adamus, I don't know about the sound compared to the SOHA/JISBOS. Only dBel84 has a version of the amp at this moment. I guess one or two of you intrepid builders might have to build one and then compare.
But, there is no surprise that putting a discrete buffer on the SOHA significantly improves the sound. This was my next step before the amp was hijacked.
Ferrari, the other two opamps are indeed for the output stages. But they are isolated from the AC signal paths by 1M resistors. They will not influence the signal. In the picture that dBel84 has posted, the relay is not mounted yet.
MoodySteve, I've got even more designs lined up behind this one.
Many thanks to each of you who has agreed not to buy "unauthorized" boards.