Hmmm.... so my EHP-O2 amp arrived yesterday and I had a play around it. I initially thought that the 598s being only 50ohms would be easy to drive. But without turning on the gain settings, I had to turn the volume knob to to about 2 oclock to match unamped volume and 3-4 oclock to have a nice amped sound. I was wondering if this was normal. I think the default gain settings for the EHP model are x1 and x5.
Any 598 users with O2 amp can shed some light?