Does anyone know of a CV expression pedal for modular synth?

[Zooluus]

I recently got a Behringer Neutron semi-modular synth. I'm looking for an expression pedal that I could use to send CV into it's patch bay inputs. I'm not really interested in building something myself.  Anyone know of something I could use?

I found a few pedals but it's unclear if they will work:

Behringer FCV100

DOD FX-17

Mission Engineering 5-CV

[user]

The Behringer pedal specifically states that it will output CV, so it should work, couldn't find the range it puts out in the online specs but I guess you can scale it on the pedal anyway and perhaps use some of the Neutron's utilities for fine-tuning if you wish. I didn't check the others.

[ignatius]

aren't most expression pedals just outputting voltage? you may need an attenuator/offset but you should be able to dial it in. also, i think ADDAC makes a module specifically for this kind of level matching w/o any fuss. 

edit: yeah.. it's actually passive so doesn't need any power. you can just screw to a piece of cardboard. 

https://reverb.com/item/16616959-addac-301b-expression-pedal-passive-eurorack-module

it's probably just an adaptor in there that does the right thing w/the cables to get to 1/8th inch eurorack jacks. but if you get the right cable that goes from 1/4 to 1/8 you should be fine.. are expression pedal cables TRS? if so you might have to make sure you're getting to 1/8 the right way or it could be weird. check modwiggler.com forum i bet a search there will yield results.. though if memory serves the search function there is a bit shitty.. but worth a shot for more info. 

Edited December 18, 2022 by ignatius

[psn]

https://www.moogmusic.com/products/ep-3-expression-pedal-0

[Zooluus]

15 hours ago, user said:

The Behringer pedal specifically states that it will output CV, so it should work, couldn't find the range it puts out in the online specs but I guess you can scale it on the pedal anyway and perhaps use some of the Neutron's utilities for fine-tuning if you wish. I didn't check the others.

It seems to imply that it would send CV and work correctly but any expression pedal you would buy for a non-modular keyboard that has an expression pedal input would also send CV. The difference is that it receives the CV from the synth itself on a TRS cable, then sends back the adjusted CV, based on the pedal position, back to the synth. So it's hard to find a pedal that actually generates it's own CV and outputs enough to control the full sweep of a parameter.

7 hours ago, psn said:

https://www.moogmusic.com/products/ep-3-expression-pedal-0

Found that one too, but it's a passive expression pedal. It sends CV, but it first receives the CV from the synth itself.

[Zooluus]

15 hours ago, ignatius said:

aren't most expression pedals just outputting voltage? you may need an attenuator/offset but you should be able to dial it in. also, i think ADDAC makes a module specifically for this kind of level matching w/o any fuss. 

edit: yeah.. it's actually passive so doesn't need any power. you can just screw to a piece of cardboard. 

https://reverb.com/item/16616959-addac-301b-expression-pedal-passive-eurorack-module

it's probably just an adaptor in there that does the right thing w/the cables to get to 1/8th inch eurorack jacks. but if you get the right cable that goes from 1/4 to 1/8 you should be fine.. are expression pedal cables TRS? if so you might have to make sure you're getting to 1/8 the right way or it could be weird. check modwiggler.com forum i bet a search there will yield results.. though if memory serves the search function there is a bit shitty.. but worth a shot for more info. 

I'm not sure if that would work, unless it was with a powered expression pedal that sends CV on it's own. The CV has to come from somewhere and almost every pedal I find is getting that power supplied from the instrument. I was thinking about getting a module I've seen that is powered and generates a CV, sends it through TRS to passive pedal then back to module. But with the price of the module + power I would need to run the module, makes it not really worth it.

The Mission Engineering 5-CV seems to be the only one that states what voltage it sends (0-5v). But the Neutron CV IN's are expecting -5v to +5v so I'm not really sure if that means it will work or not.

Edited December 18, 2022 by Zooluus

[psn]

1 hour ago, Zooluus said:

Found that one too, but it's a passive expression pedal. It sends CV, but it first receives the CV from the synth itself.

A voltage source module and an insert Y cable will probably get you there. 

Edit: like you said. 

Edited December 18, 2022 by psn

[user]

1 hour ago, Zooluus said:

It seems to imply that it would send CV and work correctly but any expression pedal you would buy for a non-modular keyboard that has an expression pedal input would also send CV. The difference is that it receives the CV from the synth itself on a TRS cable, then sends back the adjusted CV, based on the pedal position, back to the synth. So it's hard to find a pedal that actually generates it's own CV and outputs enough to control the full sweep of a parameter.

Found that one too, but it's a passive expression pedal. It sends CV, but it first receives the CV from the synth itself.

Yeah, which is described in the blurb on the website as the difference between the "norm" and "other" output. IE the norm output scales whatever is being put through the pedal and the "other" output is a CV generated from the pedal. Hence the 12v psu that is needed.

