How to install a bias pot in a Rectifier

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nakedzen
Bottle Rocket
Posts: 17
Joined: Fri Dec 13, 2013 7:31 am

Re: How to install a bias pot in a Rectifier

Post by nakedzen » Mon Feb 17, 2014 4:40 am

Gnarkill3k6 wrote:When you're able to change something that was fixed... that means it's variable/adjustable and not fixed anymore, right?
Fixed bias = it stays where it's set. The other variety are the cathode bias amps that adjust the bias automatically.

http://www.thetubestore.com/Resources/M ... Bias-Types

mat.corona
Bottle Rocket
Posts: 3
Joined: Thu Apr 10, 2014 3:26 am

Re: How to install a bias pot in a Rectifier

Post by mat.corona » Mon Aug 25, 2014 12:36 pm

Hi,
Has anyone found the Mouser part number of the Bourns pot (pannel mount)?
I'm writing from Italy, I wish to order it in europe if it's possible.
Anyone can help me?
Any suggestion of other brands good quality pots?
Best regards.
Matteo

mat.corona
Bottle Rocket
Posts: 3
Joined: Thu Apr 10, 2014 3:26 am

Re: How to install a bias pot in a Rectifier

Post by mat.corona » Mon Aug 25, 2014 4:32 pm

For exemple. Is this one a good choice?
http://www.tubesandmore.com/products/R-VPEC-50KL
Thanx
Matteo

afu
Mark IV
Posts: 662
Joined: Thu Aug 15, 2013 12:20 am
Location: Tucson, AZ
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Re: How to install a bias pot in a Rectifier

Post by afu » Wed Jun 03, 2015 1:34 pm

mat.corona wrote:For exemple. Is this one a good choice?
http://www.tubesandmore.com/products/R-VPEC-50KL
Thanx
Matteo
Yes. The power dissipated is about 144 milliwatts. So a 2W pot will be fine and that one looks like a quality part.
2007 3 Channel Dual Recto w/loop mod

My Humble Music Tech Blog:
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RussB
Mark III
Posts: 377
Joined: Sun Jan 30, 2005 6:53 pm
Location: Connecticut

Re: How to install a bias pot in a Rectifier

Post by RussB » Sat Mar 03, 2018 11:20 am

I notice that photophuckit hijacked my pictures, so I'll repost...


I installed a bias pot in my Single Recto today. I used a 50k pot with a 1/2 watt 47k resistor in parallel with the two outside legs. Leg 1 and 2 of the pot are tied together. I used the legs of the resistor to attach the pot to.

I removed the factory 22k resistor (to the right of the 220uf/63v bias cap, just above the 30uf/500v blue cap for the screen supply) and installed the pot assembly in the next "spot" over because it's easier to solder there... :lol: Electrically, it's the same connection.

Image

I have EL-34's in my amp. For really good reason, I "hardwired" the power tube socket board.

Image

Image

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