Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: navdave on April 30, 2012, 04:28:17 pm

Title: CBS Super Twin master volume
Post by: navdave on April 30, 2012, 04:28:17 pm

I love the way this amp sounds with pedals and I plan on cloning it minus the tremolo/reverb channel. I want to keep the master volume control but not the funky dark switch that CBS used. I drew up this schematic is this how I would do it minus the tremolo and dark switch?

Title: Re: CBS Super Twin master volume
Post by: PRR on April 30, 2012, 11:17:43 pm

.

Title: Re: CBS Super Twin master volume
Post by: navdave on May 01, 2012, 01:47:41 pm

Thank you very much for pointing that out PRR got it!!

Title: Re: CBS Super Twin master volume
Post by: PRR on May 01, 2012, 04:41:41 pm

Your way would reduce volume, of course, the usual way (tap-down signal with a pot).

But Fender chose to do it by increasing negative feedback and reducing output stage gain. That makes the output stage more tame when MV is low.

I'm not sure of the merit either way. But you want to "clone" this, you probably want to start the way Fender had it.

Title: Re: CBS Super Twin master volume
Post by: Willabe on May 01, 2012, 04:55:10 pm

Quote from: PRR on May 01, 2012, 04:41:41 pm

But Fender chose to do it by increasing negative feedback and reducing output stage gain. That makes the output stage more tame when MV is low.

Ohhh, that's what it does. Thanks for explaining it PRR.


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