Crazy 5f1

[longo3]

You are the amp man Bruce.

I reversed the ot red and blue and now I can ground the speaker jack to chassis .

I think it has a more mellow (not breaking glass) at full volume

[Tom Phillips]

... now I can ground the speaker jack to chassis. I think it has a more mellow (not breaking glass) at full volume

When you had the speaker output floating there was no ground reference for the feedback circuit. Therefore the feedback circuit was essentially switched off. When you corrected the phasing of the output transformer and then were able to ground one side of the speaker output to the chassis you were also making the feedback loop operative for the first time in this build. I'd say that's why the amp now sounds more mellow.

[longo3]

Yeah I just went by the red and blue wires. so much for a drop in replacement. in the 5c1 circuit the red and blue were fine, it didnt make a difference I had the jack grounded.