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Desktop Amps item created by morphon, May 11, 2010
Pros - Good sound at a low price. Lots of easy modifications.
Cons - Started making static noises after about 6 months. Failed completely not long after.
I enjoyed the sound from the Bravo Audio v2 amp, while it was working. Driving PSB M4U-2 headphones (with internal amp off), the sound was relatively open and uncolored. I found the two LEDs annoying and would have preferred to see only the tube's warm glow as a pilot light. Unfortunately for me, my unit started making static noises about 6 months in; the blue LED would flicker with the static. Two months later, the unit is completely dead. Only an occasional small pop comes out. I guess you get what you pay for.
Pros - Clear Sonic Presentation, Rolling Capability, Driving Power, Value
Cons - Heat Emission, Open Case
Me: I am a 21 year old student living in a small town in India. I would like to call myself a music enthusiast, rather than an audiophile. I was inspired by music since childhood, and as the time passed, the passion of music grew in me, and that subsequently led me to join Head-Fi. Eventually, I found the pleasure of listening to music mainly by the HD600 and recently, by the seductive LCD2 headphones, and realized the true components of recorded music. I usually like to listen to Indian Classical Music along with Bollywood songs. My main listening genres include classical, vocal, instrumental, jazz and sometimes pop. With time, my sonic preferences have very much grown. I avidly admire transparency, accuracy along with neutrality, and currently my favorite headphones are K702, HD800 & K812, which I mainly run from my trusty M-Stage HPA-2.
Intro: Bravo Audio is a popular Chinese brand specializing in the area of tube headphone amplifiers in economical price. Bravo was established in 2010. Even though a relatively newer establishment in the field, Bravo managed to capture attention of the world by their amp offerings which had attractive price tag & appreciable performance. Back in 2010, tube/hybrid amps would be expensive, and out of reach of a humble Enthusiast. Bravo made well performing hybrid amps in an affordable price. Bravo was the one who made hybrid amps in sub 100$ category. This made them a well known name across the Audiophile World.
All of Bravo’s amps are hybrids, and are driven by Mosfet’s, and are pure class A. This ensures in mammoth output power, appreciable clear sound quality, but heat dissipation is high, and the amp physically gets hot even to touch comfortably. Bravo has been famous since its release of V1 (6922) & V2 (12AU7) amps, which were budget friendly, yet performing, which won ears of many enthusiasts. The V2 employs Shuguang 12AU7 tube. Both V1 & V2 are very similar in design, features & functions.
Specifications of V2:
Input Power: DC 24V 1.5A
Input Sensitivity: 100mV
Input Impedance: 100KOhm
Headphone Impedance: 20~600 Ohm
Frequency response: 10Hz-60 KHz +/- 0.25dB
Signal/Noise Ratio : >90dB Gain: 30dB
THD: 0.016% (300 ohm) 0.45% (33 ohm)
Let us see what the V2 amp has got for us,
Packaging and Accessories: The V2 amp arrives packed inside a general cardboard box, packed inside a removable foam packing. Packaging is generic, but nothing to complain about. But all the included accessories have a good quality and feel to them.
List of accessories in the box, which include the following:
Power Adapter: AC to DC 24V 1.5A power adapter EU/US/AU/UK is supplied as per specifications.
¼” Converter: A 1/8” to ¼” converter for headphones with 3.5mm Jack.
Design and Build: The V2 has a very good overall build quality. Though it is enclosed in open acrylic sheets to save manufacturing costs, it gives out funky DIY looks. The V1 looks much different& funky, and stands out from the crowd. Even then, the open case is of good quality transparent fibre & metal supporting beams. The transparent sheets make us gaze through it and onto the well soldered circuit board. The V2 is fairly small in size The V1 is light in weight, & weights under 250 grams.
