Alright I just bought a JTM45 with a transistor rectifier. It sounds super good and I love it. BUT:
When I plug into high sensitivity Channel 2, the High Treble AND the Normal volume both affect the loudness... but the high treble doesn't affect it as much as when you jump it... why do both volumes affect one channel???? the seller told me he would pay for any repairs and what not which is really nice so i know he ain't givin me the slip...
its not really a transistor rectifier, its just a diode rectifier.

I'm not sure about the problem though. Technically the high treble channel shouldn't really be affecting the normal channel at all unless you're bridging the channels. I can't say for sure though, I NEVER use the normal channel on my JTM45, I always use the high treble, high input and bridge.