Help with buying potentiometers

if837 · Joined: Apr 12, 2009 Posts: 56 Location: sweden

I found myself very confused when I sat down and tried to ordered
potentiometers. I thought that when the word TAPER is used, it´s a
Audio Taper and I should order or look for LOG potentiometers.
Now I found that there is both Linear Taper and Log Taper potentiometers.
In the partlist the word Audio never shows up just Linear Taper.

Anyway this is what I came up with, and I want to check with someone that
has build Ray´s DIY modules before.

Does this look right ?

VCO: 100K LIN - 100K LIN - 100K LIN
VCA Dual Log/Linear: 100K LIN - 100K LIN
VCF Four Pole 24 db: 100K LIN - 100K LIN- 100K LIN - 100K LIN - 100K LIN
ADSR: 100K LIN - 100K LIN - 1M LOG - 1M LOG - 1M LOG
NOISE Cornucopia: 100K LIN - 100K LIN
LFO voltage controlled: 100K LIN - 100K LIN - 100K LIN

if I deside to ad another VCO, what kind of mixer (MFOS) do I need to ad ?

RF · Posted: Tue Jan 12, 2010 3:40 pm Post subject:

I used linear on all pots for my MFOS stuff.

If you use the same filter for both VCO's the mixer in the filter will be fine.

Otherwise he has some simple mixers in his synth resources section
http://www.musicfromouterspace.com/analogsynth/monomixerpage.html

bruce

if837 · Joined: Apr 12, 2009 Posts: 56 Location: sweden

thanks for helping me

fluxmonkey · Joined: Jun 24, 2005 Posts: 708 Location: cleve

Looks right to me... on the ADSR, R16, R22, R17 are specified as log taper; everything else looks to be speced as linear. You could use linear for all, but I think the logs will give you a better feel on the envelope.

Log and audio taper pots are the same thing; sometimes they're even referred to as expo or exponential. If no taper is specified, it's usually safe to assume that means linear taper. Circuits will work with either one--if i have the right value but the wrong taper on hand, i'll use what i have and swap it out later if the feel bugs me.

The filter has a built-in 3 input mixer on the front end; ray's front panel diagram includes a separate level adjust pot for all 3. (and just to confuse things, i generally use log pots for audio level controls like mixers. personal preference)... a lot of folks get by with just that to start out with.

If you do want a separate module, but think the MFOS stereo mixer is overkill, and you don't want to etch your own board, another option for a simple standalone mixer is Ken Stone/Catgirl synth (http://www.cgs.synth.net/); either the CGS04 or CGS23... these can be used to mix audio or CVs, and are a bargain.

good luck!

b

if837 · Joined: Apr 12, 2009 Posts: 56 Location: sweden

thanks bbob for very clear and helpful reply. I will print this out and save it.