Pot Taper mystery??

Started by Govmnt_Lacky, July 21, 2011, 01:24:44 PM

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joegagan

makes sense that the stereo fuzz wah from thomas used the same part as the std wah. i had one once, sold it unrepaired, never dove into it.
my life is a tribute to the the great men and women who held this country together when the world was in trouble. my debt cannot be repaid, but i will do my best.

Govmnt_Lacky

Let me attempt to dumb this down a bit for us "layman" peeps  ;D

Here is a link to some pot tapers on Sheet 2:

http://www.bourns.com/data/global/pdfs/PDB24.pdf

There are a LOT of curves for the 3 main pot tapers (Log, Linear, and Rev. Log)

So, which one of these is closest to the taper of your typical Wah pot?
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

ayayay!

Quote50% rotation = 102K ohms
75% rotation = 102.5K ohms
100% rotation = 103K ohms

Sorry, I've never seen a 100k pot with only 1k of variance on the last 50% of the travel!  I think you've got a bad pot.  My $.02.   :-\
The people who work for a living are now outnumbered by those who vote for a living.

Govmnt_Lacky

Quote from: ayayay! on July 25, 2011, 11:03:48 AM
Sorry, I've never seen a 100k pot with only 1k of variance on the last 50% of the travel!  I think you've got a bad pot.  My $.02.   :-\

You have now!  ;D

That is the measurement I took form my working HotPotz 2 100K that I took out of my working wah pedal.

A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

joegagan

#24
gvot lacky, you are correct.  yours has the exact same taper as the 50+ thomas and dunlop pots i have measured. 1972 through 06

edit : i shouldn't have used the term 'exact'. there is a range of where the taper starts, sometimes close to the middle sometimes all the way down on the 35 % Cw side of center etc. point is, the actual curve always plots out as the same taper, just starts at different points.
my life is a tribute to the the great men and women who held this country together when the world was in trouble. my debt cannot be repaid, but i will do my best.

Govmnt_Lacky

Quote from: joegagan on July 25, 2011, 12:44:21 PM
gvot lacky, you are correct.  yours has the exact same taper as the 50+ thomas and dunlop pots i have measured. 1972 through 06

Great Joe! Thanks for the confirmation.

Can you comment on my post above regarding which taper is closest to the Hotzpotz or the ICAR?
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

joegagan

trying to keep my posts accurate. everything i have said so far is from research. to answer your Q, i would have to go into excel and do an overlay and juggle stuff around to make the ratios jive and still be correct. at this time, i don't have the spare time to do it.
my life is a tribute to the the great men and women who held this country together when the world was in trouble. my debt cannot be repaid, but i will do my best.

Govmnt_Lacky

I graphed it out.

Odd taper  ???
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

joegagan

update.
i restored a 74 vox branded thomas stereo fuzz wah. ( never saw one with any other year made, i think they only made them in 74?)

they  indeed did come from factory with two different tapers. the ' regular' side had a regular crybaby pot , the opposite side had same taper but in reverse. made by centralab.
because there is no known modern crybaby condensed log taper in reverse, i used the same taper ( hotpotz2 by dunlop )for both sides. worked and sounded fine to me. the calibration of both pots relative to one another is absolutely critical , however.
my life is a tribute to the the great men and women who held this country together when the world was in trouble. my debt cannot be repaid, but i will do my best.