Dr-103 Double-bias-mod chassis pots locations

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traktop
Posts: 26
Joined: Mon Jan 27, 2014 3:27 am

Dr-103 Double-bias-mod chassis pots locations

Post by traktop »

I'm going to make the double bias mod to my hiwatt using a couple of 25k locking shaft pots like this one. http://www.mouser.es/ProductDetail/ETI- ... 52btESU%3d . I was thinking on locating the pots up on the chassis, just using the 2 remaining holes between preamp tubes, and using some sort of bias probe I won't have to deal with all of those potencially killer cables down there...
[img:1024:505]http://www.amparchives.com/Amp%20Archiv ... nside1.jpg[/img]
I see some things on the way: the rolled pair of cables and that big silver cap, but it seems like achievable.
Does anyone performed something like this? Or does anyone have any other useful/"elegant" suggestion/alternative example?
Thanks in advance, Gilberto.
Stevem
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Re: Dr-103 Double-bias-mod chassis pots locations

Post by Stevem »

Have you un bused the amps grounds? The stock wiring is neat as a pin, but does not make for least amount of 120 hz hum you can end up with !
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traktop
Posts: 26
Joined: Mon Jan 27, 2014 3:27 am

Re: Dr-103 Double-bias-mod chassis pots locations

Post by traktop »

Stevem wrote:Have you un bused the amps grounds? The stock wiring is neat as a pin, but does not make for least amount of 120 hz hum you can end up with !
Yeah, that´s what I thought... Maybe attaching a trimmer to a sort of board material piece, drilling holes on the sides for having screws attached to the chassis holes, leaving the trimmer accesible throught the free preamp hole...
Or is just how close would be the cables from the pot the main problem?
The attached files show a dr-504 work where I took the idea from.
Cheers, gilberto.
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