At the front we have volume knob, ¼” headphone output socket & a 3.5mm input socket. At the rear side of V2, we can observe the presence of power socket & on/off toggle switch. Volume knob rotation is smooth and knob has just the right size for fingers. ¼” jack is also a very sturdy, but is slightly tight. The ¼” socket employs clip mechanism, which may cause scratches/damage on the headphone jack. Power switch has a good switching feel and strength, and is very precise in its job.
Internals quality is certainly good. The V2 amp has no manual wirings; everything is fixed on the PCB. Soldering & joints are very well done. Volume pot is well known Alps branded, which a plus for both volume control & audio quality. Please do note that the Mosfets run very hot, be sure not to touch anywhere near them, otherwise burn injuries are guaranteed!
Since the V2 amp follows Tube/Mosfet Hybrid design, there is a 9 pin vacuum tube socket present, in which we may roll any compatible 12AU7 family tubes. The default one is 12AU7 from a Chinese brand called Shuguang, & does a great job in sound quality. There is a blue LED below the socket, which gives out a glow effect to the tube.
I observe a drawback in the power supply, it is not earthed. I am at a loss of understanding why Bravo did not include a third earthing pin or ground to make the amp safe. Since it is a DC supply, few ripples will be present in the final output. These either cause light electrocution/sock or audibly raise noise floor of the amp. All Bravo amps use the same 24V 1.5A power brick, and are not grounded o earthed. So if you happen to find a better quality laptop power supply within this specification, then it is a plug in replacement or upgrade.
Sound: The V2 amp delivers ‘Clear’ sound as a typical entry level tube amp and goes in the line of Bravo’s ocean amp. Presentation is in such a way that, mids are little more intimate, with lows & highs sound tad more relaxed and laid back.
Burn in: I could not notice any major improvement by burn in. But let’s say a playback of about 20 hours provides few minor audible improvements, Bass prior to break-in is quite muddy & loose, and eventually it becomes a little more accurate and clean, Mids will sound more open & slightly forward, airy and natural. Highs become slightly smoother; soundstage will open up by a margin.
Tube rolling: One can roll enormous number of 9 pin 12AU7 or equivalents. After much testing a few tubes from different, I could conclude, the stock 12AU7 is indeed very good at its job, is optimal for the existing circuit parameters. But tubes like Mullard or RCA brands also do provide a more pleasing sound. Replacement of stock tube is not absolutely necessary.
The gain is fixed at 30dB, which is on higher side and is certainly not recommended for IEM’s. This amp is extremely powerful and can drive any dynamic magnetic cans to insane loudness with just 40% of the volume used, which is at 11 o’clock. Anything above 12 o’clock is unbearably loud.
Lows: are fairly accurate, are slightly on ‘looser’ side; but have a good impact. Depth is decent.
Mids: Forward & intimate, are smooth and feel natural.
Highs: Spacious, but not detailed.
Soundstage: decently airy & spacious. For anyone who is looking for a good soundstage definition in entry level tube amp, V2 is a satisfactory performer. But one should not expect sonic qualities like detail retrieval, accuracy or good imaging from this amp, owing to its economic cost & the V2 is one of the cheapest available tube amp today.
Overall, final sound deliverance is decently satisfactory for an entry level tube amp.
Comparison: Bravo’s own V1 amp can be compared with V2, owing their vastly similar design & functions. Also, the price different is mere 10$.
Bravo V1: Same functions, features & design, and sonically is slightly inferior by sound. The V2 is more neutral, provides a much cleaner sound output with good soundstage definitions, when compared to the V1. The added bonus here is The V2 costs 10$ less than V1.
Verdict: The V2 edges out the V1 with overall better finer accuracy & neutrality in sound, finer power distribution.
Conclusion: Sonically, Bravo’s V2 amp performed well & has pleased me for a tube amp available around 70$. The V2 is a good performer owing to its 12AU7 architecture. This would a friendly amp for any enthusiast looking for a decent low cost tube amp.
1) Build Quality: even though it is open by case, the V2 has a very good interior build. No compromise to be seen anywhere in exterior too. Circuitry is also neat & well built.
2) Rolling Capability: Enthusiasts can roll great number of tubes to alter the final sonic signature.
