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Amp/DACs item created by goldfingerfif, Mar 11, 2012
Pros - Excellent price, solid build quality, sound quality is clean and pure, 3 band passive EQ
Cons - Minor interference (EMI/RFI) due to no shielded case, but easy to avoid/fix
This is a wonderful little tube amplifier for the price. I paid only $59 for the amp and it was in perfect condition with a new Electro-Harmonix 6922 tube. The tube itself runs about $15, so the actual cost of the item was only roughly $45 (minus the tube). For that price, it is a well made, extremely well priced amp, and the value you get is superb.
Initial impressions - the amplifier is a more "DIY" open design, with no shielded case. This is fine considering the price. The actual build quality is great: solid soldering, and good quality parts. The gain potentiometer, for example, is an ALPS pot which are known to be high quality. For the price, this thing is built to a great standard. Doesn't come with very much extra: the power supply, amp, and the tube. Simple but efficient packaging. Two LED lights (blue and red, one signifies power - the red - and the blue is for the tube attachment, which draws voltage from the capacitor and can stay on for a few seconds after the tube is unplugged due to the capacitor holding some charge).
I've driven higher and lower impedance headphones. Most of my cans are low impedance, and this amplifier worked wonderfully for anything I threw at it. It states an output range of 20-600 Ohm, so that is pretty flexible with regards to driving cans. I don't have a pair of high impedance (600) cans to test with, however it should work fairly well for most cans on the market.
Sound quality is warm yet clean with no distortion or any real noise, which is something I would expect from a tube amplifier that is fully Class A driven. The amplifier comes with a 3 band graphic EQ, which is passive. This is pretty cool and adds some character and optimization potential to the amplifier for sure. Putting the settings all the way to max is basically the "0" setting since it is a passive switch; there's no "added" frequency adjustment, simply subtraction (not allowing certain frequencies through). Similar to a passive volume attenuator. So unlike a more traditional, non-passive EQ switch where the lowest setting is the default, the maximum up setting for the EQ is the technical default and lowering the switches simply attenuates the frequencies without distortion. This is a nice feature. Works well because you can adjust to your desire, and it's very flexible.
Amp can get a little hot, but this is expected, especially because this is an open case design. The heatsinks are what really get hot, which hold the rectifiers, which are power MOSFET's so they have a bit of heat. Nothing unexpected, just gets a little hot but nothing too crazy. I can still touch the EQ sliders just fine, but obvious caution should be applied as it is an open amplifier chassis. The tube itself is only somewhat hot; it is the heatsinks of the rectifiers that really bear the most heat load!
Since this is an open case, there is some EMI/RFI (electromagnetic/radio-frequency interference). This is solved by keeping things like cellular devices a few feet away from the amp, putting the amp in a solid, EMI shielded case (such as one made of solid aluminum or related materials), or placing it on a shielded surface. By doing this I easily get rid of the EMI/RFI. Part of the EMI/RFI is also due to the power cord, which is not grounded, but this is easily minimized to a significant degree with the methods I just mentioned as well.
Overall, I give this amplifier a 5/5. For the price to quality ratio, this thing certainly performs with flying colors. An excellent starting tube amplifier that gives the warm, crisp Class-A driven sound quality expected from a tube at a very accessible price point. Some photos below (click to see higher resolution).
Pros - Clear Sonic Presentation, Rolling Capability, Driving Power, Price
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.
Intro: Bravo Audio is a popular Chinese brand specializing in the area of Tube Headphone Amplifiers. 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 V3 goes ahead in V1’s line, providing hardware equalizing option and performance. The V3 is a unique hybrid amp design from Bravo, & it has a hardware frequency equalizer as a advertising feature, along with further improvements.
Specifications of V3:
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
Dynamic range: 84.6dBA (300 ohm) 89.8dBA (33 ohm)
THD: 0.016% (300 ohm) 0.45% (33 ohm)
MD + Noise: 0.045(300 ohm) 0.42(33ohm)
Let us see what the V3 amp has got for us,
Packaging and Accessories: The V3 amp arrives packed inside a general cardboard box, packed inside a removable foam packing. Default tube included is a well acclaimed Electro-Harmonix 6922EH, which is made in Russia. 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.
