Lots of gear changes coming in my different setups. I wanted to give a few impressions of the amp before too many variables changed. The amp out of the box sounded strident. I let it cook overnight and came back the next morning. Better. Something still strange. I think this amp is just really revealing of upstream source. I took my Bimby and threw in a Wyrd. There. Much better. One thing I found again is my HD600 and HD650 really (to me) sound better single ended. I had that experience with several other amps. I think perhaps the brute force this amp unleashes may push the already lush mids and upper bass too forward on some recordings. Just my two cents. Both are still good. That said, I'm very impressed with this amp. I'll be bringing my Yggy back into the office and out of my speaker system to see how much this amp scales with improved sources. So far, I've tried all my cans in my list. Each one of them sounded fantastic. So, right now with single ended in and out, I've got plenty of juice to power all my SE cans.
I started a little lower than you, but was running Wyrd into my Mimby. Definitely try the Yggy. It's where I ended. And I agree, the revealing nature of this amplifier is such that better input provides better output. And oh...the output from the Yggy is oh so pleasurable through the Jodie.