Retro fit Volume Pedal - tonepad

[Ubertech_s]

HI All

One of the last elements for my homemade board is a Volume pedal. I found this board on tonepad, but its described as retro fit, so I dont know if Im supposed to add it to an existing vol pedal, or if I just need the hardware and this is complete.

PLease can some one transcribe it to vero.

here's the description of the theory behind Craig Anderton's vol circuit: "the circuit [that is in the link] solves several problems. Number one it eliminates scratchy pots as its just used to divide a voltage to control a VCA . Theres no signal on it. And it attends to the impedance problem by having the output sit at 100k."

[Ubertech_s]

Hi All

I thought I would bump this up - surely someone wants a go?

My intention is to fit it in a crybaby GCB-95 - so the original wah and new volume/swell are switchable


my wah already has the true bypass/LED/Q and freq mods from Stinkfoot, well worth doing - makes a rather decent wah

http://stinkfoot.se/archives/546

Any ideas how to combine these two circuits??

after a little digging I can see the need for a 100k dual taper - is there such a thing as dual gang 100k ICAR taper, or would a compromise be dual 100k linear taper?

TIA

UT

[Travis]

Ubertech_s wrote

Hi All

I thought I would bump this up - surely someone wants a go?

My intention is to fit it in a crybaby GCB-95 - so the original wah and new volume/swell are switchable


my wah already has the true bypass/LED/Q and freq mods from Stinkfoot, well worth doing - makes a rather decent wah

http://stinkfoot.se/archives/546

Any ideas how to combine these two circuits??

after a little digging I can see the need for a 100k dual taper - is there such a thing as dual gang 100k ICAR taper, or would a compromise be dual 100k linear taper?

TIA

UT

Here's an idea for you if you can't find a suitable dual pot. It requires an extra switch to select which circuit the pot is connected to, but it will get the job done with a single gang pot

[Ubertech_s]

Thats really cool Thanks

so if I can get the dual gang pot and the vero layout for the volume circuit (above) sorted, I could use the circuit selector to switch between the wah and vol

I think I will have a go at a layout - hey how hard can it be? ;)

UT

[Travis]

Do you have a higher resolution schematic? I can draw the layout for you but I can't read some parts on the schematic

[Ubertech_s]

hopefully this is better - I uploaded it small resolution the first time without thinking

thanks

[Travis]

Here ya go

[Ubertech_s]

excellent - thankyou

Im still trying to get the appropriate dual gang 100k and work out how to get the plastic cog off the wah-wah 100k shaft

but when I have I will verify the board

thanks

Shaun

[Travis]

You're welcome! You may want to ask Joe Gagan for advice on the pot. He is the wah pot master

[Beaker]

Shaun, the gear should in theory just slide off the pot shaft as they only push on.. However in my limited experience they are a tight fit so you run a real risk of damaging the pot while trying to remove the gear. IMO you are better off buying a new replacement gear as they are cheap and easy to get.

I'm not sure where you are based, but if you are Stateside, you are spoilt for choice for Wah pots. If you are in Europe, Das Musikding and Banzai (both in Germany) have the best stock of replacement wah parts. However I have had a look and neither stock a dual gang 100k/100k. In fact I don't know anyone who makes one at all. As far as I am aware, the only dual gang that is easily available is the 500k/50k Ibanez wah pot so you might have problems.


I suggest you just buy a linear taper 100k/100k long shaft pot, just for testing purposes. It won't give you the correct "S" shaped taper curve, so won't give you as smooth a transition at the top and bottom of the treadle sweep, but it will do for starters.

I did this when I converted a dead Crybaby into a Pearl Vorg Warp Filter a while ago. It was good enough to nail down the best pot value to use (20k) and give me a good idea of how it would sound. I was then able to get a 20k Superswell pot from Das Musikding, which works superbly.

I believe Zach is local to Joe Gagan, and knows him?? He may be able to help??

If you are ultimately unable to source an "S" taper dual gang 100k/100k pot, Travis' switch idea is the way to go.

Finally, while generally I have no time at all for TGP, this makes interesting reading:


http://www.thegearpage.net/board/index.php?threads/comparing-wah-pots.801532/

[rocket88]

I felt a disturbance in the force and thought I heard my name mentioned so I came running to help. Lol.

Yea man I do know Joe and he's an awesome guy, and THE wah guy IMHO. All the ways I've built have custom wound inductors from him, and I strictly use his pots. Good quality and in the realm of things not expensive. He has such an unreal a out of knowledge when it comes to wahs and such, not to mention a really good guy. I'm not sure if he's got duals like that, but I'm sure if you contact him he'll lead you in the right direction if he's doesn't have it or can't do it for you. The best way to get a hold of him is through his eBay account, cause that's the only way he sells stuff, so if you want it let me know and I'll post it up for everyone. Not like its a secret though. Haha

[Ubertech_s]

Hi Travis

I have built this board now and not quite got it to fire

Looking at the schematic I have a couple of queries:

 I can see that IC1 [CA3080] pin 7 and IC2 [TL72] pin 8 are joined together as they should be, but should both be connected to +9V power rail? following it all back there seemed to be an issue with the position of 9V on your layout

Please have a look at the amendments below:
       9V rail moved and D2 -ve connected to it (green line)
       Also R3 requires 4.5V so Ive hooked it up to rail A, which seems to supply all other 4.5V

Ive tried to implement the amendments within the current layout, but standing the diode could be an option or moving the ground rail and adding another link. I think anyway (and I am by no means well versed in this)

Thanks UT




(edited to improve clarity)