Search brought up WAY too many threads to compile a definite answer. So, I'll keep this short. SVT-CL...power tube distortion is obviously the best, but you have to destroy the room to get it. Changing the V1 a 12au7 (or other lower gain pre-amp tube) to force the 6550s to work harder should get poweramp grind earlier on the volume scale? Or should I change more than just V1? Or am I chasing rainbows? Thanks.