#1
So I've got a single channel jcm800 and I just can't roll back the volume or switch pups to get cleans without taking my hand away from strumming. I thought about getting a volume pedal, but they all seem to be not quit what I want. I want something with a preset volume that I can turn on and off, not the angled thing that you press to varying degrees to lower the volume. So I thought of doing this instead:

I'm considering getting some old pedal case, gutting it, sticking in a true bypass switch and a guitar volume pot and connecting them. So when the switch is on, I can just have the pot set to just the right volume to get cleans from the amp without worrying about that angled pedal's gradations and getting it to the right vol with my foot. Essentially, it would be sticking a guitar vol pot, in my pedal chain instead of in the guitar, that I can use as a de-overdrive on/off footswitch.

Would this work? It seems simple enough, but I'm incompetent with this kind of stuff, so I could see there being all kinds of complications that I'm not aware of. Would it need to be grounded and/or shielded? Connected to a power source?
#2
that would work fine, thats a good idea man. it wouldn't need to be shielded, and it just needs to be grounded the same as any other electronics, nothing out of the ordinary. i don't see any reason for a power source either because all it is is a volume pot and a switch. go for it!
#3
Well, you could also get one of those danelectro overdrive or distortion boxes and set the distortion/overdrive to zero and set the level up to where you want it.
It would need a power source, but they only cost $15 - $20 and it would be easy.
#5
Yeah, I have no interest in Danelectro pedals muchless using one like that, it's not like I don't already have an OD. I don't think this guy even read my post.

Thanks, that schematic is helpful. I would use a 500k pot since that's what I've got in my guitars and I'm basically trying to replicate that in pedal form. Funny, I was going to call it the clean machine too...

Would I still use a 100uf cap if it's a 500k pot instead of a 250k one? Why do I even need the cap, I thought those were for tone pots, or am I mixing it up? Is there a reason why the output is stereo and the input is a mono jack?
#6
many volume pedals on the market have an option to set a minimum volume (i.e. as opposed to being no volume when the pedal is fully back you can set the fully back position to be however loud you want. therefore you just rock the pedal the whole way back rather than trying to find the right intermediate spot.)
#7
Quote by Tuckers
many volume pedals on the market have an option to set a minimum volume (i.e. as opposed to being no volume when the pedal is fully back you can set the fully back position to be however loud you want. therefore you just rock the pedal the whole way back rather than trying to find the right intermediate spot.)


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#8
Quote by cutslikedrugsx
Would I still use a 100uf cap if it's a 500k pot instead of a 250k one? Why do I even need the cap, I thought those were for tone pots, or am I mixing it up? Is there a reason why the output is stereo and the input is a mono jack?


The cap is a treble bleed capacitor. It is relatively small and inexpensive and allows your sound to maintain it's treble when the (volume) pot is turned down.
Without this capacitor, your sound will generally lose its high end response as the volume pot is turned down.
Last edited by supergerbil at Apr 15, 2008,
#9
Quote by cutslikedrugsx
Yeah, I have no interest in Danelectro pedals muchless using one like that, it's not like I don't already have an OD. I don't think this guy even read my post.

Thanks, that schematic is helpful. I would use a 500k pot since that's what I've got in my guitars and I'm basically trying to replicate that in pedal form. Funny, I was going to call it the clean machine too...

Would I still use a 100uf cap if it's a 500k pot instead of a 250k one? Why do I even need the cap, I thought those were for tone pots, or am I mixing it up? Is there a reason why the output is stereo and the input is a mono jack?

First of all your instincts are right. When you use this pedal, you'll be adding that pot's resistance in parallel with your guitar. So choosing a value that's the same as what's in your guitar will cause less of a "tone suck" than using a lower value. The resistance of this pot along with the inductance of your pickups forms a low-pass filter. The lower the resistance, the more treble you will lose.

Look carefully at the drawing. The cap is not 100uF (microFarads) It's 100pF (picoFarads) that's one million times smaller. You DON'T need the cap. It's used as a "treble-bleed". It allows a little more treble to get through when the volume is reduced. This compensates for the capacitance in the output cable that works with the pot to make a low-pass filter.

You should build it without the cap, then decide if it sounds a little dull for your taste when the volume is reduced by the pot. If it is, add the cap. 100pF seems a bit small. I would expect something more like 330pF or 500pF to be a better choice. Caps are cheap. Just experiment with different values to find what sounds balanced for the cables you're using and the setting you tend to use most often on the pot.

The stereo input jack is NOT necessary. That particular builder likely uses a template for all his pedal drawings. The box, jacks, and switch are probably the same on all his drawings. A stereo jack is necessary to switch the battery power on when the input cable is plugged in. But since this circuit is passive, you have no battery. A mono jack is all you need.


I hope this helped,
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#10
Ok, thanks. That cleared things up.

Now do I need to ground it or not? The diagram doesn't seem to call for it.

Also, I know I need ceramic disc caps, right? I'm ordering stuff from Small Bear Electronics, and I don't see anything labeled like that. It would be nice if they had pics. What type of wire would be appropriate for connecting everything?