Best pot/cap combo for a single filtertron.

Jack Clayton

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I've modded a fender duo Sonic for a single filtertron in the bridge position. The core tone is awesome, but my only issue is that either tone seems to have a very uneven taper. I hear very little rolloff as I turn the knob, and then all the change occurs right at the end. Probably around 3 to 1 is the only useful place.

I'm using 500k pots with a .047 orange drop cap. Should I try a 250k pot? A .022 cap? Any ideas?
 

Boreas

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I've modded a fender duo Sonic for a single filtertron in the bridge position. The core tone is awesome, but my only issue is that either tone seems to have a very uneven taper. I hear very little rolloff as I turn the knob, and then all the change occurs right at the end. Probably around 3 to 1 is the only useful place.

I'm using 500k pots with a .047 orange drop cap. Should I try a 250k pot? A .022 cap? Any ideas?
What do you mean by "either tone"?

Assuming everything is wired correctly and soldered well, I would definitely stay with 500k pots if you like the "core tone". Changing values will alter that. What you likely need to investigate would be linear vs. audio(log) taper pots. The pot taper has everything to do with what you are describing. Sometimes a damaged or worn pot will work that way as well. How does it compare to the taper of the V pot?
 
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Jack Clayton

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What do you mean by "either tone"?

Assuming everything is wired correctly and soldered well, I would definitely stay with 500k pots if you like the "core tone". Changing values will alter that. What you likely need to investigate would be linear vs. audio(log) taper pots. The pot taper has everything to do with what you are describing.
Sorry. That was a autocorrect. Meant to just say "the tone"
 

Boreas

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Sorry. That was a autocorrect. Meant to just say "the tone"
Do you like the tone with the T pot at zero? If it is too muddy, you may want to try a .022 uf cap. It won't get as dark, but you may notice even less roll-off. Do you know what taper your installed pots are supposed to be?
 

Jack Clayton

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I honestly don't know what the taper is. They're standard 500k cts pots to the best of my knowledge.

I'm fine with how dark it gets at it's darkest. The issue is that only the last 30% of the knob sweep is useable.
 

Boreas

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I honestly don't know what the taper is. They're standard 500k cts pots to the best of my knowledge.

I'm fine with how dark it gets at it's darkest. The issue is that only the last 30% of the knob sweep is useable.
If you have pix of the back of the pots (including any codes), we may be able to figure it out. Often an "A" in the code indicates audio taper, but every brand is different. You may find this helpful:

 

tomasz

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You may have a treble bleed installed and not like it, that it retains the treble? If so, try to de-solder that for the start. I'd probably also consider a vintage taper pot, so the roll off is not that drastic - you would get a longer usable sweep. The cap value itself will probably not do much difference until you reach 3/4 of the sweep.
 

Jack Clayton

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You may have a treble bleed installed and not like it, that it retains the treble? If so, try to de-solder that for the start. I'd probably also consider a vintage taper pot, so the roll off is not that drastic - you would get a longer usable sweep. The cap value itself will probably not do much difference until you reach 3/4 of the sweep.
I honestly didn't know there were different kinds of taper. I thought the only consideration was just the 500k value of the pot. Thanks. This is helping.
 




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