250k linear pot needed

[scole]

mojo doesnt have cts 250k linear pots. i wonder if i can use a 100k linear and put a 150k resistor on the wiper lug?

[zhyla]

Eh... are you saying nobody manufactures 250kOhm linear pots? I kind of doubt that. Anyways, just use a 500kOhm instead. A 500k is capable of everything a 250k is.

[TheTinMan]

mojo doesnt have cts 250k linear pots. i wonder if i can use a 100k linear and put a 150k resistor on the wiper lug?

It really depends on the application. What is it? Is the pot being used as a voltage divider or as a variable resistor? Something else?

Either way, tacking a resistor on the wiper probably won't get you where you want to be. You can tack a 250K resistor across the outside lugs of a 500K pot to net 250K, but that will alter the taper of the pot.

You should be able to get what you need from AES or Hoffman.

Chip

[scole]

i guess i should have given some more info. its for the intensity pot on my blackface princeton rev project. i like the mojo cts pots. so i want the amp to have all the same pots in it. i could use an alpha. mojo just sends a 250k audio in there pr kit. i wonder if the trem would work correctly with an audio pot?

[zhyla]

i wonder if the trem would work correctly with an audio pot?

I don't think you're approaching pots correctly. The point is to be able to have a variable resistance between 0 and 250 kOhm. It can have any kind of hair brained taper you want as long as you're able to dial in the resistance you need. Audio tapers make volume control convenient as the taper matches your perception better.

[TheTinMan]

It's not a volume pot and linear taper works well for the Intensity control in that circuit. If it were my amp, I'd try the 250K audio in there and see if it worked OK for me - assuming I didn't have a 250K linear on hand.

Looking at the schematic, I'm not sure what a 500K pot with a 500K resistor across the outside lugs would do in terms of taper and/or the bias voltage. That's an example of a pot serving multiple functions at once. It's a voltage divider for the signal from the tremolo circuit (with the 27K resistor), but the bias voltage also goes through the pot.

No need to get hung up on matching pots IMHO but it's your amp.

Hope this helps,

Chip

[drdiode54]

250k Pots

Mouser electronics now stocks them

[Enzo]

And CTS linear 250k is stock number R-VC100KL at AES at $2.95



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