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vol.pot question

8/13/1997 12:07 PM
Scott Davey
vol.pot question
I'm not happy with the feel of the volume pots on my Tele Custom (prob.  
250k). All the action, particularly in blending both pu's, is from 9-10 on  
the knob. As I understand it audio, taper has slower change at the top  
than linear or reverse audio, in other words this is the best I can get.  
My suppostion is that a larger value pot might be even worse in this  
regard. Any comments or corrections?
8/18/1997 2:15 PM

Are you sure that your pots are audio taper, not linear? It sure sounds like linear to me.
8/27/1997 11:27 AM
Scott Davey

Right you are, R.G.! I found out that the '73 Tele Custom for some odd reason came equipped with linear pots! They'll be gone shortly.
8/28/1997 7:55 PM
Bill Bolton

> came equipped with linear pots! They'll be  
> gone shortly.  
Make sure you keep the originals, in case you ever want to sell the instrument. Collectors go crazy over things like "original components", even if they are sub-optimal from a usability point of view.  
8/30/1997 6:50 PM
Mark Hammer

Good point Bill. Have you ever seen some of the ads in Vintage Guitar Player for these things? I think if I ever wanted to turn evil, I'd print up an ad with virtually untraceable things like "1963 bridge plate screws, $150". If you ask me, the ads for "vintage tone control caps" are kind of suspect. Exactly what *is* the difference between a crappy ceramic .02 disc cap made in 1958, 1969, 1977 or 1997, other than maybe the older ones aren't up to spec?  
On a more congenial front, there was an article in the european magazine Elektor some years ago about changing the taper of pots by soldering in resistors between the wiper and one or both of the lugs at either end. The maximum value of the pot would be set by the parallel resistor(s), with the requirement that the original pot be replaced by something with a higher value (since the parallel resistor would effectively reduce the overall resistance). I'll see if I can find it in one of my binders and distill some rules of thumb. If memory serves, the article indicates a variety of options for creating all sorts of non-linear tapers.  
9/2/1997 10:12 AM

Good point Mark. I titled my post to alt.guitar.amps for the line voltage reducer setup "Vintage AC Power for Your Amp" or similar.  
The tricks with tapering resistors work well in the special case where you are using the pot as a voltage divider (volume control use is the perfect example) and not at all where you are using the pot as a variable series resistor (LFO speed controls being the example).  
You can't make reverse log pots for speed controls by using tapering resistors.
9/12/1997 2:27 AM
Steve Ahola

Here's an old trick from Dave Schector that I've used many times on linear pots in guitar controls:  
Add a resistor that is 1/4 the value of the pot between the wiper and the ungrounded terminal. That will approximate the response of an audio pot for a non-critical application such as a guitar tone or volume control. I've also used that trick to simulate a reverse taper audio pot.  
If my memory serves me well, the Schector OmniPots from the 70's and early 80's had linear tapers so Schector had to come out with that mod to be able to sell them...  
If you decide to change out the pots, I'd suggest that you try 500K instead of 250K for a slightly more aggressive tone.
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