Delay self-oscillation problem with Dumbleator

[Luthierwnc]

I took the head downstairs tonight to replace the return (MV) pot with a push/pull version that will switch the Dumbleator in and out. It's on the back of the amp -- so not the best placement -- but if it works I'll consider more extensive surgery. I did have to order the pot. As it stands right the amp sound great but the loop is not usable for effects. It's just too hot. Perhaps a parallel blender would do it. I'd like to hear the amp without the loop at all first and make that call.

Thanks again to everyone who chipped in. If the results are interesting, I'll get back to you. sh

[dbharris]

Thanks dbharris. I forget the voltage divider but think it was 100k to ground after a 270k. I'm coming to the conclusion that I like the D-Lator better as an effect than as an active loop. The FET I could live without so I may convert that switch to a p/p pot and steal the relay to make the loop switchable. That and I don't play dirty enough to really hurt the minimal delay and reverb at the end of the chain. I'll keep fiddling because that's my hobby.

A good solution might be staring me in the face. My little home amplifier has an effects system I borrowed from leonc (a very good So. Cal amp builder in his own right). https://www.youtube.com/watch?v=NO2fqf8jk0Q

He rigged a low-tech version of Carlton's set-up but using an H&K redbox between the speaker and head rather than a microphone. I use a Radial Cablink which has a handy pad to dial in the right output to a Boss SE-50 FX processor. That splits into stereo into a little Stewart PA-50b amplifier and then into two closed-back 1x10s on either side of the wall. Works great. It never leaves the house, though. The attached drawing is a few years old and I never hooked-up the Midi Xchange. Other than that it's as shown.

Cheers, sh

You may want to double check that voltage divider. If I am understanding correctly, you are dumping almost 2/3 of your signal to ground. You should be able to pass a lot more signal and then adjust overall volume with the output of the loop.

-Dan

[Luthierwnc]

Thanks Dan. I'm going to drop a 500k trimmer in there and season to taste. sh

[Luthierwnc]

Replacing the 270k/100k voltage divider with a 500k trimmer for fine tuning.

Nutha question; I'm not married to that dry/wet pot value. It's 25k now. bcook thought I might try a 250k in there when I was chasing the gremlin. Any other ideas on that or a different circuit? Thanks, sh