anyone familiar with the mutron wah?

[freeradical24]

i just got one and the effect sweep ends before the the  pedal completes its range of motion any one know how to adjust it without bending the piece of metal that passes through the optic sensor.
also i finished my first pedal the univox superfuzz and it sounds great !thanks to all who answered my questions.

[freeradical24]

i cant find any info anywhere else so............

[freeradical24]

anyone?

[ian87]

hey man. this forum moves pretty slowly, so sometimes it takes a while to get a response. but it's not cuz we don't love you.....

i had a mu-tron vol-wah for a while, and absolutely loved it. in fact, i wish i'd never ever sold it!

it employs an optical sensor, so the only way that i know of to adjust it is to vary the amount of light that goes to the collector bit, which probably entails bending the metal thingie of which you speak.

there may be other ways, but none that i know of. ...

-ian

[BillyJ]

A guess but perhaps a differnt value for the resistor feeding the LED or whatever light source it uses?
Maybe it isn't strong enough at that end or maybe not strong enough..

[Processaurus]

I recently stumbled across one of these in the local shop, and got it cheap cause it was distorting in a weird way.  It was an easy fix, but unfortunately I bent the metal thing you mentioned getting it apart (I have no clue how they put it together in the factory, it was awful trying to get the pcb out) and the taper on mine is now out of adjusment just like yours, it comes on fast and then nothing changes for the last 1/3 of the sweep.
The basic mechanism for the pedal is an LED shining on 2 photo resistors (one for vol, one for wah) and the metal thing connected to the rocker pedal shades the photo resistors,  changing their resistance.  On my schematic it shows a 3rd photo resistor, this one stuck inside the plastic lense module with the LED.  There's an elaborate circuit just for driving the LED, that includes this 3rd photocell and also a trim pot.  I have yet to try fiddling the trimpot, I can't figure out what it does by looking at the schematic.  It may adjust the brightness of the LED, which in turn may possibly change the taper of the pedal's sweep(?).
There are two trim pots, the one that is part of the LED driving circuit and another one that sets the volume between when the Vol switch is turned on and off.   It might be worth messing with the LED trimpot, I would note were it is currently set and put it back there if it doesn't seem to change anything.
-Ben

[freeradical24]

i figured it would be one of the trims.i wish i could find some info on this pedal.ive done every sort of google search i could think of of and nothing.
its like theres a conspiracy to keep every thing about this pedal secret.
oh well..

[freeradical24]

well i fiddled with the trims to no avail.then i noticed a piece of adhesive on the formention piece of metal in the path of the optic sensor(it apeared to belong there) i removed it. my sweep was full and wide but in volume mode it didnt even come close to cutting the volume when it was supposed to.so i put the piece of adhesive on so that it covered less of the sensor than it did previously.the wah is still wide and when in volume mode the signal bleeds through just a bit (with my dual showman cranked to ten i can hear it.)this is acceptable to me but i would like to have it working perfectly(300$!!!)
 if anyone knows where i could find a schematic i would be ever so gratefull.