Need Replacement Potentiometers

[paul_g_787]

Does anyone in the UK here have 5k A (Logarithmic) Audio pots? Or know where I can get some? They are the PCB mount type. (See Photo).

I need to replace 2 in an amplifier as they are damaged, but CPC or eBay do not have the value I need, only 10k

[andy3055]

 Try Mouser or Digikey.

[LateLesley]

https://www.ebay.co.uk/itm/5-x-5K-Log-Logarithmic-Splined-Potentiometer-Pot/252483665839?epid=1478782301&hash=item3ac932ffaf:g:sGYAAOSwKIpV-dU4

[james_s]

In a pinch you can also put a resistor across two pins of a linear pot to get something pretty close to logarithmic. If you plot the curve of a real audio taper pot it's usually pretty ugly and only vaguely logarithmic anyway.

[paul_g_787]

https://www.ebay.co.uk/itm/5-x-5K-Log-Logarithmic-Splined-Potentiometer-Pot/252483665839?epid=1478782301&hash=item3ac932ffaf:g:sGYAAOSwKIpV-dU4

Hi. Thanks for the link. Unfortunately I need 20mm shafts to fit the original knobs back on and these are 16. I had come across that listing already.
Probably should have put that in OP.

[paul_g_787]

In a pinch you can also put a resistor across two pins of a linear pot to get something pretty close to logarithmic. If you plot the curve of a real audio taper pot it's usually pretty ugly and only vaguely logarithmic anyway.

That is a good idea! I have researched what you said and I see exactly what you mean. You have given me a slightly different idea though.

As I stated, I am able to get 10kA Log pots that are exactly the right size and shape. Just double the value I need.

And I know that 2x 10k resistors in parallel equals 5k

Could I put a 10k passive resistor in parallel with the outside pins of a 10k log pot and it still operate as a log pot?

[SeanB]

5k, 10k, in an amplifier as volume control it really does not matter that the resistance is double, it will make little difference, as source will not mind, and the input to the amplifieris going to be so much higher anyway.. in a tone control yes it will make a difference, so there you probably want to have the extra resistor across the outer terminals, and accept that there will be differences in the value between the wiper of the 2 variants.

[james_s]

Play around with it and see how whatever you're thinking of trying behaves. You could use a real breadboard and multimeter if you want, or just simulate it with something like this https://www.falstad.com/circuit/

[mikerj]

Bournes 5k A2 taper, 20mm splined shaft

Datasheet.