I've had a SFDR with a weber 12F150 that I've always had trouble getting to the sweet spot, mainly because it's too loud. On a whim, I tried plugging into input 2 of the vibrato channel, and voila, I could finally turn the volume up to 6. I finally found the tones I was looking for! By dropping the input signal a bit, I figure this avoids any preamp distortion and just gets the power tube distortion. Is anyone else doing this?