Burson Audio Bang (29/8ohms, 40w/4ohms, PC, Class A/B Stereo Power Amplifier)

Discussion in 'Computer Audio' started by raoultrifan, Jul 19, 2018.
  1. raoultrifan
    Hello,

    Couldn't find a dedicated thread about this power amp, so starting a new one here where I will be posting some thoughts, pics and some in-house pictures and measurements.

    Meanwhile, some details about this power amp taken directly from the manufacturer.

    Burson-Bang-S1-2.jpg
    Burson-Bang-S2.jpg
    Burson-Bang-S4.jpg
    Burson-Bang-Ext2.jpg

    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

    So it will fit perfectly inside a regular desktop computer. This should probably make it the first Class A/B power amplifier that perfectly fits inside a regular desktop computer...well, at least I'm not aware of any company building something like this before.

    I am considering this design and the 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, beautiful and strong, able to deliver enough power to drive our speakers inside our 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.

    Per design simplicity, BANG has no volume knob, so please use an audio source with built-in volume control or a pre-amplifier between your audio source and BANG!

    Mains power supply delivers 12V/120VA 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.

    Inside pictures, details about the design and some in-house measurements will come soon. Meanwhile I am enjoying the weekend by listening my preferred music to BANG and my old PIONEER speakers. :)
     
    selvakumar likes this.
  2. raoultrifan
    I was measuring today the DC offset voltage at outputs, without input source connected, and got the following figures:

    With 2 x SS V6 Classic dual connected I got:
    • after power-ON: right 60mV, left 50 mV
    • after 5': right 33mV, left 26mV
    • after >4h: right 28mV, left 21mV
    With 2 x NE5532 connected I got:
    • after power-ON: right -18.5mV, left -21.8 mV
    • after 5': right -18mV, left -21.3mV
    • after >4h: right -17.9mV, left -21.2mV

    With MUSES8920 connected I got:
    • after power-ON: right 0.9mV, left 1.9 mV
    • after 5': right 0.7mV, left 1.6mV
    • after >4h: right 0.4mV, left 0.9mV

    With all op-amps tested the DC-offset voltage is very low for such a powerful amplifier, so I consider this very-low DC-output a highlight for BANG, especially that there are no capacitors in signal path! (see L.E.). Usually, less than 75mV of DC-output is considered a good value (e.g.: 20mV means 0.00005W@8ohms, that's about one millionth of the max. power of the chip, so definitely a very low figure). 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!).

    However, per Texas Instruments LM3886TF datasheet http://www.ti.com/lit/ds/symlink/lm3886.pdf, page 14, seems that with 4 ohms speakers the max. power would be a bit higher than BURSON's recommandations:

    BANG_output-power.png

    It is indeed 29W @ 8ohms, but for low-impedance speakers I see on the datasheet a max. power of about 55W @ 4ohms per each channel! Also, @6ohms the output power seems to be around 39W @ 6ohms, which is an impressive value for this small sized Class-AB amplifier.

    What would be the reason BURSON is only labeling it @40W/4 ohms instead of 55W/4ohms? Well, it's easy, given its small size, BANG's aluminum case can't dissipate so much heat to sustain a continuous 2 x 55W/4ohms. So, even if BANG could theoretically get to a more output power, we should never push it further unless we want the >100C thermal protection to kick-in and stop the output sound until the two LM3886TF chips will chill-down...though it's good to know there's some reserve power left over in there...you never know when some lunatic might try modding it and, of course, loose the stellar 5 years warranty. :) Seriously, not recommended, just keep it within BURSON's specs!

    Speaking about temperatures, I was able to measure a maximum temperature of about 50C on the two LM3886TF chips, inside my room air temperature was 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.

    L.E.: Immediately after the 2 x RCA input plugs there are 2 x 47uF ELNA audio capacitors, one for each channel, (almost 5 times bigger than TI recommends) for the purpose of cutting any possible DC-voltage coming from the input source. Given their big capacitance, there is no bass roll-off at all, even down to 20Hz.
     
    Last edited: Jul 22, 2018
    alphanumerix1 and selvakumar like this.
  3. raoultrifan
    The design is pretty straight forward, the dual op-amp is used as gain-stage, 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. That makes this power amplifier a very good equipment to swap op-amps and this is good thing for most head-fiers. :)

    Choosing between the default NE5532 and BURSON op-amps could change the sound flavor a bit, depends on everyone's ears and speakers. You can swap here every dual op-amp you want if it's designed for audio use, otherwise please check the datasheet of the op-amp or consult BURSON technical support for op-amp compatibility. A defective op-amp or an 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 op-amp is powered by dedicated LM7812/7912 linear regulators, so op-amp's voltage would be +/-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.

