Neo Vibe Speed Pot Questions

Started by Kevin Mitchell, August 13, 2014, 12:44:00 PM

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Kevin Mitchell

Yes there are many threads about this taper but I feel that some facts are still a bit unclear. I also didn't find the "vibeupdate.pdf" to be clear enough to ease my worries.

So I'm about to be working on my 2nd pedal build and I have chosen a Univox Univibe clone "Neo Vibe". Looking at the parts recommended I am confused about the function of the Dual Reverse 100k Log Pot and it's explanation.

Here are my questions;
If I mount a dual pot onto the enclosure like the rest of the pots (not in a foot pedal) should it be a reverse or normal taper?
Using a reverse audio(log) for a surface mounted speed control doesn't make sense to me, the bunched side of the control would be at 7'oclock apposed to 5'oclock (opposite end) If I am understanding audio tapers correctly

If I use a normal (not reverse) dual audio taper could I simply mirror the wire diagram and will I get the correct effect? Or is that already demonstrated in the diagram? Uhhg confusing  ???

I have found vendors for all types of dual tapers so sourcing them isn't an issue. Although Smallbear seems to be the only one to have the correct reverse tapers.

If anyone could clear up some details for me I'd really appreciate it. My brain is trying to reason with conventional physics and I really don't know what part fits my need.
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R.G.

Quote from: Kevin Mitchell on August 13, 2014, 12:44:00 PM
If I mount a dual pot onto the enclosure like the rest of the pots (not in a foot pedal) should it be a reverse or normal taper?
Reverse.

The nature of RC networks and how they interact with speed controls makes reverse log seem more "linear". If this is confusing, use a linear pot of about 10X the suggested one and taper it with a resistor.

QuoteIf I use a normal (not reverse) dual audio taper could I simply mirror the wire diagram and will I get the correct effect? Or is that already demonstrated in the diagram? Uhhg confusing  ???
No, mirroring the wiring diagram will reverse the electrical change per rotation with respect to the rotation. However, this now converts the "speed" pot into a "slowness" pot, with maximum "slow" when the knob is fully CW.

R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

Kevin Mitchell

Thanks R.G. that clears the air a bit.
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