In the long run a scaling pedal is going to be more interesting IMHO. Unless you have incredibly floppy shins you're gonna get some pretty static modulation from a cv pedal and it's going to be way more interesting to send a lfo or sequence through it and scale it with a foot. IMHO

You make a good point re; the difficulty finding a pedal that will put out the 20 volts peak to peak range that might be encountered in eurorack. And even if you did you'd probably want scaling because there's only so much travel on any given pedal.

Edited December 18, 2022 by user

[Zooluus]

2 hours ago, user said:

Yeah, which is described in the blurb on the website as the difference between the "norm" and "other" output. IE the norm output scales whatever is being put through the pedal and the "other" output is a CV generated from the pedal. Hence the 12v psu that is needed.

I wish you were right cause then I'd have my solution. But from what I read in a modwiggler discussion, it's not the case. Very misleading on Behringer's part. Quote from Behringer regarding the pedal:

Quote

I have spoken to a colleague of mine who has more experience with the FCV100 and apologies but I was incorrect about it's operation. The FCV does not generate a control voltage it is just a volume controller or expression pedal.
In Normal mode:
input 1 (tip) -> Active VCA (volume control) -> output 1 (tip)
input 2 (tip) -> Active VCA (volume control) -> output 2 (tip)
sleeve on both is grounded.
In CV mode:
output 2 (tip) -> Passive 50kOhm pot (volume control) -> output 2 (sleeve)
in 1 and out 1 are the same.
In all circumstances there is no voltage on any of the inputs/outputs.

2 hours ago, user said:

In the long run a scaling pedal is going to be more interesting IMHO. Unless you have incredibly floppy shins you're gonna get some pretty static modulation from a cv pedal and it's going to be way more interesting to send a lfo or sequence through it and scale it with a foot. IMHO

What exactly do you mean by this?

[user]

2 hours ago, Zooluus said:

I wish you were right cause then I'd have my solution. But from what I read in a modwiggler discussion, it's not the case. Very misleading on Behringer's part. Quote from Behringer regarding the pedal:

What exactly do you mean by this?

Very nicely obliquely marketed by behringer then.

What I meant was that I would probably prefer to use an expression pedal as a passive attenuator to control the intensity of, say an lfo rather than have the pedal generate a voltage. And because the operating ranges of CV inputs vary wildly (i.e. one input will operate from -3 to +5 volts and another from 0 to +10 volts) you'd probably want to have some offset and scaling controls and then when you've dialed those in you can finally attenuate the signal with the expression pedal. If the pedal would be the source of the voltage it would either be very limited in its use or it would have to have on-board scaling and offset controls. I mean, it boils down to the same thing more or less but it just makes more sense to do this elsewhere than on the expression pedal.

I think you'd still be fine using this with the neutron, IIRC one of the attenuators can be used as a 5V voltage source when you use a dummy cable on its input and then turn up the control, then you can patch that out to the expression pedal.

 

 

 

[TubularCorporation]

DOD FX-17 volume/wah can also work as a CV source.  Old, but really solid and space efficient.

 

[Zooluus]

20 hours ago, user said:

Very nicely obliquely marketed by behringer then.

What I meant was that I would probably prefer to use an expression pedal as a passive attenuator to control the intensity of, say an lfo rather than have the pedal generate a voltage. And because the operating ranges of CV inputs vary wildly (i.e. one input will operate from -3 to +5 volts and another from 0 to +10 volts) you'd probably want to have some offset and scaling controls and then when you've dialed those in you can finally attenuate the signal with the expression pedal. If the pedal would be the source of the voltage it would either be very limited in its use or it would have to have on-board scaling and offset controls. I mean, it boils down to the same thing more or less but it just makes more sense to do this elsewhere than on the expression pedal.

I think you'd still be fine using this with the neutron, IIRC one of the attenuators can be used as a 5V voltage source when you use a dummy cable on its input and then turn up the control, then you can patch that out to the expression pedal.

 

 

 

Oh ok, yeah i see your point. I mainly want it cause i'm running my guitar thru the synth. Was hoping to replace my filter/wah pedal for the guitar and just use the synth's filters. It's cool now with the LFOs in the mix but I'd still like an expression pedal sometimes. But yeah, if I wasn't doing that, I probably wouldn't find much use for the expression pedal.

[Zooluus]

11 hours ago, TubularCorporation said:

DOD FX-17 volume/wah can also work as a CV source.  Old, but really solid and space efficient.

 

Yeah, I might try it.

Edited December 20, 2022 by Zooluus

[TubularCorporation]

Honestly, if you aren't going to use the wah or volume part of it I'd go with the Behringer, they're perfectly decent quality and work well.

 

EDIT: NM I misremembered, the weird EHX accelerometer-based Next Step pedals don't actually have expression output.  Also they're kind of awful to use even though they're really well made and sensitive.

Edited December 20, 2022 by TubularCorporation