OK to Sub 100k Pot For 150K?

[hj808]

Hi- I'm hoping for some guidance about replacing the 150k volume pot in a 70's era Sansui solid state preamp with a 100k model.

This is a thumbnail of the circuit:

I am looking to replace the original pot with a motorized TKD pot, which looks like it can just shoehorn in the available space. The TKD is a 100k log pot, while the original is a 150k log pot, so I am seeking feedback on whether this lower value pot might be a viable replacement.

I am ignorant enough of the design theory here to not know what potential pitfalls might occur by dropping the overall value on the pot, and even with some pretty extensive research on the web, I don't have a clear idea of whether this would work without any problems.

Thanks for any assistance-

Herb

 

[bob91343]

It depends. You certainly won't damage anything, but it's possible it will have a very minor effect on distortion or frequency response. I'd need to see the circuit; your thumbnail won't come through.

 

[gyro]

Try series resistor?

If you've never needed to turn up the existing control to anywhere near maximum volume the you could try a 100k pot with a 47k resistor in series with the top end of the track. It might give you a bit better adjustment range for lower volumes too.

 

[hj808]

Hi- Thanks for the responses. I'm re-doing the circuit attachment to see if works as pdf.

The original pot would rarely be turned up more than halfway, so the 47k resistor on the ground leg may do the trick in terms of the circuit seeing an overall impedance close to the original value (if I understand things correctly).

Thanks- Herb

 

[infinia]

That's a specialized pot with taps for loudness, which is quite nice. Sorta is the 70's sound IMO. Use a 51K resistor from top of pot to PCB pins 15 & 16 (2 places).