Members loosegroove Posted August 21, 2008 Members Share Posted August 21, 2008 I need a speed control pedal for an original Shinei Univibe. Will the current Dunlop one work if I use a 1/4 Stereo-XLR male cable? Link to comment Share on other sites More sharing options...
Members loosegroove Posted August 21, 2008 Author Members Share Posted August 21, 2008 Doh, just realized it's a multi pin jack that is definitely NOT an XLR. So any help? Since it seems like the Dunlop won't work, can I easily make one or can someone make me one? Link to comment Share on other sites More sharing options...
Members Let It Burn... Posted August 21, 2008 Members Share Posted August 21, 2008 pics of the jack? Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted August 21, 2008 Members Share Posted August 21, 2008 The jack is a 5-pin DIN, just like a MIDI jack. You can get plugs for those just about everywhere. The pedal itself contains a dual-gang log taper pot that's mounted in such a way that it turns counter clockwise when you push down on the toe. This is the opposite of the way that the pot is mounted in most other controller pedals. There's also a microswitch in the heel that kills the LFO when you press the heel all the way down. There's no way that the Dunlop UV-1FC pedal has a dual-gang pot in the same configuration as the original Uni-Vibe controller pedal - not if it's only got a TRS jack. The original pedal used all five pins on the DIN jack; three for the pots, and two for the cancel switch. I've seen people make hand controllers for the original Uni-Vibe. You just need a dual-gang (e.g., "stereo") audio taper pot. If you wire it up correctly then the speed will increase as you turn the pot counterclockwise. I know this seems bizarre, but if you wire the pot backwards so that the speed increases when you turn it clockwise then all of the speed change is going to be crammed into the last few degrees of rotation. You could solve this if you could find a dual-gang anti-log pot. That's a pretty big "if", though. Link to comment Share on other sites More sharing options...
Members loosegroove Posted August 21, 2008 Author Members Share Posted August 21, 2008 Yeah, it is a standard Midi 5 pin style jack :poke:...I was posting without the pedal in front of me but I still don't understand how I didn't realize that . I don't know crap about electronics but the whole counter clockwise thing makes sense if you consider the configuration of most wah/expression pedals. The pot is often turned counterclockwise in the toe position so that would work. So how do I go about making one of these? I just need to get a midi cable, dual gang stereo pot, and a momentary switch? How do I wire it up? And would it be easy to change that momentary switch to a latching switch instead? Then I'd need a donor wah or volume pedal that allowed me to remove the gear from the shaft of the pot so I could use it on the new one. Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted August 21, 2008 Members Share Posted August 21, 2008 So how do I go about making one of these? I just need to get a midi cable, dual gang stereo pot, and a momentary switch? How do I wire it up? And would it be easy to change that momentary switch to a latching switch instead? Then I'd need a donor wah or volume pedal that allowed me to remove the gear from the shaft of the pot so I could use it on the new one. The schematics that are all over the internet, including at Schematic Heaven, show a pair of 250K pots, but the pots in my pedal are 100K. I've also seen articles on the internet that describe 100K pots, including the "Technology of the Univibe" article by R.G. Keene. Not a surprise - there are several mistakes on that schematic. A 100K dual-gang audio taper pot should work. BTW, I checked Small Bear and they DO sell a reverse audio taper pot, dual-gang 100K, specifically for making hand operated speed controllers for Univibes. Anyway, I digress... You may have to mill out the hole in the top of the base casting in order to get the dual-gang pot to fit. Once you've done that, mount the pot so that the solder lugs are facing the bottom; i.e., you can easily get to them from the bottom of the pedal. You're going to need a five wire cable and a 5-pin male DIN plug. The cable doesn't need to be shielded as no audio goes through it. 1. Bend the center lug on the outer pot (the one farthest from the shaft) upward and solder it to the center lug on the inner pot (the one closest to the shaft). Solder a wire to these two lugs. Connect the other end of the wire to pin 1 on the DIN plug. This is the blue wire in the picture. Pay close attention to the pin numbers on the DIN plugs - they are NOT numbered in sequence. 2. Solder a wire to the lug on the inner pot which is farthest from the toe. Connect the other end of the wire to pin 4 on the DIN plug. This is the yellow wire in the picture. 3. Solder a wire to the lug on the outer pot which is farthest from the toe. Connect the other end of the wire to pin 2 on the DIN plug. This is the black wire in the picture. 4. Connect pins 3 and 5 on the DIN plug to the cancel switch. These are the red and white wires in the picture. For the cancel switch, I wouldn't use the switch that's already in the wah pedal. You'd have to roll the LFO speed to max (toe down) before you could turn off the LFO. If you want it to work just like the original Univibe pedal then you'd need to mount a switch at the heel of the base casting. A pushbutton momentary contact switch would probably work. Get one with a short stroke, and drill a mounting hole in the top of the base casting close to one corner of the heel so that the treadle will hit it when the heel is down. You could use a latching switch, but there's not much point if the treadle doesn't do anything when the switch is off. If you decided to use a fuzz-wah chassis then you could just use the fuzz switch to turn the LFO on and off. That way you wouldn't have to move the treadle. There aren't too many places to mount a separate switch on a regular wah chassis. I suppose if you really want to get crazy you could mount a latching switch right on the treadle at the heel! Then you could just stomp your heel on the heel of the treadle to turn off the LFO. Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted August 21, 2008 Members Share Posted August 21, 2008 One more thing... You could rape a MIDI cable for the plug, but you probably couldn't use the cable itself. Most MIDI cables have two wires plus a shield. You need a five wire cable. Link to comment Share on other sites More sharing options...
