I'll try the 8610s again and see. If they're fine (in terms of distortion) would that mean the OPA627s are bad and should be replaced? From what I've read they should be a drop-in replacement for the 8610s, yes? BTW, I put the OPA627s in all three slots (including the ground circuit). I...

The amp was built by SubSonic, and this is what he had to say about the PS: "In regards to the power supply, it's a variant of Tangent's STEPS which is basically derived right from Linear's datasheet. I drew up the artwork and etched and drilled the pcb myself. Also I use 8000uF of output...

I've got a PPA that I bought from a member here some time ago and I've been using it with some HD600 phones. Actually, not using it as much as I'd like for a variety of reasons, one of which was that it was a bit too forward/aggressive for my taste. After reading a bit here I learned that the...