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.