    Between the op-amp and the output stage there are two gain switches, one for each channel, that help us to choose the proper gain for our speakers, based on the input signal voltage.

    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 load with ease. The 120VA SMPS power supply has enough power reserve to boost the bass instantly into our speakers.
     
    Last edited: Jul 22, 2018
    selvakumar likes this.
  4. raoultrifan
    Some inside pics, for a better understanding of the technical reviewing. :)

    IMG_5191 copy.jpg
    The two linear regulators that provide power for the op-amp (+/-12V).

    IMG_5193 copy.jpg
    SMPS power regulators for the LM3886 right-channel

    IMG_5194 copy.jpg
    Top view with PCB and internal components

    IMG_5198 copy.jpg
    Output coils and resistors used to prevent unwanted oscillations

    IMG_5200 copy.jpg
    Top view with the two power amplifiers

    IMG_5201 copy.jpg
    The SMPS boost-converters and surrounding coils that take care of both power amplifiers
     
    alphanumerix1 likes this.
  5. raoultrifan
    A short notice, for those that might want to put this big-baby inside their PC case:
    - First you need to be 110% sure that your PC's internal PSU is able to sustain an additional 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.
    - Also, please take into consideration the amount of digital and analog "audio noise" your 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 you do have a low-noise powerful PSU, then you might give it a try, but otherwise you might want to stick to the original 12V/10A power adapter provided by BURSON.
    - The amount of heat generated by the BANG power amplifier could be higher than the amount of heat generated by your CPU (>100W of heat), so if you don't have a decent cooling inside your PC case you might not want to try BANG inside your 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 or bottom of BANG to suppress the airflow.
     
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  6. newdoughboy
    Nice info.
    Here are my initial findings.

    Setup

    Galaxy s8 - Bang V6 Vivid - Paradigm Atom v7 or Galaxy s8 - ParadigmShift A2, mp3 files

    Now comes the amplifier comparison; does classAB truly sound better than classD? Maybe it doesn’t need to be pointed out, but the internal dimensions between the A2 and Atoms are similar but not identical due to the different back plate and the integrated amplifier. The simple answer is an absolute YES.

    From the first song Somewhere-WIthin Temptation Black Symphony duet, I can tell there’s something special about the Bang. I hate to generalize it, but it sort of mimics my finding when comparing IC opamps to Burson discrete opamps. The Bang makes the sound very welcoming and envelopes you in a musical experience. The A2 gives you enough detail and power, but the Bang smooth out the semi harsh highs to create a more comfortable listening environment. The soundstage is more 3 dimensional, and the layers of voices and instruments just blended more naturally with the Bang. There was just a little feel of graininess that the classD amplifier reveals.

    Second song is Boom Clap-Charlie XCX, which is my classic car audio benchmark song. It is a simple show of electronic notes with lots of bass. This revealed that the A2 has a bass hump that is probably designed for young audiophiles. This song comparison surprised me quite a bit. The Bang produced a very controlled bass, which may not be the best for this song, but amazing for everything else that doesn’t require the extradurated bass. What surprised me was how involving the sound of from the Bang. Everything was so smooth and so much more detailed than the A2. The 3D electronic notes and lushish vocals were stunning. Hands down the Bang pair with the Atom is my preference; they almost sound like a different pair of speakers.

    To jump on the electronic train, the third song is Sphinx-Nora En Pure. This song has been my recent favourite for bass heavy trance. Of course everything was smooth with the Bang, however; I would pick the A2 for this song. It pushes the treble forward and boosts the bass. The classical move to increase energy of a pop/electronic song.
     
    raoultrifan likes this.
  7. raoultrifan
    I was listening yesterday through BANG to some 2017/2018 Pop/Dance music using as input source Lenovo X230, Lenovo T440, MacBook Pro 2015 and from ASUS Xonar U7 (only 1V RMS on RCA outputs!) and I'm really impressed by the output power, clarity and it's small size. After all, when not using pure sine-waves to test this small amp, it's case it's actually not heating up so much; I'll spin it a bit more this weekend and see if I can heat it a bit more, just need to see how can I get rid of wife and kid so I can increase the volume to the max for few more hours. :)

    When feeding the BANG from ASUS U7 DAC the volume was high enough, but not so high like when using PLAY or laptop's output, even with the internal gain to the HIGH position, but this is do to the only 1V RMS (2.828 Vp-p) output for the Xonar U7 DAC. So BANG amplifier if powerful enough, even when low-voltage input sources are used, like only 1V RMS (even when using my old Nokia phone BANG sound very powerful).

