Jmcgrogan2, I don't know why, but you sound kind of agravated.
I always speak highly of Shunyata products. I think they make very good stuff. I'm not trying to nix the whole product line. I am surprised to see you are taking this rather personally.
I have my system listed and all it takes is a click of a mouse to find out what hydra model I was talking about.
It appears that you'd rather type than click, so I will answer your question. I am using Hydra4. You can see it in my system if you click on it.
I had Hydra2 but that was when I had the McCormack amps and Hydra2 was good. Hydra4 is good with McCormack amps as well. I used it and my friend uses it and the McCormack sounds better with Hydra. Not the case with my Pass Labs amp though. However, I never tried Hydra2 with the Pass, because my the time I bought the Pass amp, I sold my 2 Hydra2 units to get 2 Hydra4.
This may be a screw up on my part because I am not using Hydra4 for the amp and I have 2 outlets in the Hydra4 that are not utilized. I could have easily get by with a Hydra2.
Also, I replied because we are talking about a Pass Labs amp. I have X250.5 and I beleive it is similar in design to the amp in question, the X350.5. Therefore I decided it was appropriate to share my experience.
Your reply is pertaining to BAT using Hydra2 may or may not apply.
That is why the first line of my reply was
It's very simple. It depends on the amp. You have to try it to determine if it works or not. That's all.