3) Driving Power: The V2 amp has a sheer output power. It definitely can comfortably drive any set of high impedance cans.
4) Sound Quality: Is satisfactory considering its price, & performs upto expectations.
4) Value: Considering the above points, the V2 amp will have a solid price/performance ratio. There is no such tube amp which can perform better than Bravo V2 under 70$.
1) Heat emission: Actually not really a con, it is quite normal for a hybrid mosfet driven amp. But during operation, the V2 amp gets very hot; it becomes very difficult for a user to touch the surface of amp more than 2 seconds. The mosfet heatsinks, which are exposed & are very hot.
2) Power Supply: The default power supply is not grounded, hence a fair change of light electrocution and audibly higher noise floor. Thus one needs to earth it by connecting the input cable to a grounded source (like PC, which will be earthed)
Pros - Affordable; attractive aesthetically; sounds decent with mods
Cons - "Pseudo-tube" amp; requires mods to sound decent (low quality stock components)
The Bravo V2 is an attractive and inexpensive "pseudo-tube/hybrid" amp that is easily accessible to beginner DIYers if modifications are desired (which they definitely are as I will expand on later).
I'll review both the stock unit as well as modified amp although the star rating is for the stock unit. The modded unit would be a 3.5 - 4 star rating.
The V2 is a small desktop amp (8 x 8 x 3.5 cm approximately) with exposed sides and a clear plexiglass top and bottom plate. It is very attractive and easy to access for mods, but that's where the build/design strengths end. The PCB is very cheap and the stock components are very cheap. For example, the amp is powered by 24V but the power cap is only rated at 25V, leaving little room for overvoltage protection. Replacing this cap with a 35V cap is good preventative measure. The is also a sound popping sound upon power ON, which can be fixed with an induction coil and relocation of the switch; I'm no electrical engineer, but this is bad circuit design I would think.
The blue LED is obnoxious in my opinion and is an eye-sore. You can either short it to turn it off or replace it with another LED of your choice.
Also, this is what many consider a pseudo-tube amp since the tube itself does very little of the amplification and is largely used a pre-amp stage for coloring/warming the sound. Other hybrids utilize the tubes a bit more and pure tube amps run crazy high voltages.
The stock unit does not sound very good. The highs are muffled and there is noticeable distortion. Bass heavy songs sounded OK, but everything else sounded muffled and harsh with none of the warmth you might expect from the tube preamp. Replacing the stock tube will help the sound, but the real fix is to replaced the stock IRF630 voltage regulator with a IRF510 or IRL530 regulator instead. This extends the highs and also seemed to reduce distortion. The heat generated form these upgraded regulators however is higher, so it may be wise to upgrade the LM317's to LM317A's as a preventative measure. After switching to an IRF510, the heat sink measured 70-75C after 30 minutes of operation (I used an IR laser thermometer). Replacing the output caps with 25V/2200uF caps are said o improve the lower frequencies, but that's debatable depending on who you ask.
At under 70USD, this is a great way to get your feet wet when it comes to DIY audio devices. If however, you want bargain sound under 100USD without doing any mods, go with a solid state amp like the Schiit Magni or a FiiO E-Series amp.
In closing, I think this is a nice introductory amp although the sound quality was never stellar even with a full suite of modifications. As I mentioned earlier, this is a great DIYer's amp although the cheap PCB is terrible for desoldering. It would be great if this amp was offered as a kit for home assembly (that way, you only need to solder once and include any upgraded components the first time around), which would further drive down cost.
Pros - Inexpensive, easy to tube roll
Cons - The stock tube really sucks
In the world of Budget-Fi audio, there is a relatively small set of amplifiers that can be purchased for under $100 USD, and an even smaller set of amplifiers in that price range that are hybrid tube amps. The Bravo V2 is one of those amps. It can be purchase on auction from eBay for about $50-55 (depending on how many people are bidding), or at a fixed price of $69 from either Amazon.com or eBay (the seller/manufacturer on eBay ships from China and charges $16 for shipping that takes about 2 weeks to the US).
