audio taper potentiometer

Jun 09, 2007 17 Replies

Hello all,



I want to change a linear 50k pot to an audio taper 50k pot in my Fender Blues Junior guitar amp. Do you know where I can find such a potentiometer ? I have try to find it in Farnell catalog, with no success ...



I have put some pictures:

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Thanks very much !



Olivier



Ask in alt.guitar.amps

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This should be a common item, a PC-board-mounted audio-taper potentiometer. It may be nominally 47k instead of 50k and might be called log taper rather than audio taper (similar but not identical). What part of the world are you in?

surface mount piece is a bitch to replace.

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A *certified" Fender repair shop would be TOO obvious.

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I am living in Belgium. They are less and less electronics shops, so generally I buy my components at Farnell. But here I do not find any references ...

Is there a manufacturer's name on the potentiometer? If so, Google for it, and find a distributor.

Let me suggest another approach. Add a 27k or 47k resistor from the wiper (middle contact) of the potentiometer to the low end of the potentiometer. This is a very old trick for making a linear potentiometer behave more like an audio taper. It's not perfect, but it may achieve what you want.

Also, write to the people at

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and see what they know.

And look at

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which is probably the manufacturer. If you can identify the part you want, they can probably tell you where you can buy it in small quantities.

Hi MC,

Cool, I think it is a CTS Corp Series 296. I will contact them. Thanks very much. Olivier

Only if you find a AT pot to fit in the socket..

You could tap off the LT pot and adjust the 'bend' where it changes to promote an audio able 'ear friendly' taper. Is what you want to do going to happen with a taper change? Is it worth it?

JJTj

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It's been a *long* time, but I believe that an audio taper pot is ANTIlog, not log. A log pot will work only if you hook it up to get louder as you crank it CCW.

Isaac

pictures:

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So-called log pots arent really log. Theyre linear over most of their scale, with a short section of lower R per distance material at the bottom end. It may be quicker to reduce the R of the bottom 10%-20% of the track than find a replacement. This could be done with some graphite dots at the edge of the track, where the wiper doesnt go. Graphite is very conductive, so use only the tiniest amout, and dont get it on the side of the track base, where it coudl conduct to case.

NT

It's not surface mount.

It has standard PCB tails.

Graham

Not as I understand it.

Linear taper = output voltage proportional to rotation

Audio taper = lower at mid-scale than linear

Log taper = same, slightly different curvature (not truly logarithmic because there is no logarithm of 0)

Antilog taper = higher at mid-scale than linear

To make it get louder instead of softer as you turn it CCW, you reverse the connections to the 2 ends of the potentiometer, whichever taper you have.

Your Farnell Belgium part number is the same as in Australia (and the rest of the world) - 1191756

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Wrong size.

Graham

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I see no indication that that one is audio or log taper. Is it?

the

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'A' taper is audio taper. The 50KA Alps is audio taper - that is why the A at the end.

the

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The OP's pics look like a 9mm pot to me - and so is the Alps pot which I linked to.

It's not.

The 9mm types all have a 'sealed' body. His doesn't. 12mm I think.

Graham

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