In this third edition of our tech corner series, I’ll explain a simple and easy way to use a volume pedal as an expression pedal. This cool little trick was shared with us by our good friend Chad. This article will be the last on expression pedals specifically, although there are many other interesting diy projects we can do in the future with the EXP input on Strymon gear.
If you’ve got a volume pedal hanging around that doesn’t get much use or better yet one already on your board, you can use it as an expression pedal with one special cable. It’s called a TRS (tip/ring/sleeve) insert cable and the purpose of this cable is normally to break out a TRS insert jack (commonly found in mixers) to the separate send and return signals. Luckily we can take advantage of this wiring to convert our volume pedal into a standard 1/4″ TRS equipped expression pedal.
One example of this type of insert cable is the Hosa STP-201 seen below.
Once you have a TRS insert cable, simply plug the TRS plug into your exp input, the “ring” plug into the volume pedal input, and the “tip” plug into the volume pedal output. That’s all there is to it! Now you can use volume pedals like the popular Ernie Ball VP Jr or the new Dunlop DVP-1 as expression pedals for your Strymon gear and most other gear featuring expression pedal control. What is actually going on here is that we’re taking advantage of the design of a passive volume pedal and re-wiring it as an expression pedal with this cable. Note that your volume pedal needs to be passive, not active and the impedance (value of the resistance) in the volume pedal’s potentiometer isn’t critical. One thing that may be a little bit different about using the volume pedal as an expression is that if the volume pedal uses an audio taper potentiometer you won’t get a linear sweep of expression pedal values from toe to heel. In other words, much of the action will happen at one extreme of the pedal.
As you can see, the expression pedal schematic from Tech Corner #1
is functionally identical to using a volume pedal with a TRS insert cable.
Here is a video walk-through:
Hopefully this has been a useful trick to get you rocking that expression pedal.
Happy shredding,
Terry
Tags: diy, electrical engineering, expression pedal, how to, pedal, tech corner, timeline, TRS cable, volume pedal
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Wow. So that means that I could theoretically use a Morley PWB, which has the longest physical sweep of any pedal I have ever used, as an expression pedal. That would be spectacular, especially with the Lex.
Remember, it has to be a passive volume pedal. The Morley is active.
Wow, sweet! Oh, and, nice boots.
Yeah ok, not to be distracted, but what kind of boots are those?
Would this work if I was using the expression pedal to control a 5k pot on a pedal? I had the pedal modded so that a certain knob is able to be expression controlable.
Can I use this tip on El Cap?
Definitely! This will work for El Capistan, Brigadier, Orbit, Lex and TimeLine.
Does Strymon sell this TRS cable? If so how much?
Hi Joshua, no we don’t sell it but it’s readily available online. Thanks for reading :)
Thanks so much Terry! Man, ya’ll’s customer service is great! And fast! :)
Hello!,
Is there a way to have an expression pedal and a toggle pedal at the same time into the Timeline? Would love to do this expression trick and to also send tap tempo control into a separate external pedal because I feel like i could break the timeline by tapping it so much.
Thank u!
Hey there! No need to worry about breaking the switch, that’s what it’s there for! The expression pedal input will only do one thing at a time, so you’d need to choose either external tap or expression. Though you could use a midi controller to control your tap if you like. Hope this helps. :)
I’would to buy an Ernie ball VP…it’s the same 250k or 25k?
Either should work with this trick.
Could you use an expression pedal to control the volume of a loop going? I have a midi controller that I use to trigger the looper
Hello,
this is very interesting,
but how to lower the 250K to 50K to suit the needs of an AXE FX for exemple (AXE FX accepts from 10K to 100K, but 250K is probably too much
Hi lowering the resistance of the pot is a bit difficult without completely ruining the taper, however i would imagine the AxeFx will actually accept the 250k definately worth a try. if it doesnt work the easiest thing would be to just change the pot. also there is no impedance in a resisitive circuit as it is suggested above. Impedance is a re-active measurement and requires a cap or inductor of some sort in the circiut.
Hi:
I’m sure others may have tried this….but if not IT WORKS GREAT FOR ME.
I have multiple Strymon pedals as well as pedals that work with an Ernie ball VP Jr as an expression controller.
In addition to the Hosa STP-201/202.
I added a HOSA YPP-308 cable … (Stereo 1/4″ Female to 2 Stereo 1/4″ Male Y-Cable)
Which means I can use one Volume pedal to control 2 effects instead of a controller for each effect….it’s a little too late to worry about saving space on my board , but this helps a little. :)
I am very pleased to know this as I prefer the Ernie Ball VP Jr to all the other pedals out there. One question: does the Hosa STP-201 come in shorter lengths?
[...] interesante viene al investigar un poco y ver en el blog de strymon esta entrada sobre transformar un pedal de volumen en uno de expresión. En el esquema se aprecia que el pedal [...]
Hi Terry!
Expression Ernie Ball VP JR 25k works with the timeline?
Thanks!
[...] This is a pretty cool idea: Strymon Tech Corner #3 [...]
I just tried it with Boss FV-60 and my Hammond XK-1. I got almost the full range (about 30-127 which is plenty for the Hammond) in the pedal Monitor page on the Hammond (nice feature). So I am going to brush up on my basic electronics schematic reading and modify the pedal to use TRS connectors on a single cable. And the nice thing about it is that it’s a stereo pedal- it has a dual pot so I can make it a double CV pedal- just because I can! This will work well enough for rehearsals.