Both treble and bass potentiometers can be either the linear or logarithmic type. Sometimes I see diagrams with "logarithmic" and
sometimes with "linear" noted in the diagram and most of the time there is nothing said or written about its type.
Can someone here shed some light upon this subject please? Or supply some links where I can read about it?
Of course I know the difference between those potmeter types 🙂
but anyway....
sometimes with "linear" noted in the diagram and most of the time there is nothing said or written about its type.
Can someone here shed some light upon this subject please? Or supply some links where I can read about it?
Of course I know the difference between those potmeter types 🙂
but anyway....
the pots can also be Counter Clockwise logarithmic. It all depends on the designers circuit. Passive, active with a gain of 1 or active with a gain of 10. I used to build active Baxandall tone circuits with a gain of 10. This required CCW log pots. Nowadays with dacs and CD players outputting 2 volts a preamp with gain is not required.
Audio Tone Controls
RC Tone Control Circuit Calculator - Electronics Projects Circuits
google is your friend
RC Tone Control Circuit Calculator - Electronics Projects Circuits
google is your friend
Thanks multisync for your responses and those valuable links !
BTW : that Tone Control Circuit Calculator :
Have a little problem with this because I am using a Linux O.S for my computer. Perhaps I can do something using Wine.
BTW : that Tone Control Circuit Calculator :
Have a little problem with this because I am using a Linux O.S for my computer. Perhaps I can do something using Wine.
No. The true Baxandall is usually Linear. (A small S-curve could be more correct, and Bax liked a centre-tap, but we always use linear.)
Baxandall paper, 1952 (2MB PDF)
The James "passive" wants 10% "Audio" taper. (There are some variations but unless you are A Japanese Factory you can't get the odd tapers.)
james tone control - Google Search
James Tone Stack - Analysis
James Tone Stack - Create Your Own Design
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i thought linear pots were needed for the active circuits where the tone controls are in the feedback network and log or reverse log employed when the passive tone control circuit is used.
mlloyd1
mlloyd1
Wow, that is a really interesting remark. Can you elaborate somewhat more on this please?
The only thing I am aware of is that in audio amplifiers the volume control potentiometer must be logarithmic.
The tone control pots should be linear otherwise one end of the pot will be sensitive and the other end insensitive.
sorry, nope, haven't messed with passive tone controls since early 1970s.
🙂
here's a link to one version of the passive circuit:
A quality tone control circuit using opamp and few passive components
you can find the active (feedback) type anywhere.
you can use your favorite simulator to play with resistor ratios to simulate pot rotations.
hint: if you're looking for a good tone control design, look at the APT Preamp manual.
mlloyd1
🙂
here's a link to one version of the passive circuit:
A quality tone control circuit using opamp and few passive components
you can find the active (feedback) type anywhere.
you can use your favorite simulator to play with resistor ratios to simulate pot rotations.
hint: if you're looking for a good tone control design, look at the APT Preamp manual.
mlloyd1
Here's an active feedback tone control using Anti-log potentiometers.Some say it's neither Baxandal nor James so i wouldn't know exactly what to call it... https://www.diyaudio.com/forums/ana...hones-amplifier-equalization.html#post6324926
ESP pointed out that you can change a linear pot into log or antilog pot here:
ESP - A Better Volume Control
ESP pointed out that you can change a linear pot into log or antilog pot here:
ESP - A Better Volume Control
Yes, Nigel that makes sense! So linear is the way to go. BTW I am designing a passive Baxandall tone control
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It is a James network placed in the feedback path, which means that the log pots need to become antilog.
Pots in a Baxandall network are linear because of the equation the network obeys.
Did you read Baxandall's paper. He's all about the NFB.
Clearly most folks here do not want to think in terms of math. 🙁