DIY Volume Pedals

[Shed_FX]

Hope everyone had a great and productive Christmas! I wasn't able to get out in the shed much due to the cold weather here in England but managed to finish up a couple of projects that thought may be of interest.
This project started out through a desire to have an ernie ball volume pedal but not wanting to pay out £100 for the priviledge!
I found a piece of channel section aluminium in my university scrap bin that I promptly liberated. The basic design is based upon the ernie ball volume pedal and uses the friction drive to move the pot. So here are the fruit of a couple of days labour.



The pot is a 500k Dunlop Hotpotz and I fitted a tuner output on the side to redirect my signal when the pedal mutes.

Most of the work was done by hand apart from a pillar drill for all holes and the brass pulley on the pot was turned on a lathe at university. The beauty of the design is that you can adjust the sweep of the pedal by the diameter of the pulley to give you full turn of the pot. To finish it off I used neoprene rubber for grip.

When I finished, I had enough extra channel section to build another. I decided to  build tone control using an Orange Bass/Treble booster circuit (with an AC128).



This unit has an output level control and the rocker handles the tone. The unit is powered by an external supply as I did not have space to fit a battery inside it. Im pleased with the end results and both can be set and hold their positions. They do take quite a bit of work to do but I enjoyed the break from my soldering iron.

Hope this is of interest and I'll answer any questions or help out if any of you want to give it a go.

Ive just gone down to my local Non - ferrous scrap dealer and bought more aluminium extrusions to make some cases so that can be the next project.

[jakenold]

Great work, Shedmaster.

The downside of moving to an appartment is that I'm now restricted to a 10 square foot room to do all my DIY-stuff, instead of having an entire basement at my fathers house.

Well well, good thing is I can still watch other people do great stuff, with little to no envy at all 

[Barcode80]

GREAT looking Ernie clone! could you enlighten me as to how you set up the circuit to reroute when the pot has the signal muted? that sounds like some circuit magic right there! also, what did you use for the shaft that the pedal pivots on?

[Joe Viau]

A very nice piece of work.

Could you elaborate on the friction drive? Google is not being my friend in this regard.  Is the cable wrapped around the brass pulley elastic? And can I assume that there is a spring of some sort towards the back of the pedal to provide some sort of tension?

Thanks,
Joe

[Shed_FX]

The pedal itself pivots on a 10mm diameter rod of aluminium. The tredle is made using a flat sheet of aluminium with two bearing housings attached. The pivot shaft passes through the base and the bearings and the pedal moves smoothly on the shaft. If you were carefull and got a good fit, you wouldn't need bearings in the joint at all but I did it as I had them laying around.

The tuner output is wired to the live feed that comes into the the pedal. The output signal is then muted when the wiper goes to ground and the signal is then passed through the tuner. The tuner is then connected or disconnected using a SPDT stomp switch to avoid it "tone sucking". Simple really but makes a useful feature. 

Hope this helps

[Shed_FX]

The friction drive is basically a piece of string that passes around brass pulley 450 degrees (one and a quarter times) the string then attached to a spring as in the original Ernie Ball design. Then another length of string attaches from the spring back to the treadle plate behind the pivot.
The design is shown diagrammatically here:

http://edrum.for.free.fr/modules.php?name=Content&pa=showpage&pid=14

I just modified the design from this.

The cord used for the Ernie Ball is a high strength Kevlar line which I couldn't get hold of. I used a multi strand cotton cord which I got from my girlfriend who makes jewellery. The cord is probably about 1mm in diameter and takes a lot of force. Simply the tension from the spring and the friction of the cord on the brass pulley drives the pot around. The string set up in this way holds the pedal where you set it as well.

[calculating_infinity]

Nice work!  I will probably end up buying a ernie ball jr volume pedal because I'm lazy.  Very nice though!

[Barcode80]

shed, if you want the kevlar setup and your dimensions are pretty close to the ernie, you can email them and they will send you a kevlar setup. just tell them your ernie ball "*" pedal broke and you need a new cable. they shipped me one for free within days!

also, check the thread in for sale/trade that i wrote looking for that cable. someone here works at a shop that sells them if you want to go the honesty route

[Shed_FX]

I will see how the cotton cord holds up but may well order an ernie ball kevlar string and then modify it. Thanks for the information tho I will look into it as i may make a few more at some point.

[petemoore]

  I use string from old radio tuner dial movements, good stuff, cotton?...I'd shop more.
  I did something like that using a Vox Shell, but that needed an idler pulley, to direct the string 'back out of the hole, over the case/under the treadle heel.

[Joe Viau]

Thank you very much for the clarification.

[cakeworks]

That's a small piece of genius right there.

I was browsing through auto-one the other day and saw replacement pads for car pedals (look i dont even know if i got the right name there and i dont know what i was doing in auto-one in the first place). but the point is there were things which looked like the footplate from a generic volume pedal.

