions)


14.5 V RMS @4.9 Ohms 42.9 W RMS (the bottom starts showing few distortions)


I couldn't find or DIY/make a precise 4 Ohms dummy resistor to test the output power, but given the above result for 4.9 Ohms dummy-resistor I would approximate BANG’s max. power @ 4 Ohms speakers being a bit over 45 W RMS per channel. It’s more than manufacturer’s specs, but let’s not push the amplifier beyond its max. limits to prevent overloading and overheating. I’m only doing these tests to see if my BANG is within manufacturer’s parameters and trust me...it is beyond the specs.




Lowering the input source & output volume to 14.3 V RMS or below will make the above sine-wave to look perfect, without any visible distortion on my scope, that would be about 41.7W/channel with zero visible distortions on my scope.

After reading several articles over the Internet about Gainclone amplifiers, like LM3886 chip amps, I realized that the most unpleasant situation is when the LM3886 chips start to oscillate, consume lot of power from the power supply and then heat up a lot. This seems to be happening when circuit’s schematic or the PCB board are not designed properly and usually when high capacitve loads are on speakers outputs, like for example cheap 25 m long speakers cables. Perhaps some LM3886 amplifiers from other manufacturers might oscillate a bit when driving very high capacitive loads, but BANG is just a damned stable amplifier! I couldn’t make oscillate at all, not even after adding 0.33uF capacitors on its outputs (strongly not recommended, seriously do never do that!). As a regular speakers cable has somwhere between 10 and 200 pF / meter, then the 0.33uF capacitors I have added to my above test is somehow similar with testing BANG power-amp on a few kilometers long speakers cable. More about speakers cable capacitance cold be read here: https://en.wikipedia.org/wiki/Speaker_wire or here: http://www.roger-russell.com/wire/wire.htm.


BANG driving 0.33uF capacitive load (>20V RMS of 1KHz square-wave; red line is the input source, blue is BANG's output). No ringing, no phase shift, no oscillations!



Output coils/inductors and powerful resistors installed to prevent unwanted oscillations



The green resistors & the WIMA red capacitors make a R-C filter, parallel with the outputs (part of the Zobel network) to combat any possible oscillations)


I was trying to calculate BANG’s output impedance and dumping factor of the amplifier as well, so I took as reference a 7 V RMS output voltage with 1 KHz sine-wave from an external generator, when no load connected on speakers outputs. After adding my test dummy resistor of 4.9 Ohms I can see a drop of 2 mV RMS (6.998 V RMS, that would be 10 W RMS power). As the voltage difference is so close to zero I can't measure properly the output impedance, this is caused by a “very close to zero” Ohms output impedance, that meaning a very good dumping factor.

During the above tests internal chip temperatures were not alarmingly hot and no thermal protection occurred during this test, that means that BANG’s outer case can dissipate the heat properly if ventilation is not obstructed.

I got thrilled last year when I saw BURSON announcements about lunching the PLAY DAC/headphone amplifier combo device. It was one of the best combo I've seen on market at that price, yes...the basic PLAY with NE5532/5534 sounded awesome and for that price was a steal. Now they brought on the market the FUN and BANG amplifiers, just like that...probably because they can do it.

I was immediately asking myself "How will FUN sound? What's really inside FUN? Does it worth the money indeed?" And the miracle happened recently when I received a powerful Class-A transistors headphone amplifier, “FUN” from BURSON Audio, to give it a test. It took me few weeks to “warm it up” with lot of music listening, then I started to overload it with sine-waves, 2 Watts RMS power @ 30 Ohms loads for several minutes and it’s response was perfect on my scope with no overheating, no volume change...just the same clean output. Temperature seems to be a bit lower than BURSON’s combo PLAY, somewhere about 40C on top after several hours of active listening, so quite cool for a pure Class-A headphone amplifier.



I was closely inspecting the PCB and couldn’t find any capacitors in audio signal path, hence when using BURSON’s solid-state V6 op-amps there are practically no caps and no op-amps in the signal path, just transistors and resistors. This design with no caps in signal path and solid-state “opamps” like V5 and V6 translates into a bigger stage with lot of fun and musicality, because SS V5 and V6 op-amps are designed for music and audio listening.



