potentiometer log?

[audiofan]

I was reading on DUNCAN'S AMP site stuff about tone stack and tone stack calculator ( very nice program ) but someting is still a mistery for me, the difference betwen LOG A an LOG B is log B a reversed log ? or is log B a different taper ?

As far as I know:

LINEAR taper is a taper that gives around50% of resistance at 50% of mechanical rotation,

LOG A or audio taper is a taper that gives around 10% of resistance at 50% of mechanical rotation,

But LOG B I dont know

[Bobken]

Hi,

This is a new one on me too, so I looked at a reversed-log pot I have, and it shows nothing on it except the value 10k!

It seems that in certain parts of the world, log and linear designations (A & B) are used in reverse.

According to the Farnell catalogue "Please note the Alps taper designation is opposite to standard European versions. i.e Linear is B taper, Logarithmic is A."!

Having said this, the only "reversed-log" pot they list has the prefix "RD Taper" as opposed to "A taper (logarithmic)", or "B taper (linear)", so make of that what you will.

You are certainly correct in that linear taper pots should ideally have 50% resistance at 50% rotation, and that log pots will show a much different value than this at the half-way point. I am aware that log tapers do vary in their resistance 'response' curves, and (at some time ago) users could choose a different taper, relating to severity of this 'response' curve, to suit their specific purposes.

However, I haven't seen any of these listed by manufacturers for many years, so I cannot check how these were designated.

Sorry this isn't a definitive answer, but maybe Duncan Amps will tell you if you mail them.

Regards,