#1
so i got a used, tweaked univibe for 300 bucks last week and i've spent a good few days rewiring it back to its original specs. the original owner had done some nasty rearrangement but luckily left the dual 100k pot that should go in the speed pedal in place of the volume pot. i have swapped out a new volume pot and am now trying to wire the speed control pot inside the univibe (as i have no foot pedal) and just take out one of the instrument jacks but i can't figure out the wiring.

so here's the tech shit: i've got four wires (yelow, green, blue, white) and a naked ground that was hooked to the original foot pedal jack. when i connect the yellow and green through any old pot i can roll it back and forth and sweep through the uni's phase spectrum, but i cannot make it oscillate using the dual pot. i dont know which wire goes out and i dont know which two i should be sending through the two pots...

any help (even a picture of the dual pot inside an original speed control pedal) would be appreciated.

thanks,
marc
#2
Is this a Dunlop Univibe or a real Univox?
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#3
I'm pretty sure in both cases it should be a dual reverse logarithm pot - I don't have any pics of the innards, but I remember the central wiper on both halves being connected to one side of the pot, and that both sides then pass through the same resistor to ground (4.7k probably). With the rev log pot it'll only work properly one way round, and it's generally quicker to test both ways than to work it out - you won't break anything, but the whole sweep will be bunches up at one end if it's wrong. I'm crap at ascii art, so if That Pink Queen doesn't have any info I'll find my univibe copy and draw a schem from it.
#5

Here's a quick drawing of the oscillator in my univibe, which I'm pretty sure is identicle to the stock one. The pot you wanted to put into a pedal has a blue square around it. I included bits like the diodes and transistors since they're easily recognisable (it sounds like you know what you're doing), and you should be able to work out where the traces go. You can see that the wipers are both connected to one side of the pot, which then goes through a resistor to ground. I remember that the knob seems to act in the opposite way you'd expect - if you put it on a panel like a normal knob, it slows down the effect as you turn it clockwise (which is "up" for most effects). That might help you work out which way round to connect it.
Have you got a foot pedal to put this in or are you sticking it on the front panel?
Good luck.
#6
i dont have a foot pedal at the moment but i think it would be pretty easy to get one... i am also considering hooking an external light source and wiring a foot pedal/pot combo as a dimmer so i can control the depth of the vibe instead of the speed of the oscillation. i guess this is as good a chance as any to see what the uni is capable of considering the thing was already molested by the time i came to own it. whee!

thanks for the pic, WS, ill see how it goes and let you know where i get; though i do think you over estimated my capabilities... i have a prett good theoretical understanding of electronics but little experience with diagramming and the like--we'll see though.

marc