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Hoffman Amps Forum image Author Topic: Tone stack & NFB switch  (Read 1821 times)

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Offline dwinstonwood

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Tone stack & NFB switch
« on: May 07, 2022, 02:44:02 pm »
I'm thinking about a single SPST switch that would cause a pretty big change in my current amp project.

Is an AB763 type tone stack bypass simply a switch that lifts the Mid pot's ground connection?

I would like to combine this with breaking the NFB connection to the speaker terminal, both with the flip of a single On/Off switch.

Any reason this wouldn't work?

Thanks!

Offline sluckey

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Re: Tone stack & NFB switch
« Reply #1 on: May 07, 2022, 03:25:54 pm »
I'm thinking about a single SPST switch that would cause a pretty big change in my current amp project.

Is an AB763 type tone stack bypass simply a switch that lifts the Mid pot's ground connection?

I would like to combine this with breaking the NFB connection to the speaker terminal, both with the flip of a single On/Off switch.

Any reason this wouldn't work?
Yes. You need a DPST switch.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline dwinstonwood

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Re: Tone stack & NFB switch
« Reply #2 on: May 07, 2022, 04:21:30 pm »
Thanks! Of course, that makes sense now that you say it!

It's two separate circuits I'm breaking that can't be shorted together on a SPST.  :BangHead:
« Last Edit: May 07, 2022, 04:25:31 pm by dwinstonwood »

Offline dwinstonwood

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Re: Tone stack & NFB switch
« Reply #3 on: May 08, 2022, 10:38:57 am »
I don't want to run speaker jack wires back and forth across the chassis to this front-mounted switch. So, I'll try this setup and see what I think. It's easy to disconnect if it turns out to be a bad idea. And, I can always add a second switch on the back of the chassis next to the speaker jack to disconnect the NFB.

"ON" = tone stack and bright cap
"OFF" = tone stack bypassed and no bright cap

 


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