HORRIBLE 5E3 Clone Noise

[SteveInMN]

After I hit the strings, you can hear the amp  make a follow up noise, sort of like a slap back echo. I’ve poked and prodded all the resistors, capacitors, potentiometers, tubes/tube sockets, wire connections,  etc., no reproduction of the noise. Changed the preamp tubes, no joy. Could power tubes or the rectifier tube cause this? Any ideas appreciated!

I am so desperate I figured out how to post on the Youtubes. Crikey! :

[bnwitt]

Have you tried tapping on the tubes one at a time with a pencil or chopstick lightly?  If nothing there, tapping on components inside the amp with a chopstick?  Which layout did you use to build the amplifier.

[SteveInMN]

 Yes!  I’ve poked and prodded all the resistors, capacitors, potentiometers, tubes/tube sockets, wire connections,  etc., no reproduction of the noise. Changed the preamp tubes, no joy.

The layout is standard 5E3.

[tubeswell]

Some kind of ultra-sonic modulation possibly resulting from sub-nominal layout or insufficient RF suppression or unwanted EMF coupling would be my guess with seeing any pictures. How good is your lead dress and layout?

[Jennings]

Maybe check the speaker, and anything loose in/on/round the cab...sometimes you're sure it's the amp, but it's actually the speaker/cab.  Maybe also check the bias setup for the power tube too.

[bbmade]

Yes!  I’ve poked and prodded all the resistors, capacitors, potentiometers, tubes/tube sockets, wire connections,  etc., no reproduction of the noise. Changed the preamp tubes, no joy.

The layout is standard 5E3.

I went around in circles on my 5E3 build and was having some horrible distortion issues.  It turned out to be bias problems because I missed a short jumper wire and had +5 volts in the grids of my power tubes.  Perhaps measure the voltages of each tube pin to see if they are within an expected range? 

This forum helped me figure out my issue after many hours of bewilderment.

[SteveInMN]

Thanks all for the kind input!  Without having to go to Slidell, or West Memphis, I have found my joy.

Because the noise happened AFTER the guitar signal input stopped, I figured energy must be being stored somewhere, then released. Which made me think capacitor.

Most all the caps are new and high-quality. The only 'suspect' capacitor was an ancient but oh-so-cool-looking domino I used for the tone capacitor. I swept the tone dial, and the noise was HORRIFIC on 1, and all but gone on 12.

I replaced the tone cap with another ancient but oh-so-cool-looking domino, and voila, noise gone.
For now (we all know how this goes!).

BTW, I use 0.003uF instead of the stock 0.0047uF for the tone cap. The reduced value puts the center of the usable tone range at 6, instead of the usual 9 -- FWIW.

[bnwitt]

Congrats