I'm in love with my first headphones, the 407 with the SRM-006tS and am so curious about the 009. I don't listen real loud, 85db peaks. Will this amp drive the 009 well?
I don't have any direct experience with that Stax amp so can't comment, but you might want to try asking this in the Stax thread:
Lots more users there with quite a bit of combined experience with just about every combo out there.