Very nice review! You've set the bar high.

Sorry if I missed it, but is your 650 or 6xx modded or stock?

Thanks Allan. both 650 and 6XX are modded. 

Very nice review. Interesting for me as I had only just added the Cayin iDAC & iHA combo to my shortlist. The iFi Pro was already on it as wil be iFi PRO DAC when its released. My 3rd option is the Schiit MJ2 & Gungir Multi. I am looking to listen to them balanced with my Elears. Any thoughts on synergy/pairing?

The 10 khz spike on the Elears won't be further enhanced by this amp and would go well but the upper upper midrange suckout of the Elear won't be helped by this amp. Otherwise I think it would make a great pairing. Better than the cayin for the Elear. The cayin will accentuate that 10KHZ but does have better upper midrange presence. 

Nicely done, interesting HP amp

Great work!  Really appreciate the review!  Thanks

Thanks!