I’ve tested the unit with both V6 Classic & Vivid SS (singles) and also with NE5534 op-amps the output DC-offset voltage is very low, so FUN could be used with 16-ohms headphones without issues. Depending on the op-amp used, measurements done after a bit of warm-up (>10 minutes) gave me between 1.5mV and 3.5mV, so a low DC-voltage. Also, I've noticed the background noise is almost non-existent with my very sensitive 16-ohms IEMs, even when volume knob passes the 12-o’clock (no input source connected!) so quite a versatile headphone amplifier able to drive headphones from 16 Ohms to 600 Ohms.

Seems that solid-state op-amps from BURSON need a few minutes to warm-up till their parameters are meet, so I recommend a 5 to 10 minutes warm-up prior to listening to your favorite songs. This is also a good thing for the capacitors inside FUN to warm-up a little bit, so it could be a good thing to do a bit of warm-up with most solid-state op-amps prior to listening to the music (well...tube amps need 20 to 30 minutes of warm-up).

FUN is powered by a 12 V/70 W brick adapter, but it can also be powered by computer’s PSU via the dedicated MOLEX plug. Internally, the 12 V gets up-converted to 2 x dual +/-17V rails via dedicated 5 Amps boost regulators. The internal symmetric-dual PSU from FUN is created by 4 x SMPS power regulators (XL6019E1 and XL4015E1), named by BURSON Max Current Power Supply (MCPS) and operating to a speed of above 170 KHz, able to deliver lot of power into the output stage instantly, so PRAT, attack and bass speed are perfect on FUN, especially if combined with Burson’s solid-state SS V5/V6.



I find the above power regulators/boost converters a very good approach for a device that should be used outside or inside the computer's case, depending on everyone's mood of the day and their desk setup. Basically, connecting FUN inside the computer and powering ON via the MOLEX plug will make the computer very sound appealing and a very good addition to gamers and also for those willing to listen to music under decent conditions without spending thousands of bucks on this. There're also Mic-In/Out and Line-In/Out plugs on the backside and myself as a computer user and PLAY & BANG owner I do much like that.

Inside components have been very well chosen from reputable companies and with a very good quality like: polarized polymer and aluminium caps from ELNA, none polarized caps from WIMA, Vishay SMD low-noise MELF resistors, Toshiba 2SA970/2SC2240 transistors (TO-92 case), Toshiba 2SA1930/2SC5171 output-stage transistors (TO-220 case), ALPS logarithmic potentiometer, Panasonic Japanese fast relays. Yes, 4 big transistors per each channel, the same output stage used inside BURSON CONDUCTOR few years ago. Also, FUN's PCB has a big ground plane across sensitive components and lot of polymer caps to combat ripple and noise and this makes FUN quiet and compatible with sensitive headphones like IEM's.



FUN under stress-tests here:

The RMAA tests show a perfectly flat frequency response across entire audible spectrum with a good dynamic and low noise.


Frequency response (perfectly flat till 20 KHz)


Dynamic


Signal/Noise Ratio (50 Hz hum nose is lower then -102 dB)


For 600 Ohms output resistance I got over 10V RMS output voltage for 1KHz sine-wave with 2.2V RMS input signal. That's about 170 mW of power @600 Ohms cans, almost twice my Beyerdynamic DT880 600-Ohms cans can handle.


10.15V RMS @ 600 Ohms


For about 30 Ohms output resistance I was able to get absolutely perfect sine-wave with no visible distortion with my scope until voltage raises to about 7.7V RMS. In the below image you can see there are no distortions on 1 KHz sine-wave for the 29.5 Ohms dummy resistor I used, which means about 2 W/channel @ 30 Ohms.


7.6-7.7V RMS @ 30 Ohms


Below you can see how the down-low bass "sounds" on my scope. Practically, both sines from the signal generator and the FUN are perfectly superimposing without any bass roll-off, even if we're speaking about inaudible 10 Hz bass here!