Electro-Harmonix 6922EH Tube: This is a good move by Bravo, this tube has a great build & is well known, popular in the tubey-world.
Design and Build: The V3 has a very good overall build quality. Its design is very practical. Though it is enclosed in open acrylic sheets to save manufacturing costs, and also for funky DIY looks. The V3 looks much different& funky, and stands out from the crowd. It looks more of a DIY-amp. 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 V3 is fairly small in size, but larger than the Bravo’s flagship ocean amp . The V3 weights only about 300 grams.
At the front we have volume knob, ¼” headphone output socket & an 3.5mm input socket, At the rear side of V3, we can observe the presence of power socket & on/off toggle switch. On the right of the V3, we also have RCA input option. If one input is plugged, other gets canceled. The Three Band Equalizer sliders are present on the top.
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 pretty great operation and strength, and is very precise in its job.
Internals quality is certainly good, if not very good. The V3 amp has no manual wirings inside; 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!
The Three-band equalizers slide very smoothly, no complaints here. The 9 pin Tube socket is ceramic type, has a great build. There is a blue LED below the socket, which gives a cool look in dark background. There also a red LED behind the tube socket. I sometimes wonder why there are two LED’s, one would have sufficed. There are no op-amps in V3, since it is a mosfet driven hybrid amp. The V3 accepts only the 6922 family vacuum tubes by default. But one can swap 6DJ8, 7308 without any issues, but the 6922 tube is rated at slightly higher voltage, so if you pop in the 6DJ8 (which require slightly less voltage) its tube life may reduce by a few hours. Also, the stock 6922EH is pretty great, thereby eliminating (or reducing) the need for rolling.
I also 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: Despite being a hybrid tube amp, the V3 has a very clean, clear yet airy sonic character. ‘Balanced & Enjoyable’ is the key word. I find it very appealing and pleasing for casual music listening. Presentation is in such a way that, mids are little more intimate, with lows & highs sound tad more relaxed and laid back. Surprisingly, Stock tube is pretty great and does not necessarily need to be changed/upgraded.
Burn in: These improve a lot with time. Let’s say a playback of about 20 hours provides few audible improvements, Bass prior to break-in is quite muddy, and eventually it becomes more accurate and clean, Mids will sound more open & slightly forward, airy and natural. Highs become slightly more smooth, soundstage will open up by a margin.
Tube rolling: One can roll 6922 family tubes on V3 amp. There are plenty of these tubes (and their variants, brands) for tube rollers. And the good news is that all these tubes are available within 10-15$ shipped on ebay! Another thing to mention is, there are trim pots which adjust the power supply balance to tubes, if a multimeter is in hand, please do tune them to perfection for different tubes rolled in. This is result in optimal supply for tubes and hence better sound. The default 6922EH is neutral and balanced. Amperex 6DJ8 which I tried had slightly more colour presentation with more natural but less neutral character.
The gain is fixed at 30dB, which is quite high and certainly not recommended for IEM’s. This amp is extremely powerful and can drive any dynamic/Planar magnetic cans to insane loudness with just 30% of the volume used, which is at 10 o’clock. Anything above 11 o’clock is unbearably loud. This incredible power brings out the best out of a matching headphone. Ideally, neutral or slightly brighter dynamic headphones go well with the V3 amp.
Lows: are accurate, tight and refined; have a great impact & extension. Depth is decent.
Mids: Slightly forward & sound very natural, and appealing, and have a slight warmth (I guess that is in a good way, comes very pleasing to our ears). Tonality particularly, one of the best at this price point. This character makes V3 a strong contender for classical music.
Highs: Very clear with desirable amount of sparks. They are airy with good amount of space sensation.
Soundstage: feels airy, natural and nearly-circular. Width is very good, & depth is fair enough for imaging. Instrument separation & detailing is pretty good. Initially, tonality is a bit harsh & mids are slightly sucked out (since the tube was new in box), But after burn in, its goes in great with the V3 amp. So replacing tube is not really necessary here.
