EV-5 pedal & voltage control

[Paul Perry (Frostwave)]

http://www.worldofschmitt.com/projects/roland_ev5/ev-5-schematics.html
has a schematic of the EV-5. I havn't got an EV-5 - they are ungodly xpen$ive, especially for something made of thin plastic...

From the schematic, it looks like whatever it plugs into, supplies voltage to the ring of a tip/ring/sleeve (stereo type) plug, & the foot operated pot then picks off some voltage & feeds it back via the tip.
What I would like to know, is whether all Roland/Boss stuff that uses the EV-5, operates on the same voltage, and whether I can just run a variable control voltage to the tip of a stereo cable going to the Roland gear?? Because if so, it wd be possible to control those Boss fx by a MIDI to CV converter, for example, or some homebrew envelope follower etc.

Is the moog expre$$ion pedal the same?? or the same, but without the series trimpot??

[Processaurus]

Hi Paul, I measured my PS-5 super shifter expression pedal input, and the ring measured 3.35v.  I measured from the tip to ground too, and that was 3.27v.  Don't know the story there.  I've tried hooking stuff like lfos from a synth up to it a while ago, and it worked alright.  It would be neat to have a theremin controlling the pitch, so you could thereminize anything.  A kind of whammy theremin.

[Paul Perry (Frostwave)]

thanks Processaurus (great name!!!).
If you happen to have a stereo lead, could you plug it into the PS-5 and see what it says (unless that is what you did already!!).

Even better, if you or some other kind person has a stereo Y cable or stereo Y splitter socket & can look at what happens on teh tip & ring as the pedal moves... we can't let Boss go on getting away with $$$ for these controllers :wink:

[peter ripa]

yes youre right. the ev5 is just a resistor, same as the ev7 ( which is alot bigger and not so flimsy and whith nice sweep range) and the moogerfooger ep-1.
its supposed to go from 0-5 v but IME its slightly less. controlling such units with another voltage is possible, at least i do it all the time
the line6 expression inputs didnt work and i didnt bother to check its specs, supposedly its not "boss compatible".
using the moog cp251 which has a cv junction that sends voltage on one of its sockets its also possible to control units that otherwise would require an active cv pedal ie the ms20. ev7 in the sockets that sends and then a regular mono cable into whatever you want to control.
/peter




What I would like to know, is whether all Roland/Boss stuff that uses the EV-5, operates on the same voltage, and whether I can just run a variable control voltage to the tip of a stereo cable going to the Roland gear?? Because if so, it wd be possible to control those Boss fx by a MIDI to CV converter, for example, or some homebrew envelope follower etc.

[Processaurus]

Paul, I had a chance to check out more on the ps-5 expression pedal input (it got left out at our practice space/garage for a couple days).  I don't actually own an EV-5, so I just hooked up a 10k linear pot to a TRS jack plugged into the expression jack, like the ev-5 is wired.  With the load of the pot, the voltage on the ring was down to 3.0 volts.  The tip (connected to the wiper) acted as a regular old voltage divider, going between 0-3 volts.

Here's an idea- if different boss pedals (or other gear using expression pedals with a similar system) use different voltages you could make a universal controller by taking the voltage the device puts on the ring and route that to a VCA (setup to go between zero and unity gain), and the output of the VCA goes to the tip.  

Good luck with your project, I'm sure there's a market for it.  People have got to be frustrated spending $50 on a plastic P.O.S. like the ev-5

[Paul Perry (Frostwave)]

That's a good thought Processaurus!
Now I'm wonderign about what the Line 6 stuff uses...

[puretube]

http://diystompboxes.com/sboxforum/viewtopic.php?t=33554&highlight=line6+expression