The perfect output of a 10 Hz sine-wave! (red sine is the signal generator, blue sine is FUN's random channel)


DC-output with 2 x NE5534 in voltage-gain was 1.6mV/1.7mV for both channels. With 2 x SS V6 Classic (singles) the DC-output voltage is few mV more, so still negligible. However, depending on the op-amps used and also after several hours of warm-up the DC-output might increase or decrease with few mV. Output DC-voltage is very low and it’s backed-up by a dedicated protection circuit (UPC1237HA) on the output jack to protect the headphones if wrong op-amps are installed/swapped or in case of defects that could possible inject DC-voltage on outputs.

I measured FUN's internal output impedance with sine-waves of 1 KHz @ 1V RMS per Sengpielaudio-calculator (600 Ohms) and I got 0.39 Ohms per each channel. I needed a less than 4 Ohms dummy resistor to lower FUN's output voltage to 90%, so this amplifier has a very good dumping factor for a headphone amplifier.

This powerful 2W /channel @30 Ohms headamp is promising a lot for its price, even if choosing the default/basic version with NE5534 op-amps. Also, opamps like AD797, OPA134 or similar single op-amps will do the job very well, for people not willing to purchase, for the moment, the SS opamps from BURSON.

I was able to calculate FUN’s THD for 600 Ohms load by using this online calculator: http://www.sengpielaudio.com/calculator-thd.htm, hence the THD of 0.016% I got from the RMAA tests I’ve ran, translates into about -96 dB of distortion, a very good figure indeed and on pair with the SNR measured. So for 600 Ohms the results are very good, better than the ones published by manufacturer. Usually BURSON is publishing their results based on the worst case scenario, kinda different than what most other manufacturers are doing (probably to impress potential customers).

Now enough with the measurements and technicalities, how does FUN actually sounds?

In the past month I got plenty of time to listen to FUN with several headphones, including:

• FOSTEX T50RP-mk3
• Hifiman HE-560
• AKG K701
• AKG K550
• Beyerdynamic DT880 (600 Ohms)
• Beats Solo2
• Grado SR60i
• SUPERLUX HD381F

I was mainly listening to FLAC 16/24 bits @ 44 to 384 KHz and DSD 5.6 to 11.2 MHz file formats from BURSON PLAY DAC used as source and I got perfect compatibility across all headphones from above. I very much liked the analogue volume control from FUN that makes the device totally compatible with sensitive IEMs, a very good thing for such a powerful amplifier lacking a gain switch.

Speaking about IEMs, even if FUN is so powerful, I found it a very good match for my 16 Ohms sensitive IEMs because I was able to change the volume from PLAY (digital volume) and from FUN (analogue volume) at the same time, giving me a better protection against sudden volume changes. With PLAY combo the volume was somewhere between 10-15%, but with BANG the knob volume was around 11 o’clock.

I was able to get a fluid and melodious sound with a big soundstage on the Jazz and Classical genres and, despite its neutrality, with SS V6 op-amps I got the perfect bass and trebles for Pop and Disco music on all headphones used. Seems that the powerful Class A amplifier combined with its low internal-resistance makes FUN a versatile amplifier for about all compatible headphones (well, Hifiman HE-6/SE cans may not be driven to their max. potential, but you should try BANG for that).

Manufacturer link to the product: https://www.bursonaudio.com/products/fun/.

BURSON PLAY

I received this wonderful DAC/headamp combo a couple of weeks ago from BURSON-Australia to give it a listen and write a detailed review here, many thanks to Charles for that. This is what I did actually, I gave it an over 200 hours of burn-in combined with intensive listening tests, mostly Jazz (oldies, but also contemporary), Blues, Rock, Classic music and Club hits as well, so I did covered most genres of music I usually listed to.


Photo: BURSON courtesy

For me, as a computer engineer, but also an electronics-hobbyist, it's very important what's "inside the box" and how the device measures, but also what kind of components manufacturer is using when building the final product.

