Hey all! I'm building an AB763 Fender Deluxe Reverb Clone in an electrical engineering class at my University. Im only building one channel (the reverb/ tremolo channel) but I'm having some problems right now getting it to work. As I had a lot of problems getting this to work I basically imitated the normal channel (removing v4 and the whole reverb circuit) and I was able to get this to work. I haven't actually tried it with a speaker but I have a function generator putting a 440hz tone in the input and using an oscilloscope I was monitoring the signal across a 8ohm 5 watt resistor I have connected at the output. It seems to me that without the reverb and v4 the circuit works more or less as expected thus I think the problem has something to do with v4/ reverb in the preamp. Going back to the preamp now. I put the same 440hz tone in at the input, disconnected the preamp from the phase inverter/ power amp, and used an oscilloscope to measure what was happening at the output. Whenever I put in the reverb tube I get all kinds of weird noise in this circuit, but I figured it should still amplify the normal dry signal if I pull the verb tube. So I removed the reverb tube and monitored the output of the preamp- success- I had a perfectly amplified version of the input!! Now I connected this back to the power amp and monitoring the output signal of the entire amp (across my 5w 8ohm resistor) I get pure noise after about 2 o'clock on the volume knob!!! Next I logically thought to check the power amp. I disconnected the pre and power amp, moved my function generator to the input of the phase inverter and magically I get a perfectly amplified signal at the output of the power amp! Also after simplifying the circuit, removing v4 (reverb tube still not in) and taking the signal after the coupling cap (.02) that comes after v2 straight to the phase inverter (essentially the normal channel of the ab763) I was able to get a more or less working amp. So it seems to be not a phase inverter/ power amp issue This leads me to believe that first of all something with v4 is causing an issue? Also something in the reverb circuit is funky too but the amp should work fine (no reverb of course) without the reverb tube in? All the voltages on the tubes are more or less what they should be and I've tried swapping 12ax7's around in the preamp as well as using a 12at7 for v4 in case the tubes were the cause of the problem but that didnt help at all. If anybody has any thoughts they would be much appreciated!