Your ears aren't flat...literally or sonically. And oh yeah, they're not digital, either. Sound isn't flat, and the world isn't flat. I could go on and on about why we like round things better than flat things, but this is a review of a tube-based headphone preamp--specifically, one of the least expensive entrees you will find that still somehow manages to give you a tone and an immersive experience different from any solid-state alternative.
To be sure, there are plenty of excellent solid-state headphone preamps available, even some at true entry-level price points--but the role they take is to provide a clean, unadulterated level matched to the wide requirements of an array of headphones and get out of the way sonically. Leaving the sonic signature to the headphone itself is a valid premise; however, with tubes, we are going after a blend of the best, matching the characteristics of the headphone to the genre or even the specific piece of music at hand. This approach explains why many, myself included, have different headphones and different signal paths for different listening sessions. There are many excellent articles, both emotional and technical, dealing with the differences between solid-state and tube amplifiers, so I will leave that discussion to others and concentrate on this particular tube headphone preamp: the Bravo V3.
Bravo Audio makes essentially six products: four tube-based headphone preamps (the V1 Deluxe at $75, V2 at $70, V3 at $85, and Ocean at $120); one solid-state HD preamp (the S1 at $70); and a guitar pedal (the Soap at $95). Aside from the solid-state S1, these are all low-cost, no-frills tube devices, which allow Bravo's customers to get a little taste of what "that tube sound" is all about.
Oftentimes, a reviewer's philosophy is to start at a much higher price point to offer insight into the best of the best before you plunk down your money. This can certainly be a valuable approach, so why am I reviewing an $85 headphone preamp instead? Because Bravo is doing something special here. McDonald's may not give you a glimpse of what a three-star Michelin dining experience can be like, but Bravo is giving you a glimpse of what a McIntosh, Cary Audio, or Glow Audio tube headphone preamp experience can be like...at a fraction of the cost. They are, in fact, opening the door just a little and giving us a peak inside the rarefied and often pricey "tube sound" experience.
How do they do that? By keeping it simple. The Bravo V3 is not a no-compromise, cost-no-object work of art attempting sonic perfection. However, there are some pretty impressive specs on paper that support the quality I heard. The V3 has pure Class A topography. Input sensitivity is listed as 100 mV; input impedance is at 100 ohms; output impedance is 20 to 600 ohms, providing 30 dB of gain with a frequency response of 10 Hz to 60 kHz, +/-0.25 dB. Dynamic range is 84.6 dBA (300 ohms) and 89.9 dBA (33 ohms). THD is 0.016 percent at 300 ohms and 0.45 percent at 33 ohms. Inputs include RCA (L/R) and an eighth-inch (3.5mm) jack, and the output is a quarter-inch (6.3mm) jack.
The Bravo V3 has a Plexiglas top and bottom and is open on the sides--which, in addition to saving money, allows for cooling without a fan. The V3 employs a passive three-band graphic EQ providing simple yet useful bass, mid, and treble adjustments. Both the V1 Deluxe and the V3 ship with an EH 6922 tube, while the Ocean and V2 are supplied with the Shugguang 12AU7. To my ears, the EH 6922 delivers punchier bass; with the help of the V3's EQ, I was able to open up the mids to where I was hearing everything I was hoping to hear: great detail, smooth transitions across the frequency spectrum, and that tube warmth I sought.
My setup from source to ear was as follows: hi-res FLAC files played back via the VLC player on my 2015 Apple MacBook Pro, coming out of the headphone output into the Bravo V3, then into my Sennheiser HD 580 Precision headphones. The 580s have a little less bass and were designed to be more neutral than the smiley-face accentuated lows and highs of many other headphones. The Sennheiser 600s and 650s, for example, are warmer and have a more pronounced high-frequency response. All three headphones from Sennheiser have great detail and clarity with wonderful soundstage presentation.
The Bravo V3 proved to be a perfect match to my HD 580s. The passive EQ allows me to make adjustments when switching between genres. For dense rock, jazz, and other "busy" tracks, I set all three bands to their lowest positions. For airy, spacious tracks, my preference landed at 6, 4.5, and 4 (there are arbitrary lines scaling the fader travel from 1 to 7, with 1 being the lowest position). The volume potentiometer was smooth and generated no audible noise. My 300-ohm HD 580s were nicely driven at about 30 percent when the volume on my MacBook Pro was at 75 percent. I've read that, in the case of my Apple MBP, the computer volume is subtractive, meaning there is no boost at full volume, only attenuation at anything below full volume. Since I hear no distortion when using VLC, I am inclined to believe this, but going with 100 percent output from my MBP somewhat seemed to overload the V3's input--so I attenuated down to 75 percent, which yielded solid, distortion-free output all the way through to my headphones. I even experimented with setting the MBP's output quite a bit lower just to see what turning up the V3's output does in terms of clarity and tonality. The results were pretty much the same. Suffice to say, the V3 can drive the Sennheiser 300-ohm headphones easily with plenty of volume and distortion-free results.
