Fender Champ Build

[Rciancia]

Hello everyone.

I have a strange problem. I am building a Fender Champ 5F1 and using a proper turret board. The issue is simple yet annoying. When I have the output jack mounted on the chassis, I get a high pitch squeal... when I remove the output jack form the chassis and let it hang ( ungrounded) the amp plays perfectly... no hum, nothing. I have looked for ground loops but really only have two ground points on the chassis.

My output jack is wired as follows :

Black wire from to OT to the Sleeve
Green wire( 8 ohm) from the OT and Green wire from the 22k resistor to the TIP side.


Any idea what this could be ? I do not have a grid stopper resistor installed as I am trying to keep this amp authentic. Any ideas ?

Thanks
Ron

[The Dude]

My first suspect would be that you have the OT primary wired backwards so that you have positive feedback instead of negative. Try reversing the primary leads. Or, if easier, you could reverse the secondary, but you must include the resistor.

[Rciancia]

Thank you , will try that now and report back

[Rciancia]

Thank you so much... that was it... Let me explain why I wired it backwards. On the Fender schematic it had a RED and BLUE wire shown and I ASSUMED that was correct. Big error with a replacement Non-Fender OT. I really appreciate your help very much -

Many thanks
Ron

[The Dude]

No problem. Glad you got it!