By many accounts, this device was designed using DIY project specifications readily available on the Internet, which have existed for some time. Those who purport to know much about these things say that it's not a particularly sophisticated design, and requires numerous modifications to really sound good. Some even question whether this is truly a Class A amplifier.
On the other hand, whaddya want for $69 bucks, bro? This isn't a Bottlehead Crack, or a Schiit Valhalla. It's not made in a numbered garage either (though the residents of that numbered garage seem to spend an inordinate amount of effort slamming this little product, and have become so annoying to me that I've decided to never, ever consider their products, for any reason, under any circumstances). If you're shopping for an amp in this price range, then the driving factor really is your budget. So we're talking bang for the buck here. All comparisons to more expensive devices are pointless. Yes, you can buy better amps, but so what?
What this is, is a really cool little amp that sounds damn good for $69 bucks. I own two of them. I'm going to mod one of them soon, and write a comparison of them when time permits. (Oh, don't preach to me that I could have bought X or Y for the price of two of these devices. I want two amps for two different locations.)
But, really, you need to get rid of the stock Chinese tube. Quickly. Okay, you can listen to it while you're waiting for your American NOS 12AU7 / 5963 / 5814 (etc) tube to ship from eBay. Unless you're really filthy rich, don't waste your money on a Mullard or Telefunken (which can easily cost more than this amp).
I've written a comparison of this amp against a Schiit Magni here. I've also made some tube rolling notes in this thread. In short, this cheap little hybrid amp sounds pretty darn good for the price, and I don't think there is anything in its price range that can compete with it, short of a Schiit Magni. Quite frankly, which one wins depends on the cans you're using, and what style of music you like to listen to.
Some day, I think it would be interesting to get or make a cMoyBB, just to make sure that this is better. To date, it hasn't been that important. Portable amps aren't really something I use. But I am curious. So maybe someday.
I highly recommend this amp to anyone who has $100 bucks to spend on a headphone amp, wants to have a tube type amp, and isn't shy about using eBay to purchase an accessory. Do NOT buy any 12AU7 replacement tubes from Amazon - they are all junk. If you don't want to use eBay, or don't care about tubes, then buy a Schiit Magni. The Magni is an awesome amplifier, hands down. It's just not a tube amp.
Both amps are outstanding values in this price range. Neither one of them is really "better" than the other - it's personal preference in this range.
Pros - Price, looks, size
Cons - Hum is audible over music at only 45% volume, rendering it unusable past this point. Died on me after only 20hrs of use. Poor support.
Edit: My V2 has recently began to produce a constant pulsating static noise that persists as soon as it's warmed up, and never goes away. It is loud enough to be audible over music, but does not seem to get louder with volume (like the hum). The issue persists even with volume all the way down. I am currently in communication with Bravo support (Henry) via email about this.
Edit2: Henry sent me a replacement power supply but both issues persist. After filing a dispute in paypal he has given me a full refund. He failed to respond to me until I filed the dispute. A bad product with poor support, I do not recommend buying anything from Bravo Audio.
Edit3: Due to the quality issues this has been sitting unused for several months. I plugged it in the other day to show a friend and it would no longer power on. Completely dead after only 10-20 hours of total use on it.
Used primarily with my Sennheiser HD 600. The DAC being used is an X-FI Fatality Pro. I also own a Fiio E11 which I will make some comparisons to. This product pretty much stands alone in it's price point for Tube amps ($70). In this price point, most solid state amps have considerably less power. An impulse buy I just couldn't resist.
In the box you get the unit itself, with the tube installed, safely packaged, with the power supply and power cord. No manual or documentation was present, but each I/O is clearly labeled IN/OUT. It looks and feels solidly built, besides some glue like residue I had to remove in places. A minimalist design at only 3 inches square, fits perfectly on a crowded desk. The blue LED lights at the base of the Tube look great, not overly bright in the dark. Inputs for RCA or 3.5mm. Output is 1/4 inch (6.5mm). Volume knob feels solid, and does not distort or add static when adjusting. However, the unit does get very hot to the touch, particularly on the two black heat sinks on either side. It seems to get the warmest after about 30 mins of use, but never gets hotter, even after several hours. This is likely normal for most Tube amps, specially compact ones like this.
