Smoke

[ratgon]

Hi all. Well I'm back with a new issue. Still working on figuring out the solution the the utterly silent amps I've been building lately. Beautiful pieces of art but no sound. It's gotta be in how I'm wiring the input and or output jacks. By the way thank you ALL very much for all the help with that even got a bunch of private messages. It must be frustrating to know the answer to someone's question but dealing with them not picking up on it so again, thanks.

Anyway, while I was waiting for a couple of components to arrive to try again with the silent amps I decided to finish my Hoffman 5f1 project I started a couple of weeks ago ( that's another issue, too many projects going with my attention to detail too spread out). So I finished it and did my dim bulb test. Checked voltages. Everything seemed fine until I started to see some wisps of smoke. Utterly silent smoke of course. Anyway, given my layout it was either the one pot or R 14 which, on the Hoffman layout has a small little note saying use a choke if building an 5f1. I suppose that's instead of using the same board and making a Princeton?

Anyway, my question is if I'm building a straight up Champ. 5f1...do I HAVE to use a choke in that position (first resistor after first power filter cap). And also, if in fact that is the case, why wouldn't the Princeton need it as well considering it's simply the addition of a tone circuit

Thank you all for your patience in advance.

Oh, and I actually have built some amps that actually work without any smoke even!

[eleventeen]

Silent amps! I like it! 

[ratgon]

Man, I'm tellin' ya. I got 'em down. Purely silent amps!

[sluckey]

Anyway, my question is if I'm building a straight up Champ. 5f1...do I HAVE to use a choke in that position (first resistor after first power filter cap). And also, if in fact that is the case, why wouldn't the Princeton need it as well considering it's simply the addition of a tone circuit

The 5F1 does not use a choke.

The original 5F1 and 5F2-A do not use a choke. The 5E1, 5E2, and 5F2 use a choke. Look at the schematics for all 5 of these similar amps. Also notice, that the amps that use a choke also move the OT lead to pick up B+ AFTER the choke, not before the choke as seen on the Hoffman drawings. This reduces hum.

[ratgon]

Thanks. Well I'm just purely going by Doug's 5f1 layout and he has that note right next to R14. So anyway, I changed it out for a choke and smokes all gone. And that resistor def had signs of scorching.

[ratgon]

I answered too soon. Thanks for the note about the OT placement and chokes. I appreciate the tip.