RCA AR77 - Sensitivity Control Replacement

[tim]

Hi,

Need the forums advice on replacing the sensitivity control pot (R21) on a RCA AR77. The original has long gone and replaced with what looks like a cheap guitar pot. Looking at the schematic the original value was 30k. I've been told to use a linear pot with reverse audio taper. Unsure what the correct replacement should be. Can anyone in the forum advise?

Cheers,
Tim

[Radio Fixer]

"a linear pot with reverse audio taper" , that to me is a reverse log pot in UK speak.

I cant advise on what the original was but Blore Edwards will make you a pot with the right law and spindle etc. Very good and helpful.

You may do better asking on the US ARF.

Gary

[pwdrive]

I'd try a 25k lin.

Lawrence.

[ppppenguin]

Linear and reverse audio are 2 different types of pot. As has already been suggested I'd try a 25k linear and see how it works. The modern value of 22k should also be ok. Except in a few specialist applications pot values are rarely critical.

There are ways of simulating non linear pots by connecting a resistor from the wiper to one end.

Obviously it would help to see the schematic.

[tim]

Many thanks Gary, Lawrence & Jeffrey for responding to my post. I'll go try a 25k linear pot.
I have attached a screenshot of the schematic to help put it into context.

Tim.

[ppppenguin]

I'd be tempted to try a 47k or 50k pot. Then you can tweak the law a bit with a resistor if necessary.