10-27-2015, 06:32 PM
Hey all, throughout my V4 rebuild project I've spent a lot of time looking over the distortion model V4 schematic posted on this site and also the schematic on the AmpegV4 site. The V4 site schem. (actually a VT22 combo version, same electronics) is identical to the diagram on my amp. That said, I've determined the schem. here is the original revision A whereas the other schem. on V4.com is revision D. There are some minor but notable changes in the rev. D version, mostly a few component values and identification changes being the most common. Most of these changes are noted in the Revisions section of the D version, probably worth the read if you have a seventies distortion V4. Now to my question: The rev. A version clearly shows the "N" node coming directly off the treble pot coupled to the input stage of V3 (6CG7) which I assume is the driver for the reverb tank. The rev. D version shows an additional connection from the treble pot to the input of the midrange circuit. This conflict has got me confused, I'm assuming the rev. D has to be correct to feed both the bass and treble of the Baxandall tone circuit to the subsequent midrange section. Am I reading this correctly, are my assumptions correct? Please correct me if I'm up in the night (won't be the first time I've pulled a "Crazy Ivan"), I'm not quite sure how can the rev. A version can work? Thanks in advance...DanB435