BPT 3.5, Audience aR12, or Equitech 1.5Q?

The improvements are not small. Bigger than a component upgrade.

I have an Audience aR6 and like it a lot. If you decide on an Audience, be aware that at some point Audience changed the grounding system on both the aR6 and the aR12’s. The Audience website mentions an upgrade option, and identifies how you can tell if a specific unit has the newer grounding system.

I have owned both the Hydra 8, BPT 3.5 Sig, and the Equi=Tech 1.5Q over the years. My amps lost dynamics with the 1.5Q and sounded better going to the wall. The Hydra 8 did not have this problem, and sounded very good. The BPT 3.5 Sig. sounded even better than the Hydra 8, with improved dynamics, detail and 3-D soundstage.
You will find that the stock power cords for each will be a VERY limiting factor. Upgraded cords from these units to the wall make a big difference.

Bigshutterbug, that's a good point. The Audience units come with a powerChord e, which is my cord of choice and used elsewhere in my system. It would be great to hear from somebody who has used an aR6 or aR12 and one of the balanced power units.

Raks, I'm not seeing the info on the newer grounding system for the regular models, but I have read elsewhere of the changes with the T and TS models. Is that what you were referring to?

Bigshutterbug,
I`ll defer to you since you have experience with all 3 units. I just assumed the Equitech would be quite similar to my BPT 3.5 Plus(share balanced AC concept) I guess I was wrong.You are right, amplifiers are better with the BPT than when I had them plugged in my wall(dedicated line with 20 amp service).This is true for my 8 watt SET 300b amp as well as my previous 100 watt push-pull tube amps.