Sorry about the delay. I have not heard the Ocean amp. I have the Bravo Audio V2 class A 12AU7 multi-hybrid Headphone Amplifier. It is available for your perusal at www.bravoaudio.com. It drives the HD 700s I have easily and pleasantly. It is clearly not the end all, everything, for the headphone aficionado but the sound quality is impressive, I like it a lot especially for the price paid. I might have even bought it as a MassDrop "drop" for about $60. I happen to have a fairly large tube collection and am having a good time rolling tubes.
I don't know the Ocean amp, and can only say that the build quality is good on the V2 and the sound is better very good. These are made in Shenzen, China, I gather because the parent company is Shenzenaudio, if that matters to you. I am unsure what your concern regarding the gain is, because the amp I have has a volume control..
Thank you for the information you shared. About the gain, while searching I've not seen any amp which has such high fixed gain. Highest I've seen 16dB maybe. That's the reason I concern about. I know close to nothing when it comes to amp so I'm worrying that the high gain could generate noise over headphones or reduce output sound quality.