Has anyone ever used them for diy stuff?

thanks

[Processaurus]

That's a small piece of genius right there.

I was browsing through auto-one the other day and saw replacement pads for car pedals (look i dont even know if i got the right name there and i dont know what i was doing in auto-one in the first place). but the point is there were things which looked like the footplate from a generic volume pedal.

Has anyone ever used them for diy stuff?

thanks

Oh yeah, I've seen car pedal replacements that looked like footprints too.

[Paul Perry (Frostwave)]

The downside of moving to an appartment is that I'm now restricted to a 10 square foot room to do all my DIY-stuff, instead of having an entire basement at my fathers house.

I'm insanely lucky - two rooms & nobody living with me - but I have been very impressed by what I have seen people doing efficiently & reasonably painlessly with very little space. Deep shelves under a table can hold a hell of a lot of stuff (including projects underway), you can get a lot of shallow trays in, think like a baker's oven.
And if you have reasonably high ceilings, run a shelf right across one wall.

But some guys are operating under real difficulties - I saw one chap working with a table that was attached to the door & folded down! like in a caravan. And he had components in pockets attached to the back of the door too.. you get a lot of ideas when you see photos of Moscow life.. bunk beds are one thng, but would you believe bunk DESKS!

[cakeworks]

would it be possible to use a regular pot knob for the pulley and carve the rut with my school's metal lathe?

[Cliff Schecht]

The downside of moving to an appartment is that I'm now restricted to a 10 square foot room to do all my DIY-stuff, instead of having an entire basement at my fathers house.

I'm insanely lucky - two rooms & nobody living with me - but I have been very impressed by what I have seen people doing efficiently & reasonably painlessly with very little space. Deep shelves under a table can hold a hell of a lot of stuff (including projects underway), you can get a lot of shallow trays in, think like a baker's oven.
And if you have reasonably high ceilings, run a shelf right across one wall.

But some guys are operating under real difficulties - I saw one chap working with a table that was attached to the door & folded down! like in a caravan. And he had components in pockets attached to the back of the door too.. you get a lot of ideas when you see photos of Moscow life.. bunk beds are one thng, but would you believe bunk DESKS!

Sounds like you are describing my apartment. I have two roommates so I have to clean up, but the only table I have is the small (4 feet x 4 feet) and I keep all of my components in my closet. I actually managed 3 or 4 builds and quite a few repairs, along with a lot of extensive guitar repair. I completely refinished a 70's Japanese Les Paul clone with a bunch of cool little extras for the circuitry including a custom bracket for a single coil sized humbucker in the neck position at a slant, a pickup split and a preamp. I'm going to be set up to make PCB's in my bathroom and I'm buying a scope within the week probably, so it's going to be getting pretty packed in my room .

[Shed_FX]

would it be possible to use a regular pot knob for the pulley and carve the rut with my school's metal lathe?

If you have access to a school lathe then use a short piece of metal bar. Aluminium or brass work well. If you use a piece about 16mm diameter, 15-20mm long you can cut a groove into that. You will need to experiment with the diameter of the pulley to gain full throw from the pedal but around 13mm should do the job. The pulley can then be secured onto the pot shaft using a M3 grub screw, if you want to do it in a professional way, but a decent adhesive should be adequate. The drawing below shows a side vie of the pulley which should hopefully make more sense.



Using a pot knob could be done but I would have thought it could be difficult to clamp and cut in a lathe. If you were going down that route to save some time and effort I would use an all metal knob like those used on a telecaster or precision bass as these are solid and will put up with the forces that will be applied in the cutting process.

[lookie here]

Ah sweet pedal I was just gonna start a thread about this But i have a question if you dont mind. how would you wire it up?

[Shed_FX]

The tuner output shown here is wired so that my tuner can be connected to the signal line convieniently but this can just be left out. To stop the tuner from sucking any signal away this needs to be disconnected by a switch to break the connection. The switch I have is fitted to the tuner so is not present in the above diagram. The wiring is pretty simple but is passive so you may want to fit a treble bleed capacitor to the circuit to reduce the loss of top end. You should be able to find details on that using the search function.

[petemoore]

You should be able to find details on that using the search function.
  Or just try really small values of caps across the input and output of the box, in this case the circuit and the pot too!
  Say you have a 1meg turned half way, that puts 500k in the signal path, rolling off 'some highs, putting a HF bypass cap across that resistance...BP's HF's, making the pot more evenly attenuate all freq's or, if the cap is a bit larger, bypassing enough HF's so that there is an actual increase in the amount of treble to bass content [treble 'enhancer' I'd say 'booster' but that's a misnomer].
  500k or 250k pot...you might not feel you need the BP cap as much, of course that also lowers impedance to ground.