Tweet
Hi all,
I am trying to root out an issue that I've never seen before, and it's driving me crazy. Could use some help!
I am building a point to point Fender 5D5 clone on the chassis of an old Knight PA amp. My issue is bizarre: With either one and only one of the 6L6 output tubes seated, I'm getting normal operation. Everything sound's fine, quiet, and good, as long as I'm only using a single tube.
However when I install both output tubes, crazy motorboating starts as soon as I hit power and the tubes warm up.
I have tried to eliminate all the variables I could think of:
1. The power tubes I"m using are all good. I have swapped in or out six-seven tubes, in both sockets. No difference in the issue.
2. I was reusing the original octal sockets for this build. I have since removed both of them and installed quality new sockets in their place.
3. I have checked, re-checked and checked again, five or six times, the wiring throughout the entire amp. Everything is correct.
I'm thinking at this point that it's got to be some kind of lead dress issue. Can anyone take a look at the photo and tell me if you see any red flags with respect to lead dress? Or offer any suggestions? I'm all ears!
http://www.thevintagesound.com/ffg/s..._5d5_schem.gif
I am trying to root out an issue that I've never seen before, and it's driving me crazy. Could use some help!
I am building a point to point Fender 5D5 clone on the chassis of an old Knight PA amp. My issue is bizarre: With either one and only one of the 6L6 output tubes seated, I'm getting normal operation. Everything sound's fine, quiet, and good, as long as I'm only using a single tube.
However when I install both output tubes, crazy motorboating starts as soon as I hit power and the tubes warm up.
I have tried to eliminate all the variables I could think of:
1. The power tubes I"m using are all good. I have swapped in or out six-seven tubes, in both sockets. No difference in the issue.
2. I was reusing the original octal sockets for this build. I have since removed both of them and installed quality new sockets in their place.
3. I have checked, re-checked and checked again, five or six times, the wiring throughout the entire amp. Everything is correct.
I'm thinking at this point that it's got to be some kind of lead dress issue. Can anyone take a look at the photo and tell me if you see any red flags with respect to lead dress? Or offer any suggestions? I'm all ears!
http://www.thevintagesound.com/ffg/s..._5d5_schem.gif
Comment