Members loosegroove Posted August 21, 2008 Author Members Share Posted August 21, 2008 Awesome. thanks man! This is one of those things that should be easy enough for me to do, but due to my crappy soldering skills and lack of motivation, it will take me forever to get around to doing. Link to comment Share on other sites More sharing options...
Members ruexperienced Posted March 15, 2011 Members Share Posted March 15, 2011 A 100K dual-gang audio taper pot should work. Help! Thanks a lot for this info. I have an original Shin-ei Uni-vibe without the foot controller but bought a Shin-ei wah with same foot case as my other Shin-ei Uni-vibe that does have the foot controller. I have the 5 pin cable that came with the hand controller (Small Bear type) and the original cancel switch but can't find the 100kB dual gang reverse log taper pot. So you're saying that if I get a dual stereo log taper 100k pot and wire it like you have above, then it will work and the speed will increase with toe to floor? Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted March 16, 2011 Members Share Posted March 16, 2011 Help! Thanks a lot for this info. I have an original Shin-ei Uni-vibe without the foot controller but bought a Shin-ei wah with same foot case as my other Shin-ei Uni-vibe that does have the foot controller. I have the 5 pin cable that came with the hand controller (Small Bear type) and the original cancel switch but can't find the 100kB dual gang reverse log taper pot. So you're saying that if I get a dual stereo log taper 100k pot and wire it like you have above, then it will work and the speed will increase with toe to floor? Yeah. The reverse log pot is only needed if you want to make a hand controller that increases the LFO speed at more or less the same linearity as the foot controller. If you're mounting the pot in a pedal, and the pedal rotates the pot as shown in the pics above, then a regular 100K dual gang audio taper pot will work fine. Link to comment Share on other sites More sharing options...
Members ruexperienced Posted March 16, 2011 Members Share Posted March 16, 2011 Hey thanks a bunch. I just hope I don't fry my 40 year old Uni-Vibe if it isn't right. I bought this one today I'm just curious though as to why Shin-ei chose a B100k reverse log taper pot instead of the one you suggest. http://www.radioshack.com/product/index.jsp?productId=2062359 Problem with this one is the shell is kind of like a mini shell but the shaft seems normal size and may be long enough for the treadle to work. Think it will? Link to comment Share on other sites More sharing options...
Members loosegroove Posted March 16, 2011 Author Members Share Posted March 16, 2011 Awesome, thanks for the thread bump from years back. Maybe I'll finally build me a speed control pedal now...I've already procrastinated 2 and a half years! Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted March 16, 2011 Members Share Posted March 16, 2011 Hey thanks a bunch. I just hope I don't fry my 40 year old Uni-Vibe if it isn't right. I bought this one today I'm just curious though as to why Shin-ei chose a B100k reverse log taper pot instead of the one you suggest. http://www.radioshack.com/product/index.jsp?productId=2062359Problem with this one is the shell is kind of like a mini shell but the shaft seems normal size and may be long enough for the treadle to work. Think it will? If the bushing fits then it ought to work. There's not much chance you could fry anything. However, you wouldn't want to inadvertently inject the wrong voltage anywhere, especially on pin 5. That pin is connected to the base of the lamp driver transistor. Blowing out either the transistor or the lamp would not be good. They chose that pot because the frequency of the LFO doesn't change in linear proportion to the value of the resistance. A non-linear pot was needed to get something resembling a linear speed control. I made a schematic that accurately reflects my old Shin-ei Uni-Vibe. Shoot me another email if you want a copy of it. Link to comment Share on other sites More sharing options...
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