I've asked Neco in the past about creating a balanced amp. There are a couple of problems, however. First and foremost, this is essentially a hobby for him. He has a "real" job during the day that keeps him pretty busy.
As for what you've shown above, as a non-tech guy with little understanding of how stuff works, I notice a few potential issues based on my (mis)interpretation of things I've read elsewhere:
- The inputs on the amps would still be unbalanced. Maybe not a big deal if all you are going for is power, but your inputs would be signal and ground, instead of positive and negative.
- Again, I may be wrong, but I'm not sure that using two amps would actually be more powerful than one when used that way. Consider speaker amps. I don't think there is a difference in power between driving two speakers with one amp, vs. driving two speakers, each with a separate amp, unless the amps are "bridged". Otherwise I think you are just using half of the amps' power for each speaker, so you might as well just use one amp and drive both speakers. So you would have to find out whether Neco can somehow "bridge" one of his standard amps. I have no idea what that entails...or if anything I just wrote is actually true.
- You would have to control the volume for the left and right channels separately. Not a huge deal, but annoying. Maybe you could connect the volume pots using a silicone band so that they would turn simultaneously?
- The cable shown above has two 1/8" plugs, but they both appear to be TRS/stereo. I think it would probably make more sense to work with two mono plugs (although it probably doesn't matter if you just don't connect the 3rd conductor to anything in the XLR plug).
Best,
Adam