Equalizer function: The given Three-band Equalizers work well, and are quite refined in function, does not feel bad or artificial at all. Just one thing I noticed that volume also increased along with the desired band when slider was slid upwards. It is the first time I have come across a band equalizer across am headphone amp. This is really a creative idea, but requires much better implementation & circuitry which would not be feasible here.
According to my observation, the V3 sounded good in all genres I tried, and hence I conclude, The V3 is decently transparent, detailed and also slightly forgiving to poor recordings. Hence I can say the V3 is an all rounder. It does not compromise anything too much to affect any of its characters.
Comparison: There is really not a worthy competitor for the V3 amp in this price of 80$. I have tried a few other Chinese hybrids like Little Bear, Indeed and many more, all are outperformed by The V3 amp. Though, a lot of excellent finished & more reliable amps Like Little Dot 1+, Schiit Vali & Bravo’s own ocean amps are priced around 120$-150$.
Conclusion: I feel the V3 is a unique hybrid amp in its price range. Build quality is good, sonic presentation is very pleasing, it can drive almost any cans & its sonic character can be tailored to meet one’s taste by tube rolling and equalizing.
1) Build Quality: even though it is open by case, the V3 has a very good interior build. No compromise to be seen anywhere in exterior too. Interior circuitry is also neat & well built.
2) Sound quality: Sound presentation here has a touch of naturalness, but yet is detailed, spacious, which is very much like-able for music listening. Sweet mids deserve a special mention. The V3 amp generally matches up well with slightly neutral to bright sounding headphones.
3) Rolling Capability: Enthusiasts can roll great number of 6922 tubes in a minimal cost.
4) Driving Power: The V3 amp has a sheer output power. It definitely can comfortably drive any set of cans from 20-600 ohms. Good job!
1) Heat emission: Actually not really a con, it is quite normal for a hybrid mosfet driven amp. But during operation, the V3 amp gets very hot, it becomes very difficult for a user to touch the surface of amp more than 2 seconds. The 6922 tube itself is just warm, It is the Mosfet heatsinks, which are exposed are hot & is due to heat emission from the mosfets.
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 - Fantastic sound, solid construction, good EQ
Cons - Open design may be a problem for some
I purchased this tube amp on eBay for 75 dollars in new condition. This is my first tube amp of any kind. The only other headphone amplifier I have owned is the Fiio E5.
First of all, I will state the entire listening set up I have that I use with this in order to provide a more solid frame of reference for the review:
My turntable is an Audio-Technica LP-120 turntable with the green stylus that came with it. It tracks at 1.5 grams.
I use a dedicated phono pre-amp rather than the internal one. The pre-amp I use is the Art DJPpre II Phono preamplifier.
For CDs I use my LG blu ray player's RCA outputs. When I listen to CDs I do have to turn the volume down as the CD audio is louder than what the vinyl set up outputs, but this is not a problem.
Finally, the headphones I use with this are Sony MDR-V6 headphones. They have an impedance of 63 ohms.
As different set ups can be better or worse for different genres, I'd like to state that my listening preferences largely are made of blues, 60s rock (The Beatles, Rolling Stones, The Animals, Jimi Hendrix, The Doors, etc), blues-metal/blues-rock (Led Zeppelin, Black Sabbath), heavy metal spanning from the 80s to now (ie, I like Iron Maiden, but also recent bands like Rammstein, Tyr, and Alestorm), and to a limited extent some electronic music (Kraftwerk). I also like a few punk bands, such as The Ramones, Buzzcocks, and The Undertones. I also like some miscellaneous other groups like R.E.M. and Rush. I have in fact listened to music from all of these genres since owning the amp & MDR-V6 headphones to get an idea of their versatility.
Overall, I absolutely love this pre amp. Compared to my FiiO E5 pre amp I feel like this provides a more natural and less harsh sound. Granted, these differences are marginal and not night and day, but I do notice the difference a bit. I also notice that CDs with more modern mastering sound better. CDs with clipping sound like the clipping is softened a bit which makes them more listenable. CDs & vinyl mastered with good dynamic range sound VERY lively. Loud sounds hit hard, and softer sounds are noticeable but not overbearing -- just the way good mastering should be.