Well, I was amazed that inside the PLAY Burson was using same high-quality components like in a high-end device: Dale resistors, ELNA Silmic II and ELNA Tonerex capacitors. Given the 5.25" form factor and Burson recommendation this DAC/headamp combo was designed with PC users and PC gamers in mind, so given the "target audience" I wasn't really expecting such audiophile-like components inside.


Inside components view


Powerful Class-A transistors amplifier


Gold-plated plugs and protection circuitry


Backside view of the PCB (see the ground-plane)

Now I'm going to dig into this baby a little bit.

The USB module is connected to the mainboard through a 7-pin adapter, so it's easy to take it apart and swap it for another module, in case of RMA for example. Also, this modular design makes possible a future upgrade, in case BURSON might think there's place for improvement. Who knows, maybe an USB 3.0 card or a SPDIF or RIAA converter or perhaps a newer XMOS chip or...just my imagination? The inside firmware can be future upgradable via the 3 volts 4Mb 25P40VP serial flash memory: M25P40 Serial Flash Embedded Memory - Micron Technology, Inc.. Entire USB module is getting the +5V power from a dedicated LT1085 low-noise regulator, so no power noise & ripple should get injected from the PC's power supply.


XMOS USB module

There's a low-power USB hub controller on the USB module, GL850G connected to onboard dedicated 12 MHz crystal. This has an 8-bit RISC processor inside that quickly responds to USB host requests. This USB hub should minimize PC's USB host ripple and noise and also to power the USB chip via the internal low-noise regulators.

The USB transporter is a XMOS XU-208 chip from the latest generation on the market, xCORE-200: XU208-256-TQ64. This is a 32-bit chip powered by 8 x real-time logical cores running at a frequency of 500 MHz. It gets the clock from the onboard 22 MHz and 24 MHz oscillators.

By the Digital-to-Analog conversion is taking good care the Reference DAC chip developed by ESS, ES9018K2M, getting the clock from the onboard 100 MHz oscillator. This is a high-performance 32-bit, 2-channel audio D/A converter able to natively decode both PCM and DSD formats with a dynamic noise up to 127dB and a THD+N of -120dB. It has also a digital volume control and an internal DSP with built-in "click-free" soft mute feature to suppress any possible popups when switching between PCM and DSD or vice-versa.


ESS DAC and the low-noise power regulators

The DAC chip is powered via the supplied +12V power source that is later lowered to +5V by a dedicated LT1085 low-dropout & low-noise regulator (different LDO than the one used to power the USB module), then gets lowered again to +3.3V by the ultra low-noise CMOS linear regulators ADP150 made by Analog Devices (9uV RMS across 10 Hz to 100 KHz).

Moving from the XMOS USB interface and ES9018K2M DAC further till headphones output plug, the PLAY version with SS V5/V6 opamps included is probably the only DAC/headamp combo designated for use inside a PC case that is using from head to tail only discrete components. Yes, transistors and high quality passive components, without any integrated chips in signal path, because the SS V5 and SS V6 operational amplifiers are 100% discrete and not regular IC chips! Also, I was unable to identify any capacitors in signal path either, by the DC output voltage is taking care an additional protection circuit that acts a relay on headphones 6.3 mm plus.

Microphone mono 3.5 mm jack is connected to the HS-100B chip which acts as Analog-to-Digital converter in this scenario. This is a 48K / 44.1KHz Sampling Rate Analog to Digital converter that convert signal getting from the microphone to digital PC format. It actually measures very well for a input source for microphone:


Microphone/IN frequency response


Microphone/IN signal response for 1 KHz signal

The output sound of the PLAY is having a pristine clarity, a very good soundstage, clear and upfront voices with extreme details in instrument reproduction. While listening to DSD Scott Hamilton - Ballads for Audiophiles I was able to detect on my headphones the correct positioning of every instrument on the scene, it's like being able to listen to all micro-details properly and to enjoy the music in a large soundstage. I was also amazed by how saxophone sounds while listening to more DSDs with Coleman Hawkins and Charles Lloyd; this is actually the best DSD DAC player I have at home at the moment and I really think the sound of the DSD format on the PLAY is awesome. I was specifically listening to jazz and sax because I'm very sensitive to this type of music and if doesn't sounds right then my ears are easily getting irritating (not the case with PLAY!).

