Good value for post-fooger vol pot?

The Moog Forum Moogerfooger Forum
1

Can someone tell me a good value to use for a volume pot to put after my Moogerfoogers in a passive effect loop? I’m thinking just of a box with two jacks and a pot, to let me trim the volume back. What value of pot is optimum relative to the output expectations of the MFs?

Also, if there are any other components I should add to make things more transparent, please let me know. Thanks…

2

Instead of making one, you could simply buy something that would do the same job very cheaply. Take a look at the ART PowerMix passive mixer:

http://www.musiciansfriend.com/product/ART-PowerMIX-l-4-Channel-Mixer?sku=180623

Using just a single channel, it can serve as a simple outboard volume pot. Might be all you need.

3

That’s an idea to keep in mind. The problem is that I’m also trying to save a little space on the board, so I’d like to avoid unused channels if possible.

4

I just use one of the attenuators on my CP-251.
Works like a charm.

Randall

5

I understand the desire to keep things small, but the ART PowerMix box I suggested is only 3 3/4" x 3" x 1.5", and it’s $30. You could use some right-angle jacks to keep the smallest possible footprint, and still have the luxury of summing four channels if you ever need to.

BTW, the ART box uses four 47K ohm pots, but you could easily get away with using a single 10K ohm pot if you decide to build something.

6

strata – your message got me very excited! But then I tried it out, and discovered that on my rig, whenever I plug the effect loop return into any of the attenuator outs on my CP-251, there’s a quiet but very noticeable high-frequency whine. The sound of this is completely independent of any knob settings, and is the same on all attenuator out jacks, whether or not there’s anything patched into them. So I guess while my CP works great for mixing CV, and for mixing audio for use as CV, it’s not going to work for mixing/attenuating audio for use as audio.

Thanks for the idea, though, and I may keep playing with it. But does anyone at all have an answer to the original question? If I just want a volume trim pot in series with the last MF, what value would be good? Or does it matter?

7

Greg — Thanks again, you might be changing my mind. And thanks also for checking the pot values on the Art: that gives me a good starting point.

8

narrowcaster,

I just use one of the CP-251’s attenutors as the last stop before my effects loop return. I don’t get any whine or I wouldn’t use it. :smiley:

Randall

9

Randall – Yeah, that’s what I tried. There must be something different about the setup of our loops, or our CPs. I think I’ll start another thread to ask about this…

10

Noise problems:

If you are using a daisy chain, you could try and use a separate power supply for the CP. Maybe you’re drawing too much current or another unit is interfering. Try swapping the supply anyway.

An attempt at the original question:

Larger value pots provide better attenuation. You can “reduce” the volume more
But if the value is too large, you lose resolution. I.e. you might restrict the useful range of the knob.

I would expect a value of somewhere between 10k and 100k would be the most useful. And probably go for a log pot, not linear.

11

Thanks latigid. I’ll try a separate power supply and see if that helps. Right now everything’s being powered from a Voodoo Labs Pedal Power II. If that doesn’t clear it up, I’ll start a new thread.

Thanks also for the pot explanation. I ended up using a 50k, and it works fine. All they had in the mall was linear taper, which is a little frustrating but OK for the application (no sweeps, just set and forget).