Volume.

[Snoo]

Hi.

Has anyone a circuit layout for a volume pedal?

I've ripped the guts out of an old wah-wah with a view to using that. I put in a basic pot to try first but that doesn't seem to work.  :?:

Can anybody help me out?

Cheers,
Snoo.

[Peter Snowberg]

Welcome Snoo,

This is how to wire a "passive volume pedal".

The pot has three "lugs"... we'll call them #1, #2, and #3, with #2 being the one in the center. I don't know what direction your pot rotates, so you might have to swap the wires on #1 and #3. It will work, but the travel might be reversed.

Start by connecting the ground connections of the in and out jacks together and then connect them to lug #1.

Connect the tip connection from the input jack to lug #3, and finally connect tip of the output jack to lug #2.

There you go. Good luck with it!

Take care,
-Peter

[Snoo]

Thanks for that Pete.

All the best.

Snoo.

[Triffid]

Any Ideas as to what type of pot to use... normal wah pot?  how many ohms?

Thanks

[Snoo]

I can't remember off the top of my head but I believe it can depend on the type of pick-up the guitar uses.

That might just be with active pedals though.


As long as it's a linear I guess any decent pot of 100k should do. Though I could be wrong.

[smoguzbenjamin]

Wrong, snoo! Hearing is logarithmic. A sound has to get 10 times louder for it to sound twice as loud. Therefore, a log pot will "feel" much better 100k is a good value.

[petemoore]

Sometimes to get a volume to work 'just' the way you want it...
 Starting with a large value pot, I put a resistor across the 1&3 lugs to bring it down to a lower value experiment to taste a 100k ficed R in this position across a 100k pot makes it effectively a 50 pot ...also
 You can adjust the taper in a similar way by adding resistors to the 1&2 lugs or the 2&3 lugs...I get the efkt going through an amp, then 'wrap' the different resistor values I want to try on the lugs till I find the action I want.
 You can also add resistors to where Lug goes and lug one [outside the pot] same for lug three and where it goes...but these of course muct be 'spliced' in the line.

[Arn C.]

I have heard that you can use the same value pot that is in your guitar (volume pot)  I have some guitars with 250K, 500K and one with 1 Meg, they are all log taper not linear.
Peace!
Arn

[Mark Hammer]

The value of the pot will depend on where you locate it in the signal chain.  This is to provide a reasonable compromise between the output impedance of the device before the volume pedal and the device after it.

If you position it between an effect pedal and the amp, then you won't lose much high end with a 100k pot.  If you plan to use it between the guitar and a pedal or between the guitar and the amp, then a higher value pot will be helpful in retaining top end for that upper 3rd or so of the pot's rotation.  There, I'd suggest pot values that compare more with what you'd use for your guitar.  So, values of 250k to 1meg are not unreasonable.

If you do some quick reading on guitar volume controls, you will see that higher value pots are recommended for retaining more treble (or rather not losing as much), and lower-value ones are recommended for constructively shaving off a bit of "brittle" high end.  Typically, people use 500k volume pots for Gibson-style humbuckers, and 250k-500k pots for Fender-style single-coils.  The lower value pots for Fenders result in loss of a little bit of the extra high end single-coils provide, in order to "warm up" the tone of the pickups.

All of that is in anticipation of what will happen to the tone when a guitar pickup of a given impedance is plugged into an amp of a given input impedance, over a cable of a given cable capacitance and length.  I wouldn't go so far as to say that all bets are off when the volume pedal is placed between two effects or between the last effect and your amp, or in the amp's effect loop, but it does make the requirements for pot value less critical, and 100k can and will work fine.

Volume pedals are certainly simpler if they are passive, but depending on how you use them, passive can have some drawbacks, not the least of which is noise and crackle when the volume pot is moved.  If you're a set-and-forget guy then a normal passive arrangement can work more than acceptably for years on end.  If you are a more active user of a volume pedal for swells, foot-produced tremoloes, and pedal-steel effects, then the risk of pot-related noise starts to be of concern.  Here, folks tend to prefer active volume pedals than can involve either voltage control (e.g., the Craig Anderton Volume Pedal Retrofit, which first appeared in Guitar Player around 1980, and can be foundin clone form at www.tonepad.com), or some sort of optical control, like the Goodrich or Morley pedals. These types of designs use the pot for controlling something else that in turn controls volume.  By having the footpedal one or two steps removed from the actual volume adjusting element, there is an opportunity to intervene and eliminate the risk of pot scratchiness being heard.  The pot will certainly suffer the same use/age-related decline as a passive pedal, but you won't hear it.

[smoguzbenjamin]

I have a passive volume pedal, and I use it for swells all the time. Sounds fine to me and I've had this pedal for almost 8 months now.

[Mark Hammer]

Yeah, nothing wrong with them.  It's not the first 8 months I'm cautioning about.  It's when they're 3 years and 8 months.

[smoguzbenjamin]

I don't mind paying $4 for a new pot every 3 and a half years.

[Mark Hammer]

Actually, I was just about to add on that when you consider what it DOESN'T cost in batteries for the same lifespan, that more than offsets the cost of buying even a topnotch pot every 3-4 years.

....but you beat me to it.  :lol:

[smoguzbenjamin]

Well, batteries ain't the problem, I'm a wallwart person and I use a daisy-chain. However I have to do something about ground loops once I finally start adding my own pedals to that. But that's a different topic