Volume Pedal Sucky Poobum :(

[Cdog]

I bought a Modtone Volume pedal... works ok, taper is nice enough, only problem is... it aint true bypass like they claim. There is a noticeable (to my reasonably fussy ears) tone suck from the circuit, and that kinda ticks me off I guess all Volume pedals must load down the guitar unless they are switched, but this one had two pots... the big inductor style one and a 'range' pot which sets minimum volume level.

So how hard can it be to make it true bypass? here's the original schem:



Then I thought, what about using it as a expression pedal as well... So my idea is using a 4PDT mounted under the toe in the normal spot:
Position 1 is guitar signal true bypassed, Volume pot routed to AUX jack for expression control, and Green LED indicator
Position 2 is guitar signal through volume pot, aux jack bypassed, Red LED indicator

Here's what I came up with:



Will this work? Kinda new to drawing schematics so I hope it makes sense... (I note the LEDs are the wrong way round)
I'm not too sure about expression pedals to be honest either, haven't got a use for one yet, but would like to try it out... the pot is 250K, will that even work???
Your comments would be welcome

[Ironbird13]

re the expression pedal, no idea if your schematic is correct, but you may have to swap polarity depending what you are using it with, my M-Audio exp pedal i use with the HOG has a switch to change it

[pete_currie]

Another way to fix the problem is to build and install a basic buffer.
Stick it straight after the input jack.
Then the volume pedal can be in your chain all the time without any tone suck.
Just a suggestion

[Cdog]

re the expression pedal, no idea if your schematic is correct, but you may have to swap polarity depending what you are using it with, my M-Audio exp pedal i use with the HOG has a switch to change it

Does it have a dedicated expression output? Do you know what value the pot in you pedal is? 250K? 25K?

Another way to fix the problem is to build and install a basic buffer.
Stick it straight after the input jack.
Then the volume pedal can be in your chain all the time without any tone suck.
Just a suggestion

Thanks Pete. Yeah I tried putting a buffered pedal before the volume in the chain, and even a boost pedal on low volume... it improves things but still sucks tone. Maybe I should just start by disconnecting that 2nd pot in it... I have no idea what value it is but that might help

[MogwaiBoy]

One thing about the Ernie Ball volume pedals etc (and may relate to this one aswell) is the Tuner Out jack. If you are using it (the tuner out jack to a tuner) then the pedal splits the signal and messes with the impedence or something - hence loss of high end, AKA "tonesuck". So first things first, don't put your tuner in the tuner out!

Kinda interested in this pedal too myself...

[Cdog]

One thing about the Ernie Ball volume pedals etc (and may relate to this one aswell) is the Tuner Out jack. If you are using it (the tuner out jack to a tuner) then the pedal splits the signal and messes with the impedence or something - hence loss of high end, AKA "tonesuck". So first things first, don't put your tuner in the tuner out!

Kinda interested in this pedal too myself...

Yes that could cause an issue, I experimented a lot to make sure it wasn't leads or anything either...

So I bypassed the 2nd 'Range' pot... it was a 100KB. Definite improvement in the overall tone suck, and with a buffered pedal in front now it sounds ok, but still a little sucked. Prolly enough to satisfy me tbh... certainly easier than a refit for now. Still interested in trying my mod, I'll just need to get the switch first. Any comment son tweaking vol pedals or expression pedals still welcome

[Ironbird13]

Does it have a dedicated expression output? Do you know what value the pot in you pedal is? 250K? 25K?

it IS a dedicated expression pedal and no idea on the pot in it, but its one of these...http://www.m-audio.com/products/en_us/EXP.html

[druz15]

maybe not the best expert but looking at the schem you've drawn up it looks pretty good Corey. Maybe some tweaking needed to get it working well but it looks like it should theoretically work

[twistedthoughts]

If you want to try a Boss FV500L, flick me a PM.

[Cdog]

If you want to try a Boss FV500L, flick me a PM.

Thanks man.

Looking into the technicals, the only way to do a duo pedal is have two pots Expression pedals are mostly 10K and require quite different wiring to volume pedals. As a side note I tweaked the Volume pot in the pedal... on toe down it was still 80k Reisitance, which explains the tonekill... I tweaked to position of the pot it so that on toe down resistance is 300 R, almost nothing... so no tone suck, downside is it doesn't quite kill the whole signal on heel down now but I never used it for that anyway...

[druz15]

If you want to try a Boss FV500L, flick me a PM.

Thanks man.

Looking into the technicals, the only way to do a duo pedal is have two pots Expression pedals are mostly 10K and require quite different wiring to volume pedals. As a side note I tweaked the Volume pot in the pedal... on toe down it was still 80k Reisitance, which explains the tonekill... I tweaked to position of the pot it so that on toe down resistance is 300 R, almost nothing... so no tone suck, downside is it doesn't quite kill the whole signal on heel down now but I never used it for that anyway...

would a smaller pot fix this issue? or is it the sweep isn't big enough? maybe a resistor wired in series so that with heel fully down it's off. I would hate having a volume pedal and not being able to do swells, but then again I don't have a volume pedal

[Cdog]

The sweep is awesome, its just it can't mute the guitar now... so it goes from full noise to almost mute... at the extreme heel down position there is faint guitar sound still coming through. Its more important to me to have pristine 'bypass' tone than a mute function