I recently replaced the new production JJ 5Y3 rectifier tube in my Tweed Champ with a NOS 5Y3. Did this for reliability reasons. I may be crazy, but I think the amp sounds a little different - like it lost a little clarity. I mostly play cleanish/slight OD at around 5 to 6 vol with single coils. My question is whether a different rectifier tube can influence tone......or is this all in my head? Thanks!