Bravo Audio has released the tube headphone amplifiers (V1, V2, V3 & Ocean) for quite a while. And I have line up all 4 models for a comparison.
Bravo V2 & Ocean
These 2 little amps, V2 and Ocean are using Shuguang 12AX7 tube. And I’ve talked to Bravo Audio, they are using very similar PCB except there’s RCA output and AUX input in Ocean. So, Ocean can work as a preamp as well. And Ocean come with a stylish casing (except the blue color I dun like it personally). The casing on Ocean make by aluminum and it helps to lower the temperature in the amp. There’s a round shaft going on top of the tube which can prevent to touch the hot tube accidentally.
Besides those, they are exactly the same in term of hardware and sound tones.
Bravo V1 and V3
For these 2 amps, they are using Harmonix EH6922 tubes from Russia. It could easily explain why V1 is more expensive than V2.
Again, V1 & V3 are using similar PCB except V3 have 3 equalizer switches.
These switches are not common in a little headphone amp for this price range.
I’ve test these amps with different songs base on 2pairs of earphones. The 12AX7 tubes (V2 & Ocean) perform well in heavy bass music and most pop songs; the EH6922 (V1 & V3) give a warm and sweet sounds for vocal, perform well on mids and highs.
To conclude, it really depends on the type of music to listen to choose between the models. And it is always a personal favour for the sounds that vacuum tubes provided. However, I could said that this is a good entry for audiophiles who want to listen to tube sound at a very reasonable price and quality provide.