Got my AD20 today built up a cable to supply power offa a single 9.6v rc battery. Sounded VERY noisy. Used a seperate battery and the noise floor dropped. (the preamp in this is VERY quiet compared to the SP-PREAMP)
So, I guess I will stick to a regular 9v for the plug power and just use the rc pack for the ad20...
Least I didn't let the smoke out first day I had it!