Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: navdave on April 07, 2011, 09:23:32 pm

Title: Vox style cut control
Post by: navdave on April 07, 2011, 09:23:32 pm

This is from the infamous Dime Bag Darrell amp made by Krank.
Wouldn't this put DC on the cut control?

Title: Re: Vox style cut control
Post by: sluckey on April 07, 2011, 09:44:28 pm

Yes. But since no current can flow thru the pot, it's not a problem.

Title: Re: Vox style cut control
Post by: navdave on April 07, 2011, 11:11:19 pm

Thanks Sluckey!
Wonder if there would be any tonal changes if it was placed after the coupling caps like in a Vox amp.

Quote from: sluckey on April 07, 2011, 09:44:28 pm

Yes. But since no current can flow thru the pot, it's not a problem.

Title: Re: Vox style cut control
Post by: HotBluePlates on April 08, 2011, 02:16:19 pm

I'd doubt there would be any difference, since the 2 locations would be functionally the same.

Title: Re: Vox style cut control
Post by: The_Gaz on April 10, 2011, 09:08:09 pm

Yeah, no idea why they put it before the coupling caps - their idea of 'innovation', i suppose. They have also infamously used a variable slope resistor with no cap before the tonestack, placing DC voltage on the control. I'm not sure how that passed safety regulations.

Title: Re: Vox style cut control
Post by: bobmegantz on April 11, 2011, 06:40:08 pm

there is a limit to how much DC you can apply to the resistive element before it will conduct to some other metal part of the pot...

Title: Re: Vox style cut control
Post by: The_Gaz on April 12, 2011, 12:54:10 am

Sure, but the idea is that under some sort of fault the DC would reach the pot's casing. That would be much more unlikely to happen with a blocking cap before the pot, unless of course that managed to fail too. That would be one very very unlucky guitarist.