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Hoffman Amps Forum image Author Topic: bias tap question  (Read 2430 times)

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Offline firemedic

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bias tap question
« on: November 23, 2011, 11:39:09 am »
I got my first non-CT power tranny from Weber, the one for a TR. It has a 50vac bias tap but with no ground reference CT, where do the 2 bias leads go?

Specifically, I figure the blue lead must feed the bias supply like I'm used to, but what about the other lead?

Offline ernie_jr

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Re: bias tap question
« Reply #1 on: November 23, 2011, 11:45:24 am »
The red/yellow is the CT for the high voltage and the bias, blue red is the bias tap. Wiring diagram is on Weber's
website.
Ernie

Offline sluckey

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Re: bias tap question
« Reply #2 on: November 23, 2011, 12:24:55 pm »
Sounds like you have a PT with a totally separate bias winding (like the Reissue Twin Reverb). If so, one bias lead goes to ground and the other goes to the bias circuit. Refer to page 8 of this schematic for an example...

http://www.el34world.com/charts/Schematics/files/fender/65_twin_reverb_%20manual.pdf

Or see this pic...


« Last Edit: November 23, 2011, 12:33:41 pm by sluckey »
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline firemedic

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Re: bias tap question
« Reply #3 on: November 23, 2011, 05:34:28 pm »
Thanks!

stratele52

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Re: bias tap question
« Reply #4 on: November 23, 2011, 05:59:06 pm »
Sounds like you have a PT with a totally separate bias winding (like the Reissue Twin Reverb). If so, one bias lead goes to ground and the other goes to the bias circuit. Refer to page 8 of this schematic for an example...

http://www.el34world.com/charts/Schematics/files/fender/65_twin_reverb_%20manual.pdf

Or see this pic...





+1 slukey

 


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