Volume taper

[oleoleo2]

Hi Diyaudio forum.

I am trying to build a guitar distortion fx. On some part of the amplifier circuit I have a JFET amp-circuit with a 100KA pot at the output to control the volume. The pot leads the signal to ground when it is turned. I am not very satisfies with the way the taper feels. It is like it turns the volume up a lot in the beginning and the gets more and more passive. As I understand the 'A' means that it is logarithmic? Have tried with linear pot's to, it is almost the same. I suppose this must be a problem a lot of others run into? How do I solve this?

Kind regards,

oleoleo2

 

[DF96]

It depends on how old the pot is. "A" used to mean linear, but now means log (what committee dreamt that up?). See Potentiometers (Beginners' Guide to Pots).

You could try measuring the resistance at half-travel. If half the total it is a linear pot. If 10-20% of the total it is a log pot. Of course, you can connect a log pot the wrong way round (and there are anti-log pots too).

 

[mjf]

.........not easy without schematic............

perhaps you try out a resistor in series with the pot..........

 

[wakibaki]

Replace it with a 100k linear pot and a 15k resistor as on this page: ESP - A Better Volume Control. Or use the existing pot if you can determine that it's linear. The first thing to try is setting the pot to half-way and measuring for 50k. If you don't get 50k then swap the outside connections on the pot and see how that works. If you do get 50K then try the dodge with the 15k connected to the wiper and ground

w

 

[oleoleo2]

It depends on how old the pot is. "A" used to mean linear, but now means log (what committee dreamt that up?). See Potentiometers (Beginners' Guide to Pots).

You could try measuring the resistance at half-travel. If half the total it is a linear pot. If 10-20% of the total it is a log pot. Of course, you can connect a log pot the wrong way round (and there are anti-log pots too).

Well it seems like it's a linear pot then as I get 50R halfway (thanks for the "trick" funny I never though of that )

 

[oleoleo2]

Replace it with a 100k linear pot and a 15k resistor as on this page: ESP - A Better Volume Control. Or use the existing pot if you can determine that it's linear. The first thing to try is setting the pot to half-way and measuring for 50k. If you don't get 50k then swap the outside connections on the pot and see how that works. If you do get 50K then try the dodge with the 15k connected to the wiper and ground

w

Thanks a million! This seems to the trick!