John, have you tested the amp using different headphones?
Dimitri, did you get your Plainviews from
www.thomasdistributing.com? it says the are 9.6 volts, which it means that they are even better than regular alkalines (9 volts)??
See it's strange if you get AA nimh you can only get 1.2 volts instead of 1.5 volts (regular alkalines).........
I hope the plainviews will last as long as regular alkaline batteries. What I plan to do is to charge them every week...it would be more than enough. Keep in mind that they (NIMH) lose about 3% of the charge everyday even if they are not in use.