Bassman Ten rebuild

[blues man]

I just finished the build. Its a plexi for the lead channel and a 6g6 bassman for the rythm. I have posted the sch. I have one issue so far. When you dime the vol on the lead channel you can only get the master up to about 3/4. Above that it sounds like it's becoming unstable. Feed back as well as some possible parasitic oscillation. Any tips on taming it down a little. I thought about maybe changing out the 1.5k res on the power tube grids to a higher value like 5.6. would that help?

[VMS]

What happens if you remove V3 tube?

Also, how close are the volume pot wires to the wires of tonestack and master pot?

[blues man]

Thanks for the tip VMS. The master vol wire was routed right by the vol wire and pot. I rerouted the wire and cut off about 4" of wire. I did use shielded wire originally but layout does matter. It definitely got rid of the parasitic. I didn't have time to thoroughly check it out but will tomorrow. I'm trying to rush the build to much and get it done. I just signed up to take the masters electrical exam. The amp building is going on the back burner for the next month.