Tweedle Dee NFB

[Oddvar R]

Hi. I just finished my Tweedle Dee build. I have use an old Epiphone Valve jr chassis I had and I am using the output jacks from that. I am wondering how to connect the NFB to that- When I connect it to the 8 ohm I only get squills. Any suggestions?

[pompeiisneaks]

If you're getting squeals with NFB that means your output transformer leads are IN phase with it, causing PFB instead. Swap the OT leads or the PI outputs to the tubes so that you reverse the polarity and the squeal should go away.

~Phil

[Oddvar R]

Hi and thanks again, but since there is only one tube, I don't see how?

[pompeiisneaks]

The phase of the OT can still be out even in single ended. The first time I had this problem was with a champ build that howled to the moon... with it's single 6V6.

~Phil

[ChopSauce]

Hi and thanks again, but since there is only one tube, I don't see how?

Like Phil wrote, it's just a matter of polarity of the current (in the transformer).

If you change the polarity, then the action reverses - like substracting something negative finally adds, roughly.

Whether the current in the transformer is caused by one or a multitude of tube does not change this.

(just in case you didn't caught it already)

[Oddvar R]

It worked, thanks guys...