u/TheRealDonBalls

Help! My Mojotone 5E8-A amp is squealing.

I built this 5E8-A from the Mojotone amp kit and upon firing it up for the first time it’s got this terrible high pitch squeak. It changes some when I turn the treble control, but other eq/volume pots do nothing. I’m also not getting any sound from the input jacks when I plug something in. It’s just squeals.

I’ve checked continuity everywhere on the board near as I can tell. Also checked continuity on the tubes, though I don’t have a tube tester.

Not really sure how to troubleshoot from here. Any help would be greatly appreciated. Thanks!

EDIT: Thanks for the help everyone! Got it working great. It was indeed the output transformer that was wired backwards. I had wired it correctly according to the instructions so either the instructions had the colors wrong or the transformer was made incorrectly.

u/TheRealDonBalls — 2 days ago