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Topic: Claristat Pots |
Jim Saunders
From:
Houston, Texas, U.S.A.
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Mike Wheeler
From:
Delaware, Ohio, USA
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Posted 15 Nov 2018 11:54 am |
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That's not a complete link. You need the whole line, Jim.
_________________
Best regards,
Mike |
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Jim Saunders
From:
Houston, Texas, U.S.A.
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Posted 15 Nov 2018 2:24 pm Thanks
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| Thanks, Mike. I'm no whiz on a computer. |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 15 Nov 2018 10:10 pm
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Jim, that's a linear taper pot, won't really work for volume pedal. Too bad, because those older Clarostats and AB pots are THE BEST, but they gotta be Audio or Log taper.
B |
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Jim Saunders
From:
Houston, Texas, U.S.A.
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Posted 17 Nov 2018 5:36 am Thanks
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| Thanks, Brad, but what would you use this type of pot for? (Bad grammar. but valid question). What's it's purpose? |
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Jim Saunders
From:
Houston, Texas, U.S.A.
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Posted 17 Nov 2018 5:55 am Thanks
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| Thanks, Brad, but what would you use this type of pot for? (Bad grammar. but valid question). What's it's purpose? |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 17 Nov 2018 7:29 am Re: Thanks
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| Jim Saunders wrote: |
| […] what would you use this type of pot for? (Bad grammar. but valid question). What's it's purpose? |
Mainly voltage dividers and tone controls.
Also possible to turn them into "semi-logarithmic" volume controls by adding a resistor from center-lug to GND. |
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Jim Saunders
From:
Houston, Texas, U.S.A.
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Posted 17 Nov 2018 8:06 am Thanks
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| O.K., Thanks for the informed answer. Makes sense. But, I have bought two of them and if anyone would like them, I will mail them to you for a Forum donation of your choice. |
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Jack Stoner
From:
Kansas City, MO
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Posted 17 Nov 2018 8:52 am
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I've seen posts on here of someone using a linear pot. Not something I would do.
FWIW I don't even like the taper on the Dunlop replacement pot. Another reason I have a Hilton VP. |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 17 Nov 2018 12:55 pm
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| Jack Stoner wrote: |
| ...FWIW I don't even like the taper on the Dunlop replacement pot. Another reason I have a Hilton VP. |
They sure don't make pot tapers like they used to. Back in the day before digital, and back in the day when many designs were for industry and military-spec and NASA, they knew how to make a pot with a truly smooth, logarithmic (audio) curve/taper. But these days, most "audio" pots are made with only two segments of resistive material for the rotary track. So you essentially have two straight ramps with a kink in the middle where the slope becomes steeper. Back in the day, they would use 5 or more resistive segments which really does create a nice and rounded curve. Like Jack said, the Hilton is able to get a truly audio tapered curve with his design using an optical gradient filter.
Good old Clarostat or AB audio pots are like gold to pedal steelers that like pot pedals.
B |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 17 Nov 2018 2:29 pm
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That is where the "loaded linear pot" comes to the rescue 
One resistive segment (no kinks), loaded by a resistor to GND of about 1/7 the value of the pot itself, will get near the real 1:10 logarithm (lower stipled curve on illustration below). How near to that curve it gets depends on the pot's linearity and the exact value of the resistor.
Negative side is that such a "loaded linear pot" need to be built into, or be surrounded by, buffer-circuits in order to stay true to the chosen logarithm, but that is (surprise, surprise) true for s.c. "logarithmic/audio pots" also and they will never be truly logarithmic no matter what.
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Randy Schneider
From:
SW New Mexico, USA
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Posted 17 Nov 2018 3:12 pm
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Georg,
Your discussion of the 'logging' of the linear pot reminded me of this article I saw some time ago. Some may find it and the graphs interesting.
The Secret Life of Pots |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 17 Nov 2018 4:28 pm
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| Randy Schneider wrote: |
Georg,
Your discussion of the 'logging' of the linear pot reminded me of this article I saw some time ago. Some may find it and the graphs interesting.
The Secret Life of Pots |
Close enough…
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 18 Nov 2018 3:09 am
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| Good, old-style pots are still out there, they just cost more. I'd also strongly recommend that any pot with a removable cover be lubed before it is installed. That's the only way to get maximum life. Lastly, be aware that (military designation) part number RV4NAYSD504A would indicate a linear pot. The correct mil-number for a logarithmic pot would be RV4NAYSJ504A. |
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Jack Stoner
From:
Kansas City, MO
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Posted 18 Nov 2018 3:18 am
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| The Allen Bradley pot used in volume pedals was not a straight audio (logarithmic) pot. It was a modified logarithmic. That's why, to me, the current audio pots such as the Dunlop do not copy the feel of the AB's. |
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Steven Paris
From:
Los Angeles
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Posted 18 Nov 2018 3:22 am
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As Georg mentioned, you can make a very GOOD log pot out of a linear one and a resistor:
http://sound.whsites.net/project01.htm
_________________
Emmons & Peavey
Last edited by Steven Paris on 18 Nov 2018 12:55 pm; edited 1 time in total |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 18 Nov 2018 11:03 am
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Or...you can wire another (cheap linear) pot in place of the resistor, and have yourself an adjustable-taper pot pedal!  |
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