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Vintage threads from the first ten years

bias pots

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9/11/2000 11:25 PM
DavidB	bias pots where can one get good bias pots? I have been using Fender style pots but would like to use something mounted on the board like a 70's Marshall. thanks David

9/12/2000 1:58 PM
Liam	Marshall used quite low cost presets, available in all of the bigger electronics catalogues. (In the UK that's RS, Maplin, Farnell, etc., but I assume you're in the US, Mouser?.)

9/12/2000 8:17 PM
DavidB	Yeah,in da US sir.You be right Mouser has alotta stuff but I'm not sure what would be suitable.bought samples of cermet pots but they are flimsy,the leads that is.the search continues! db

9/29/2000 12:38 AM

Here is my 2¢ on the subject; potentiometers drift and I don't like that at all. Mouser has a multi-turn pot that works much better than a cheapie that will not keep the bias voltage steady. This seems to me to be a reason people don't like biasing with a 'scope, claiming if set a few times over a short course of time will yield different results! Try the multi-turn unit; it's nice and steady and I like 'em a lot.

9/29/2000 11:03 PM
DavidB	Thanks Randy,which multiturn do you recommend?

9/30/2000 1:17 AM

I've been using the 594-70Y203. It's a 20K/20 turn pot rated at 1 watt and measures 1 1/4" long. One costs me $5.25, and you gotta buy 25 to get them down to $5.10, so 'buddying up' to save 40¢ isn't worth it. They work nice for me; smooth and accurate. I chose 20K just on a lark that one turn would increase/decrease the resistance 1K. Not very clever, but at the time I thought it was.
P.S. Get a catalog and do some shopping. They just jacked up their minimum order to $100, but it took me about 5 minutes to spend more than twice that.

9/30/2000 1:30 PM
DavidB	Thanks Randy,how thick are the leads on the model 70 pots?I bought the 43 Spectrol and I don't trust the skinny lil legs on em!I use eyelet boards,will the 70's legs fit?sorry for all the questions but the bias pots have been the biggest pain besides getting chassis made! Regards David

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