Vibrato and Wet/Dry Mix mods for Small Clone

Started by trotskyismyniece, June 12, 2009, 12:26:23 PM

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trotskyismyniece

So I've been trying to figure out the vibrato switch mod for the Small Clone, and it seems like the only source for it was experimentalistanonymous, before it went down.  I can't really find anything really clear on it, but the only thing I could glean was a suggestion that switching off the 22k resistor does that.  I tried it and it just makes the pedal clean! There was also a mention of a 33k resistor but there's three of those so I'm confused.   Also, it seems that since taking the 22k resistor out of the mix makes the pedal clean could I replace it entirely with a 50k pot (with a resistor wired in to lower it closer to 25/22k) wired as a variable resistor for a wet/dry blend?

slacker

#1
On the tonepad schematic the dry sound goes through the first opamp (IC1a) then along the line with Point A on it to the 22k resistor. The wet sound goes through the MN3007 and all that other stuff then past point D to the 20k resistor. Those 2 resistors mix the wet and dry sounds.
If you remove the 22k resistor next point A that will kill the dry signal, leaving just the wet, which gives you the vibrato effect. If you remove the 20k resistor above point D you kill the wet signal and get just the dry. Sounds like that's what you've done.
To do a dry/wet blend pot remove those two resistors and replace them with a 47k pot one outside lug goes to point A the other one goes to point D and the wiper goes to the point where the two resistors used to join.
You might also need to mess about with the value of the 33k resistor in the last opamp stage to keep the volume the same after doing the mod.

Hope that makes sense :)

lowstar

i used a 250k revlog pot before the 20K resistor (wet side) to do the trick; with the pot full on, you have about 50/50, backing off the depth pot yields more of the dry signal. rev log is better suited for these controls, it gives a nice dispersion along the pot travel (the boss ce-2b depth control also uses rev log).
works like a charm; makes the effect so much more useable for bass guitar.

cheers,
lowstar
effects built counter: stopped counting at 100

flintstoned

Just updating an old thread for future searchers looking up this mod. I tried the method of replacing the 20k and 22k resistors with a 50k pot and there was a huge jump in volume on both sides of the sweep. I replaced the resistors and then wired in a 1k pot after them and it works perfect. Full dry on the left and full wet to the right. This thing makes some pretty sick sounds with a depth pot mod added and all 3 knobs maxed out! REALLY SICK!
I forgot what I was gonna say here.

blowncone

i don't quite understand how that 1k pot achieves the effect you describe. if you wire the output of each resistor to the sides of the pot, you'd essentially have a mix range of 20k:23k - 21k:22k.. right? that ratio sweep would barely be audible.

is there something about the way you've connected this magical 1k pot that i'm missing?

dustintakk

Resurrecting an old thread because I'm curious as well about the 1K Pot mod posted by flintstoned.