PLAY measures very well too, perhaps a little bit better than the original specs; I've found no channel imbalance and a perfectly flat frequency response, combined with a neutral sound on both RCA and 6.3mm plugs:


Frequency response


Dynamic range & noise levels


1KHz frequency response


Jitter


Impulse response

The 2-Watts Class-A inside amplifier is able to easily drive both dynamic and planar headphones, from up to 600-ohms. As you can see from the below picture, I was able to push it to 7.4V RMS with 1KHz signal/30-ohms, meaning 1.825W/30-ohms of power on each channel. In case you're wondering how can it get about 2W/channel from a 12V PSU: no, it actually can't, so there are inside a couple of converters able to pump-up +/-15V to the opamps and to the transistors from the output stage.


1 KHz perfect sinewave

Nevertheless, this is one of the best Hi-Fi equipment for PC's where opamp rollers can successfully test their preferred opamps in I/V, LPF and Voltage Amplification stages. I've successfully tested myself lot of opamps without issues: BURSON SS V6 Classic & Vivid, BURSON SS V5, BURSON V5i, NE5532, LM4562, LME49720, NJM2114, OPA2132, OPA1652, OPA1602, AD8599, AD8672, MUSES8820, MUSES8920 etc. However, you need to take very good care of opamp "polarity" (pin1 should connected correctly) and try not mixing single with dual opamps or vice-versa (respect Burson's included schematic).

Variable volume control makes possible interconnection with active monitors/speakers, so I've took the opportunity to connect my Mackie MR6mk3 monitors and the MR10Smk3 subwoofer. Besides the volume potentiometer no other adjustments were needed, just plug and play and output sound was perfect into my ears, no EQ or DSP filters needed...it just sounded right from the 1st second. However, volume level was setup around 42% to get the desired 2V RMS on PLAY's RCA outputs, so I can correctly feed my Mackie speakers.

Using SS V6 Vivid in all DIP8 sockets sound gets more upfront, especially women vocals, but also the cymbals. If low-bitrate MP3 are going to be listen then prepare to hear every little encoding imperfection, because these opamps are more crispy and detailed oriented, but without harshness.

The SS V6 Classic are a bit more laid-back, with a detailed and a bit larger scene, totally neutral and very good for monitoring. The SS V6 Classic I liked most in the pre-amplification stage, so I intend to use them from now on all my devices on voltage amplification stage (already using with success it in my Matrix M-Stage HPA-3B).

Remote control is slim and fits nicely in my hands and the battery is easy to replace, based on the backplate that is kept in place by the 4 small magnets:


Remote control

There are accessories to connect the PLAY inside the PC case with ease, just unmount your PC, mount the below bracket, connect the included USB cable to your motherboard USB port. The included RCA-RCA cables are short and meant for use inside your PC to connect the RCA plugs of the PLAY to the RCA output bracket.

PC connection kit


Included gold-plated RCA cables

PLAY has a very good instrument separation, very neutral and with a good soundstage, not huge but also not very intimate. The final sound can easily get changed by swapping the opamps, so feel free to add your own flavor here.

CONCLUSION: Probably the best and the only DAC/headamp combo designed to fit inside a PC case that is using a XMOS chip for USB transport and a fully discrete Class-A amplifier. At least I'm not aware of any other manufacturer providing such a powerful amplifier for a PC soundcard/combo. Most manufacturers are relying on integrated opamp output buffers, which is fine, of course, but under no circumstances would compete with a 2W Class-A transistors output stage.

Note: I don't have a perfect tool to do the noise measurements, but my good old ASUS U7 has a really low-noise ADC (around -110dB).

Latter Edit #1: I am adding a new image with the new PLAY version created by BURSON: PCB revision 2.2. In respect with some of us that prefer listening to very sensitive 16-32 ohms cans, BURSON was able to create new PCB revisions (v2.1 and v2.2) that are having a lower background noise to better accommodate with sensitive headphones.