    A really nice thing I observed yesterday: I can actually use BANG as a HEADPHONES AMPLIFIER. :)
    Yes, indeed, it's output noise is so very low that with phones like Beyerdynamic DT880, AKG K701, FOSTEX T50RP -k3 or Hifiman HE-560 there's absolutely no noise heard out of it, it's dead silent!
    I was comparing BANG with my old Pioneer A-209R discreet amplifier and with this one I was able to hear some noise with all the headphones from above. However, I estimate that Pioneer A-209R is having a background noise of 3 times x BANG (subjective test done with a bit more sensitive cans like Grado SR60-i or Beats Solo2).
    So BANG can't be used with IEM's or sensitive cans (not just based on it's internal noise, but more related to its' insane output power when driving these kind of headphones!), but I can actually recommend it for non-sensitive cans (depending on the gain choose, that means 4W - 5W when driving 50Ohms cans and almost 0.5W when driving 600Ohms cans, so quite good for those needing to drive Hifiman HE-5 or HE-6 or high impedance cans). It's output power for high impedance cans is actually similar with amplifiers designed by Lake-People, Violectric and others (>15V output voltage), but when pairing BANG with low-impedance cans then ears and headphone could get broken instantly!

    Notice: Please don't try to power your headphones from BANG directly unless you use a volume adjustable input source like PLAY (lower the knob to about 15% or so). My above paragraph is meant for those that really need to drive very hard to drive cans only!

    L.E.: 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 big sound when paired with BANG.
     
    Last edited: Aug 3, 2018
    alphanumerix1 likes this.
  8. Eiffel
    The only downside of the Bang, if I can say this, is that he need a source with a pre-amp.
    It was designed with Play or Fun in mind. Of course there are some other DAC's with volume control on their Line Out.

    However it would be great if they could made an pre-amp only and with input selector to use with Bang. I would buy this - for desktop use only, but I really need at least 3 inputs. I don't like to change cables each time I change source.
     
    alphanumerix1 likes this.
  9. newdoughboy
    That's a good point. At least my Burson soloist has 3 inputs.
    20180802_103153.jpg 20180802_103207.jpg
     
    raoultrifan likes this.
  10. selvakumar
    my psucan support any thing and im buying it now
     
  11. raoultrifan
    Great Selva,

    Here're some pics from my test setup, see below.

    WP_20180725_09_40_24_Pro.jpg AdobePhotoshopExpress_9672ad5687ea41cba8e853cec98fa43e.jpg
    AdobePhotoshopExpress_0e038520b7f64c58ae2da7c4b30cb2ba.jpg AdobePhotoshopExpress_de1eeb5f2ace46d0b7751a80d99ddb74.jpg

    And all 3 devices paired together:
    AdobePhotoshopExpress_aad337ad202d46dd974acca187a09ffd.jpg

    So 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 (very low 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 (very low music, no much power drawn)

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

    However, before pushing the power to BANG, please use a temp probe or something to test BANG's temps properly.

    Note: BURSON does not recommend BANG to get installed inside a computer case, because under most circumstances it might get overheated!
     
    selvakumar likes this.
  12. selvakumar
    Nice look mine
    Core i7-6950x 10 core
    Asus Rampage V Extreme Edition 10
    Dual Zotac Gtx 1080 Ti Amp Extreme in SLI
    Corsair HXi 1000 platinum power supply
    i love air cooling a lot with lot of Noctua Fans
    Samsung Nvme 970 pro 1TB and 2tb of Thosiba q 300 pro 10 th wd black
     
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  13. selvakumar
    upload_2018-8-5_11-28-28.png
    My rig
     
    Last edited: Aug 5, 2018
    raoultrifan likes this.
  14. alphanumerix1
    Ok burson you had my interest now you have my attention. After using the burson v6 op amps I've been impressed by there latest offerings. I'd love to get my hands on the play/fun/bang
     
  15. DjBobby
    Just got the Fun + Bang combo in the basic version. Also have some spare V6 Classics to experiment with. The review following soon.
     

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