Wow wood, you are runing at 7v eh? You did not notice any negative effects of this? Like a thinner sound? That is interesting. I thought they where supposed to run at 7.5 volts min. I'd say run them as low a voltage as they sound good at, it can only help heat/stress. chips run cooler, psu runs cooler etc.
off topic: Does anyone have experience with different OPAMPS? Im thinking of trying a pair of AD797BRZ on a browndog adapter.
OPAMPS, They will sound different but IMO never that great. Lots of feedback. See Operational Amplifiers or Op-amps Tutorial
Feedback plus transistors, well it is just not my cup of tea. See page one where it states that the ideal opamp has infinite gain. Gotta have feedback.