Wah Inductor Build

[Arn C.]

Just wondering if anyone knows where I could find some specifications for winding some Wah Inductors:  type of core, wire size, etc....
Thanks!
Arn C.

[BillyJ]

Hey Arn,

If you look back on some of my posts I found some stuff that is interesting but not sure if any of it will help.
I have found two core types that have the right ID numbers but not the right size....evcen though I thought those numbers were realitive to their size...in any event take a look at those posts if you can
If anyone has any ideas about the questions I posed perhaps I can send you some good stuff.
I do believe ther is some copper wire at the same place suitable for just this.
No one answered at the time so I kinda shelved it but I was thinking if nothing else these cores might be able to be stacked and run in parrallel.
Well anyway I have been meaning to get you a little care package together so maybe I will just toss those in too and you can fiddle with them.
Anyway do look up my posts about wah cores!!

[Arn C.]

Thank you Billyj!
I have just about every size wire and a bunch of different size and kinds of cores available to me.   I may take my vox inductor, not (stack of dimes) apart  and reverse engineer it.  My friend where I work is an engineer and deals with this sort of thing everyday.  If I get anymore info, I will also let you know!
Thanks again!
Arn C.

[BillyJ]

Yeah I have some junky dunlop inductor I have been planning to tear apart.
From waht I can see of this one it looks as if it is wound on a plastic bobbin then inserted into the coil?
Weird. I need to tear it apart and  see what is up.
I am thinking that the coils I have are too short so I was thinkg I could somehow stack them and wire them in series..
You'd think I could just go and buy a Fasel for $20.00 and be done with it But NoOOOoooo!  
I just found the envelope you sent me so I'll be putting together something for you here real quick.
Yeah let's keep the info pool growing. Anyone else want to put their two cents in?
I know at least one other person was on this quest in the past.
Fun stuff... Now I just need to know how to make an eclsoure from scratch.
"Sonny hand me that chunk of aluminium and my whittleing blade." LMAO!!

[Arn C.]

I am still searching around for some more info BillyJ.   Like I said, I have all I need at my disposal to make these.   I just need more info on what the core is : size, material.   Also what size wire, howw many turns, etcc...  I will keep you informed!!!!!                                                                                          Peace!   Arn C.

[BillyJ]

I am assuming you have seen these pages:
http://www.green-fuz.freeserve.co.uk/wah.html
http://www.green-fuz.freeserve.co.uk/inductor.html

And some where in the archive I have seen some math equations that I think are to determine how many turns etc.
If I can find the time i will try to look that up again and post.


This is what weirds me out:
"The original halo and film can inductors used P18/11 pot cores (18mm diameter, 11mm tall)."

I have one core here that is numbered 1811P and also 3B7.

If the 1811 is supposed to be referencing size than I don't get it because mine are not that tall. Mine looks aprox. five to six MM tall.

I also found a core labeled 1408A with a second line: 315 3CB

Well anyway sorry I don't know more about the math involved and construction
I had planned to but kinda got sidetracked when I ran into thew size weirdness.

Someone should just email one of the guys that do this like Castledine.

Anyway I will post anything I can find out..

[al3151]

I had ask this question before and got as a response a technical page(I have to find the Link)with a mathematical formula witch really didn't help me...you know on account of my sloping forhead and small brain :lol: .I wanted to "clone" the old wah inductors.I wanted to know the exact recipe.Those who know aren't telling and its perhaps the best kept secret on the net.I had a couple of inductor cores that I was going to try and wind my self using wire from an old pickup but never got around to it.

[Pedro Freitas]

From what I've built it seems that the inductor isn't a super critical part to make a wah. I strongly urge you guys to pay a visit to the junkyard. Ask for the place were they dump or store the coils, copper bobbins, relays, tansformers and you'll get lots of wire to keep winding wah inductors 'till your 70  :lol:  Small relay coils for audio pourposes are exelent because the wire is very very thin!

Ask for the place where they dump or store PCBs. There are literally hundreds of ferrite cores there just waiting to get unsoldered. The ones I've been most sucessfull with are those round ones that split in half (stack-o-dimes inductor), just make sure you unsolder the locking pins that hold the two halves togheter.

All you have to do is unsolder one of this suckers out of the original PCB, split them open without bracking the plastic core (or the ferrite) to pieces because sometimes the manufacturer puts rock hard glue on them, remove the existing wire, rewire the bobbin to 500mH spec   , put the bobbin inside the two ferrite halves again (submerge it in brown epoxi to conceal your ultra high-end wah inductor   ) and mount it in the wah PCB.

You have to have an inductance meter, they are becoming cheaper and it helps allot!!! Winding the bobbin has been a process of trial and error for me because I can get many different sizes and shapes of ferrites. Usually I over-wind with extra wire, mesure it and then take out the excess wire in small amounts. There is no mathematical formula for this. I also noticed that those cores I've mentioned are very very susceptible to pressure and relative position of the 2 halves, so, that should explain for the drift mass produced wah inductors present. Don't bother. Just try to make one around 500mH and 50ohm resistance (20 to 70 ohm will be fine this depends on the diameter of the wire)

yours,
Pedro

[BillyJ]

I see so they use two core each as a half... I see that makes sense again as mine are 5.5mm (guessing) and two would be 11mm...Sweet one step closer.  

[Pedro Freitas]

Hello!
Visit this link:

http://www.green-fuz.freeserve.co.uk/inductor.html

It's in Stuart Castledine's site. The ferrite cores I was talking about are the halo ones, very similar to these ones, size and shape wise. Sometimes they don't have a hole in the centre for the screw so they use 2 pins or a metal belt to secure the two halves.
Size isn't really important.

If you'r really stuck get a small toroid core and a tinny relay switches from your local electronics shop and wind your inductor with that. It's very laborious :evil: (if your wire gets short of the 500mH just get some more, solder the 2 ends and keep winding. No problemo) but the result is just the same. And don't put epoxy directly over the wire if you wind on a toroid! The epoxi will shrink when drying and alter the inductance.

Happy winding,
Pedro