Tonestack calculator - log a vs log b ?

[jmrckr]

Hello everyone. I came acrosse the duncan tonestack calculator and noticed that there is two different log type pots (log A and log B). I checked, for example, the alpha pots specs and they mention only one type of log pot ... so, what is the difference ?

What is the "standard" log type ? Are alpha log pots type a or b ?

[dorrisant]

"A" taper = audio
"B" taper = linear = log

Alpha pots, along with many others, come in these two standards as well as "C" and "W" for some... but you didn't ask about those.

[jmrckr]

Thanks for your answer. But what I mean is that in the calculator it seems like there is two different log/audio tapers (log type A and log type B) PLUS the linear one.

[pdf64]

The 'help' section advises that log A is 30%, log B is 10%.
The standard Bourns, CTS and European audio taper is 10%, Alpha USA is 15%.
See a Fender RI schematic for which taper is used in which position, unfortunately TSC has it almost all wrong.
Any Vox and Marshall audio taper should be 10%, not the 30% defaults in TSC.

[jabguit]

"A" taper = audio
"B" taper = linear = log

Alpha pots, along with many others, come in these two standards as well as "C" and "W" for some... but you didn't ask about those.

"Log" is short for logarithm, which linear tapers are devoid of.
"B" is as pdf64 stated - 10%.

cheers,

[ChopSauce]

By the way, anyone knows the "classical" analytical expressions for the log functions f, such as: R = f( angular_position )

There are many curves plotted on the internet but nobody seems to actually know them...