I've also tested the Basic version of PLAY (rev. v2.2) that costs only $299 and I realised that this is the best buck for the buck at this moment. Actually, I'm not aware of any other external USB DAC with such a powerful Class-A headphone amplifier at <$500, hence my initial rating of 4.5* is getting upgraded to a clear 5*. Great job BURSON!

Latter Edit #2: In the past couple of weeks I was testing latest available std. version of PLAY with Hifiman HE-560 headphones and I must say that lot of synergy is there. The powerful solid-state output stage can easily drive these planar cans even when listening at lower volume. When moderate-to-high volume is used, bass is striking with authority, but without impacting the mid-bass or the midrange in any ways. Seems than both planar cans tested in my review (Fostex TP-50RP MKiii and Hifiman HE-560) are a 110% match with PLAY, so I can strongly recommend the PLAY for use with planar headphones, because it is able to drive them at least as well as it does with dynamic cans too.

Hello,
 
Thanks to Charles from BURSON I've done some tests with my ASUS Essence One MUSES BURSON MKii DAC by upgrading existing opamps with V5i received recently from BURSON (thank you BURSON for providing me the chance to make this test).
- WASAPI was used instead of ASIO (don't trust ASIO for this test)
 
Music used for the tests:
- ATB
- Kenny G.
- Best of Chesky
- Head-Fi And HDtracks
- Ultimate Demo Disk
 
Headphones used for the tests:
- AKG K701
- AKG K550
- Beyerdynamic DT880/600ohms
- Grado SR60i with L-cushion
- Apple/Beats Solo2
 
Results:
- When using 2 x V5i in Low Pass Filter and 2 x V5i in Voltage Amplification Stage (from headphone amplifier) difference was noticed from the very first second:

1.   first impression was like volume is louder than before (which is not, measured three times with my scope and with RMS-multimeter)
2.   stage is larger and layering is better
3.   bass seems a bit more "rounded", with better definition, a good improvement for "bass shy" headphones (ATB bass and imaging can really shine with V5i opamps!)
4.   Kenny G.'s saxophone stands out a bit more with V5i and layering is way better, same I can say about staging/imaging

 
The V5i dual op-amps could be also used in output buffers too with great success; I couldn't find a real difference to talk about here, although it's been a small difference in sound tonality that can't explain it very well (nice pleasant warm sound).
 
There was no overheating for V5i, actually when used in the output buffers and in the gain stage V5i were barely warm to touch. When used in low-pass filter stage the V5i were about the same temperature as by MUSES01 from the I/V stage are (a bit over 45C with case open).
 
I've also attached some pictures to reflect that using V5i opamps in LPF, VAS and also in output buffers is not inducing any oscillations or odd harmonics (tough I don't have access to Audio Precision equipment, I've used a decent scope to test this). Screenshots where taken while using my PicoScope 2204A connected to MacBook Pro laptop with default probe connected to Essence One headphones output, -3dB test signals and volume button to about 10 o'clock.
 
 
PROS:
- Soundstage
- Sound neutrality
- Brings more details upfront
- The outside metallic case acts like a EMI/RFI shield (for the SS V5 opamps you needed to purchase additional copper foils and ground it separately, but that's not the case for the V5i opamps)
 
NEUTRALS:
- Size is a bit bigger than a regular DIP8 opamp and may not fit everywhere.
- It would be great for BURSON to create these opamps for devices having +/-18V on the rails. Right now V5i are designed with +/-16V in mind, but a native V5i able to be powered from +/-18 would be great if we could all have it in the future (like the older SS V4 that can be powered up to +/-20V).
 
CONS:
- May not be compatible with all devices out there, some people reported on Head-Fi some hiss/noise issues when used in voltage amplification stage. This happened to me with Matrix HPA-3B when using gain of +5dB, though when using +10dB or +20dB the V5i were shining and singing with great soundstage and lot of details. So, dropping one star because of that.
 
Regards and happy modding, 
Raul.