I don't really use the EQ settings. I find that a flat setting gives the best sound. Do note that if yours arrives and the sliders are all at the bottom you need to move them up to the middle. Mine were at the bottom when it came and I thought that must be the flat setting (which I found odd), and quickly figured out my initial intuition that they ought to be moved to the middle were correct. In my set up, the bass notes hit hard and accurately. They don't rumble like those "beats" headphones. It's very precise. Some may not like this, but I enjoy the accuracy. After all, this amp DOES have an EQ if you want more bass. In any case, when listening to Kraftwerk's "The Mix" and "Minimum-Maximum" I found the bass impact more than enough. The mids sound great and natural to my ears, and the highs are not harsh, but clear and precise.
Inevitably, this review also ended up being partially about my headphones, as one cannot listen to a headphone amp without headphones. I can't really compare this to other tube amps since I have never had another tube device, nor can I state how it will sound on other set ups, but for me this is just perfect. I love it, and understand why others love tub amps (again, it's not a night and day difference, it's subtle, but there). If you have similar headphones, a similar set up for your turntable, or similar musical preferences, you may enjoy this. Do keep in mind that this is an open design so you will have to have a can of air to keep dust out of it, and make sure pets stay away. Another possible downside is that I noticed if I leave both the red/white RCA cables and the auxillary input plugged in the volume takes an audible drop by around 2-3 decibles, even if the other device plugged in is completely off. For this reason I only keep one device plugged in at a time.
Pros - Small, Loud, Clear, Tube/Valve, 3 Band Passive EQ
Cons - Only Passive Cooling, sometimes gains a little static
I don't have much to compare it against especially for headphones or as a preamp. I have used my Beyerdynamic DT860 headphones on my PC for a while and talked into getting a tube amp from a guy at my work. I thought I would try something cheap to get the idea of what a tube does to music. This one seemed decent and the other models had good reviews so I liked the idea of a EQ and purchased this one.
At first when I unplugged my headphones from my PC (Motherboard Sound card unfortunately, hope to be getting something more shortly) and the tube amp in with my headphones now connected to the tube I was surprised. I thought the music seemed muffled yet very little bass.
I was told to let it break in for 30-40hours. I let it play about 10hours before listening to it again so my ears wouldn't acclimate. It sounded more tinny now and I tried giving more bass with the EQ on winamp or with the passive EQ but it would just distort. It did sound better than my previous listen but that's not saying much.
I now listened to it again at about 25 hours after letting it play over night. I was surprised how it had changed from what I remembered. I swapped the headphones between directly to the PC and through the tube amp. The tube amp was much less muffled than before but still had a mellow and tinny sound compared to the PC directly.
I listened here and there constantly letting with a play list of jazz, piano, orchestra, background chatter, a thunderstorm, sine sweeps, and silence for rest.
At about 50hours this thing has really opened up. I left it with the same comparison song, same cords, computer and headphones during all of this for fair comparison. I now hooked it up to my phone and laptop. It gets loud, stays clear with a mellower sound, and has made my headphones sound amazing. I didn't even know they could play such a range of sound and had been debating selling them before this to get some Sennheiser HD650's. I am no longer dissatisfied but still want the HD650's. I thought these headphones couldn't provide bass but I was wrong.
Now with almost 80hours on it, the sound has improved even more especially with Jazz and Orchestrated music. The 3 Band EQ is amazing as well. I can give it a little more bass or a little more mid or even some treble with ease depending on the song I am listening to or game I playing (yes I now listen to everything through it). I am very glad I did not cheap out $10 and get the one without the EQ. I am thinking about trying different tubes just to see the difference but overall very pleased with my purchase.
I am going to be doing some testing with my earbuds soon on this as I have just wanted a fair even comparison. I would always 0 out the EQ before comparing as I wanted everything to be identical except run time.