Circuitbenders Forum
Circuitbenders Forum => Parts, Components, Unbent machines & Junk => Topic started by: peter on May 26, 2009, 11:21:13 PM
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Hi there,
I'm looking for a dual gang 20K W pot for my project but just can't find one. Anybody knows if they actually exist?? I searched my ass off, but without any result.
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http://www.bargainshack.co.uk/product/Standard-Potentiometers-Pot-Lin-22k.html
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You're saying I could just use a lin dual gang pot? What about the W (curve, or what it means)?
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haha. I'm new to this and and still struggling with things. I'm trying to build me a stereo Tube Screamer and according to the schematic there's a 20K W pot in it.
Thanks for your reaction by the way!
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W doesn't mean anything in terms of any kind of curve i know of.
Wheres the schematic
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No, I've never come across a W curve either. If you use the wrong taper, the control will be a bit "all up one end". You may find that for the distortion control on an effect you need a reverse-log taper pot, which is pretty much impossible to get. There are a couple of clever tricks you can do with resistors though...
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great that you're helping me out with this! I really don't know where th W stands for. The curve thing is what i found looking on the net.
Here's the schematic. I got it from NEWTONE (http://www.newtone-online.nl/downloads/NewtoneScreamer.pdf), it's a dutch website. But i put the schematic here:
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...it´s the TONE pot
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Here's the Tonepad Tube Screamer http://www.tonepad.com/getFile.asp?id=81. I noticed that this one is using a 20K lin pot indeed.
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Looks very much like the tone pot is supposed to be linear. I don't see why you need a dual gang one though...
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I think I got the solution to my problem!!
I'm trying to make two Tube Screamers so i can run them in stereo to run my sampler through them. And in order to control both at the same time I'll need dual pots, else I'll be turning to many knobs..
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If your doing this in sterio keep in mind that you should get the best quality parts you can afford !
This meaning 1% resistors and capacitors and perhaps pairing your transistors aswell as maybe heatsinking your IC's.. Heatsinking might be overkill thou..
What I'm trying to say is that if you don't do this one channel might sound way different from the other in you production..
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You shouldn't ever need to heatsink the opamps in a fuzzbox. They're not developing any real power.
I'd be surprised if you could tell much difference between the left and right channels of a stereo fuzzbox, although it may be worth matching the four clipper diodes and the input transistors. Most modern components are far more closely matched than the ones used to build these old stompboxes *anyway* though...
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I got some AC188 transistors i'm using in some fuzz face clones, some of which have built in heatsinks, and they do sound kind of 'tighter' than the ones without heatsinks.
Although that could just be down to the wild variations in tolerances between individual transistors.
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You shouldn't ever need to heatsink the opamps in a fuzzbox. They're not developing any real power.
That's why I said that would be overkill :P
I'd be surprised if you could tell much difference between the left and right channels of a stereo fuzzbox
If your using germanium transistors you will sertanly hear it unless you match them..
Although that could just be down to the wild variations in tolerances between individual transistors.
Well they are germanium aren't they ;D
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I got some AC188 transistors i'm using in some fuzz face clones, some of which have built in heatsinks, and they do sound kind of 'tighter' than the ones without heatsinks.
Although that could just be down to the wild variations in tolerances between individual transistors.
Well yeah. AC188s are pretty old now ;-)
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Maybe it's late, anyway this site sells W 20k Pots, but not dual gang.
http://www.musikding.de/product_info.php/info/p718_Alpha-Potentiometer-20k-W-taper.html (http://www.musikding.de/product_info.php/info/p718_Alpha-Potentiometer-20k-W-taper.html)
I found on the net that "The “W” taper attains 20% resistance value at 50% of
clockwise rotation (left-hand)" where Log is 10% resistance at 50& rotation, so it's like midway between Log and Linear
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Maybe it's late, anyway this site sells W 20k Pots, but not dual gang.
http://www.musikding.de/product_info.php/info/p718_Alpha-Potentiometer-20k-W-taper.html (http://www.musikding.de/product_info.php/info/p718_Alpha-Potentiometer-20k-W-taper.html)
I found on the net that "The “W” taper attains 20% resistance value at 50% of
clockwise rotation (left-hand)" where Log is 10% resistance at 50& rotation, so it's like midway between Log and Linear
That's interesting about the W-law pots - I'd never heard of that before. As I think I mentioned earlier, 22k pots will be absolutely fine and will make no difference at all to the circuit.
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I've found that info on a catalogue on http://www.potentiometers.com (http://www.potentiometers.com)
This is the graph with all the standard pot values and the special ones
(http://img140.imageshack.us/img140/5101/potgraph.jpg)
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When is someone going to rename this thread from "can't find dual gang 20K W pot" to fuzzbox or something in that area ???
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When is someone going to rename this thread from "can't find dual gang 20K W pot" to fuzzbox or something in that area ???
its a mystery ;)