For comparison and reference purposes, I also used a pair of Sennheiser HD 414 Reissues (love the yellow pads), the stock earbuds from Apple that came with my iPhone 6, and Audio-Technica's QuietPoint active noise-cancelling in-ear monitors. They all worked, but to get the benefits of what any tube preamp can deliver, a premium set of headphones is required.
I also highly recommend that you invest in hi-res audio sources; my preference is for FLAC files, and my listening sessions included some wonderful recordings: "Chan Chan" from Buena Vista Social Club; "Come Together" from Abbey Road by The Beatles; "Hells Bells" from Back in Black by AC/DC; "Domine Deus" (Rossini) from Sacred Arias by Andrea Bocelli; and "Call It Stormy Monday" from In Session Live by Albert King and Stevie Ray Vaughn.
"Come Together" challenged the V3's ability to resolve the mids, missing a level of detail and air that I've heard with other preamps, both tube and solid state. The Bravo V3 handled everything else I threw at it extremely well and provided hours of enjoyment and immersion way beyond what its diminutive price point would suggest. Did I keep listening to other tracks in my extended listening session? Yeah, I did, with a big smile on my face.
• I heard no noticeable hum or any other inherent noise with the V3. I have heard others mention that the V3's lack of shielding makes it susceptible to picking up interference from other nearby sources, but they also indicate that the noise goes away by moving or re-orienting their setup. I put my iPhone right next to the V3 and did not have any problem.
• The V3 has plenty of gain. It even drives 600-ohm headphones without any trouble.
• The warmth, clarity and detail one looks for in a tube device were all here, and all but the densest mixes resolved nicely, retaining a depth and soundfield integrity that belied the price of the V3. I have yet to find anything better anywhere near this price point.
• The V3 does not have a line output, which would have made it easier to use this as a tube preamp feeding a loudspeaker amplifier (tube or otherwise). One can always use a quarter-inch stereo-to-dual-mono RCA adapter cable to go from the headphone output to the amplifier input, but care must be taken to adjust the preamp volume for proper gain structure.
• Some dense tracks proved a little too much for the V3 to cleanly separate the instruments when certain frequencies had a lot going on.
• The Plexiglas minimalistic housing is not likely to impress most, but are we listening or looking? At higher price points, I would say I want it all, but at this price I am more than okay with a simple aesthetic.
Comparison and Competition
Firstly, remember we are in the sub-$100 price point with the Bravo V3. There aren't many that even try to play in this sandbox. I've included one here that I myself have not heard. By extending the price range up a bit to $300, a few more competitors that bear mentioning.
The Little Dot I + ($115) uses two 6JI tubes and offers similar specs. You get an aluminum housing, internal DC converter, and beefier transformers for the $30 difference. Remember the Bravo V3 is only $85, so that $30 represents a 35 percent premium. Even with the aluminum housing, there are reports of shielding issues.
The Little Dot MKII ($184.99) includes four tubes: two 6JI driver tubes and two 6N6 power tubes. This is a single-ended, push-pull output, transformer-less design yielding a 20 Hz to 50 kHz frequency response, and it can drive 600-ohm headphones. For $100 more than the Bravo V3, you get RCA preamp outputs, an internal power supply, and aluminum housing. Are four tubes better than one? I could write an entire article on how tubes can be wired differently to achieve vastly different performance, but it comes down to sound at the end of the day. If $185 is entry-level for you, this would be a great start to getting into that tube sound when completing your signal path.
The Dark Voice 336SE ($320) is more than three times the price of the V3, but this tube headphone preamp uses one 6N8P and one 6N5P tube. It has an aluminum case and outsized transformers. Most owners immediately replace the stock tubes and are ultimately happy; but, if you have to do that up front, maybe there are better options at (or below) $320?
After reading all of the above, your question might be: What does a thousand-dollar-plus headphone preamp give you that this $85 Bravo V3 doesn't? For the extra zeros to the left of the decimal, you can get an even deeper soundstage, enabling you to place the instruments and vocals within their own space. The air between frequencies imbues a "presence" to the overall experience of immersive listening, especially in the higher register. Greater dynamic range translates to more impact when passages pull back before a crescendo. Transients are faster, sharper, and contribute to the feel, the pacing, and the groove by bringing into focus the precise timing of the pluck of a string, the tip of the trumpets' trill, or the rasp of an emotive vocal.
But not everyone has that kind of budget. The Bravo V3 is a perfect choice if you already own a top-level headphone and you crave that tube sound without having to spend a fortune. Even if you have plenty of money but you're not sure if the tube experience is something you want, the V3 can be a rewarding and inexpensive way to find out.