I faced a new problem on my HD500. I prepare a preset with two amps (lets put it 1A). And other preset by using two amps too (put it 1B) and a other preset by using one amp (1C)
When I start using 1A it sounds OK. Then I move to 1B , I sounds different, like I reduced the level of one amp. Left channel sounds like reduced . Then I move to 1C and turn back to 1B it sounds OK. Again 1A and than 1B it sounds reduced (only one, left channel)
I hope I explained my problem clearly (sorry for my English)
I always use HD Edit to create and tweak presets.