First I would like to say that volume was adequate at 60% with my HD 600 connected to my X-FI directly. So with this purchase I was expecting to get a bit of an introduction to the Tube sound, with some extra power when/if I need it. When listening to the Bravo V2 under 45% volume, I did get a hint of warmth and a more present mid range, without missing anything in the bass or treble. The sound stage and detail, although good, was no real improvement over the X-FI directly. The Achilles heel of this product is that it cannot be used beyond 45% volume. The hum becomes audible through the music beyond this point.
At first I thought I had a ground loop issue causing the hum, but I confirmed it was the amp by testing it with a battery powered laptop. My X-FI has no audible hum until about 80% volume, and even then it is not enough to be audible with music playing. Maybe I was spoiled with my Fiio E11, because this thing sounds dead silent even at 100% volume, not to mention it's more compact, and has a gain switch with bass boost. Compared to the Bravo, the Fiio is more flat and sounds much cleaner at higher volume, despite having less overall power.
To be fair, I only require more than 45% volume on the Bravo when my X-FI is at 40% or less. If I up my X-FI to 60-70% volume, I require no more than 20-30% volume on the amp. With this configuration, volume is much higher than the X-FI can produce alone, so I would never "need" to go past 45% on the amp. However, I wanted to let the amp do to the work, so I could hear the warmth of the Tube sound come through more. I also like to know that the extra power is there if I need it for future setups/headphones. Unfortunately, this was a big let down for me. If your considering this amp with anything over 300ohm impedance, look elsewhere.
When used under 45% volume, sound was still no real step up from my X-FI directly. I could of lived with this, if I could have used at least 70% of available power. Maybe my expectations were too high for a product in this price range. I realize Tube amps generally have more distortion and lower SNR than their solid state competitors, specially in the lower price ranges. Regardless, I can't recommend an amp that is only 45% usable, even in this price range. If a product cannot operate properly at the higher specs, it should be designed "within" the usable power band (like the Fiio E11). I can't stand behind a company or product that is advertised to tow 3 tuns but falls apart after 1.5. In hindsight, I wish I had purchased something like the Fiio E10/E07k, or even the Schiit Magni (a mere $30 more). For those hoping for a good cheap introduction to Tube sound, keep looking. The bottom line is, you can do much better, even at this price point. They call this a "Class A", I give it a D minus at best.
Pros - Everything
Cons - Stock components suck, the design is not optimal.
I got this small amp from a local marketplace. It sounds OK when I got it, too warm, almost no treble.
After I got the schematic and tips from google I did some mods with this baby and now it sings!
What I did:
1. Cut some traces for crosstalk improvement
2. Make better grounding, measure voltage difference between in and out, make sure its not more than 1mV
3. Change the power supply filter cap to low ESR Panasonic 3300uF, 35V
4. Change 2 output caps to low ESR Panasonic 2200uF, 25V
5. Change 2 N Channel Mosfet to IRL510
6. Install 2 5K ohm pots and adjust tube biasing to 13.5V.
7. Install ferrites clamp on the power supply cable
I'm using it with my DT880 600 ohm, it beats XCAN V8 when I compare it in my local "fancy" hifi store. The owner of the shop was really surprised when I said the price was 60$ + 20$ for extra components.
Pros - Good quality build and sound quality
Cons - None..built for its purpose and does it well
I use the Bravo tube amplifier as a pre-amp on my jaycar power amplificator and it has revolutionised the sound output. Whereas before the sound was sctrachy and the max volume low, the system now works brilliantly. Vey happy customer and would recmmmend to anyone who wishes to purchase a headphone amplifier or pre-amp.