Potentiometers: what do you suggest??

Lenox (Buck) Buchanan lbuchanan at qualcomm.com
Tue Jun 10 18:28:32 CEST 1997

Hi all,

Sorry for being so late on this thread.... and aside from the debates about
Mouser verses Radio Shack parts.....

At 08:03 PM 6/4/97 +0100, prof. Antonio Guerrieri wrote:
>I'm sure that potentiometers are important pieces of electronic components
>to be considered when building synth modules and/or when they are dedicated
>to the control of important parameters like tuning and so.
>Please, can someone suggest me some important features to be used for them?
>in which synth module and /or for what control particular selection is

As a rough general rule, use a linear taper pot for times when you want to
control things not directly related to human perceptions of "loudness" and
pitch.  For example,  CV attenuators, time delays, pulse width, etc should
*usually* get linear control.  Due to the exponential nature of human
perceptions of loudness, log taper pots are usually best for volume controls
and the like.   Note that there are likely exceptions to these rules.
Personally I have found that since we are building musicial instruments and
not test equipment, it is best to experiment with both tapers in any dubious

But the questions I have is: What is the consensus on pitch related controls
such as filter cut-offs and audio oscillator frequencies.  I've used a lot
of linear pots for these things but I could see why a log taper would be
nice too.  How do others on the list feel about this?

>can someone suggest or recommend also (not least important) some

When I put all the trouble and effort into designing and building something
from scratch, I don't like to skimp on parts quality unless I need to.  So I
prefer going with Clarostat, Spectrol, or Bourns brand pots when I can
afford them.  Most of these pots (depending on model) are very rugged,
sealed, mil-spec, etc.  But they're also expensive 5 - 10$ per unit and
harder to get in log tapers.  I also found out (the hard way!!!) that the
Clarostat RV4 series pots (and probably all Clarostat models) have a back
cover material (probably aluminum) that cannot be soldered too.  If you
don't want to solder to the back, the RV4 models are only 5$ each from
Digi-Key and are a happy medium between the ultra expensive stuff and the
cheap stuff.

On the Mouser vs. RS debate, I have found that the RS pots don't seem that
good while the Mousers are my choice for  "good quality in a cheap pot."  

But hey, this is all just my two cents.  I'm interested in anyone else's
opinion on these issues.  Take it easy all!


Buck Buchanan   x84377
Engineering Tech. - TGP dualband

"The junk merchant doesn't sell his product to the consumer, he sells the
consumer to the product.  He does not improve and simplify his merchandise,
he degrades and simplfies the client."    - William S. Burroughs, 1959

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