Hey guys... I tried searching first but couldn't find my answer. I know someone here knows for sure. The amp is from 1977. I want to try some 12AX7s I have in this amp and need to know which of the three should I try if I want to effect the distortion the most. More gain. I dont even know which is V1 , V2 or V3. Thank you for any help. Cheers guys.