I'm quite new to the practical aspects of synthesizers and fx modules (I only just got my first synth a few months ago). As is typical these days, my synth has a variety of onboard effects, but it happens to have no tremolo. Would it work to put a tremolo stompbox between the swell pedal and the synth itself? (i.e., so I'm essentially adding a little LFO to the control voltage coming from the swell).

Why am I not putting the tremolo at the audio output? It appears that most tremolo boxes (or at least the cheap ones) are built for guitars and only have mono 1/4" jacks, but the synth outputs in stereo. (Sure I could pan everything hard left, etc., but I'm looking for a generic solution that won't mess up any future desire to use stereo effects from this synth.)

What's likely to go wrong here given my lack of experience? I'm assuming this will work based on my (limited) knowledge of analog synthesis (i.e., there is no difference between an audio signal and a control voltage), but maybe a tremolo box will be damaged by the CV coming from the swell pedal? Or will it be something more practical like the tremolo depth not scaling with the swell CV (too large for low volumes and too small for large volumes)? Or is a tremolo box not really a simple LFO+VCA, but relies on fancy processing of actual audio signals?

Edit based on the comments:

The synth in question is a hardware synth, a Memotron M2D. Basically a ROMpler controlled by an external midi keyboard. Thus, the only CV-in is a typical 1/4" swell pedal jack. (I guess it's not really a CV-in the sense of modular gear - it's a standard swell pedal input, so the synth must be supplying a CV and the pedal attenuates it? I'm using a Moog EP-3 pedal if that helps.) The onboard effects are just the chorus/flange/echo/reverb variety; no LFO, aftertouch, or other features that can be used for tremolo or vibrato - hence, my somewhat kludge of an approach. I would expect one can use midi CC messages to get the same effect that I'm aiming for, but I've had even more trouble finding midi pedals that do more than just send simple swell, mod, or pitch bend messages.

Note: I feel like an idiot now - there actually is a tremolo effect amongst the onboard effects of the M2D... However, I'm still interested if this idea would work. One could imagine a DIY mod of the pedal so that you have a swell-control tremolo depth (at the moment, there doesn't appear to be a way to change the swell depth and rate via CC control messages...)

  • 1
    It would help to mention the specific hardware you are referring to here; in general though, I would not expect to be able to place a guitar pedal in a part of a circuit carrying CV and for that to work OK (due to possible mismatches in voltage range, impedance, etc and probably more things I'm not thinking of) Feb 3, 2016 at 18:54
  • It would also be interesting to know what the synth is - is there any reason you can't get some amplitude modulation going in the 'synth' part of the synth, rather than using the 'effects' part? Feb 3, 2016 at 18:56
  • What does your VCA CV (swell) look/act like? Is it 1/4" TS or 1/4" TRS? In same cases you can use audio electronics directly on control voltages and vice-versa (that's the basis and magic of modular synthesis!) but in other cases it doesn't work so well. A normal tremolo pedal is designed to process audio, but it may be possible to do what you want. Telling us the exact products in question will help a lot. Feb 3, 2016 at 19:00
  • In addition, it sounds like you might actually just want another LFO in your rig. If you have CV I/O then you should probably look first to leveraging that over other ways to shape sounds when possible. You might want to return the trem pedal and see if you can get an LFO generator instead, although it may cost you more. A Moog CP-251 would be a good tool to have for this. Feb 3, 2016 at 19:03
  • S.Burt - if you need to update your question, that should be fine as you have no answers yet.
    – Doktor Mayhem
    Aug 29, 2016 at 9:12

1 Answer 1


It turns out that in the FX pedal world, a tremolo effect is a stereo-panning effect. It has nothing to do with the definition of tremolo as I understood it (a volume modulation). So my original question doesn't actually make sense given my misunderstanding.

  • I have also learned that tremolo means something completely different in the piano community (rapid playing of two notes an octave apart). I was aware that vibrato and tremolo were often confused, but I was unaware of these other uses of the term tremolo. Do we need a post that clarifies the various (confusing) uses of this term?
    – S. Burt
    Aug 29, 2016 at 16:52
  • I'm not convinced this is true - in the FX pedal world, tremolo is modulation of the volume rather than a stereo pan. You could get a specifically stereo tremolo pedal, but generally, a tremolo pedal for a guitar generally gives rapid modulation of the volume. Think of anything by 'The Shadows'
    – TCassa
    May 9, 2017 at 11:36
  • That was the impression I was under, but the onboard FX of the memotron and the G1xOn multiFX pedal (and it seems like a couple others I looked at) all treat tremolo as a rapid stereo panning effect (which seemed rather bizarre to me). Do you have any specific pedals you can point me to that do volume modulation?
    – S. Burt
    May 10, 2017 at 20:46
  • 1
    To be honest, most stand-alone tremolo pedals on the market work in this way - electro harmonix pulsar springs to mind. As someone who builds a lot of pedals rather than buying them it's a really basic electronic circuit. As a rule, if the pedal you're looking at only has a mono output (and input), it's going to work in this way. A stereo tremolo basically alternately modulates the volume of the left and right channel. If you're looking for something cheap Behringer are good, and there's a lot of good cheap Chinese stuff at the moment like Mooer and Joyo.
    – TCassa
    May 11, 2017 at 8:12

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