JMI Vox - Grey Wah c. 1967

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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phibes
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Post by phibes »

Just don't expect me to do the dishes!!!!!!
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Post by sinner »

phibes wrote:Just don't expect me to do the dishes!!!!!!

Ok, now I'm hot :oops:

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Post by k1rkyd »

Hey Pawel, so have you completed your build??
If so, what does it sound like?
I stepped up on the platform; a man gave me the news; he said "You must be joking son, where did you get those shoes?"

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Post by k1rkyd »

Has anyone completed this build?? If so, please can you take some pics and share the results?

Cheers guys,
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Post by phibes »

Once the postman drops off a sweet inductor in my mailbox I'll report! :thumbsup
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Post by sinner »

Two sexy wahwah enclosures just back from painting, so possibly I'll build the grey wah tomorrow.

I have all parts to do it, correct transistors and inductor, close to dead-on caps, exact board dimension...

Tomorrow is the Gey Grey Day

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Post by phibes »

Do it!
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Post by sinner »

phibes wrote:Do it!

Done. Butt week quality. Include sloppy soldering, old shitty parts (Wima, Dale, Plessey), mojo no-RoHs solder (the secret to THIS sound) with magical amount of lead.

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Post by flatcrabs »

:shock:
that is very, very handsome.

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Post by sinner »

Thank you :hug:

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Post by whosyourdaddy »

Finished mine yesterday, it's "McCoy" with red fasel, sounds awesome, carbon comps, styroflex, mallories, BC107B (hfe 350) and BC109C (hfe 510).
buffered because of frequent use with fuzzes. ;)

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Post by RnFR »

hey, just a heads up, I found this on AMZ. check out the secondary on the 022, a very common xformer for effects.

42TU016 - Primary 380mH, Secondary 380mH
42TM022 - Primary 833mH, Secondary 261mH
42TM021 - Primary >2H, Secondary 408mH
42TM019 - Primary >2H, Secondary 343mH
42KM019 - Primary >2H, Secondary 1mH
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Post by oswaldo23 »

thanks sinner. i am from guadaajara mexico.this is the two mcoy wah .Image

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Post by Ghandi »

so, I finally got around to add a grey mod to my clyde,
just a spdt switch that changes between a 56k resistor or a second 500mH inductor parallel with my old ariel fx inductor...

and boy does that think sound great with a les paul, fuzz and a marshall! :shock:

instant pagey wah sounds!

and it is also very nice to leave in the treble position and play some semi clean, think ramble on, things on the neck humbucker!

:applause:

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Post by k1rkyd »

So did anyone try out the 250uH inductor witht this circuit? What did it sound like?
I have just today finished a circuit board for this circuit, in-line style board. I'll post later. See what yall think!

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Post by Ghandi »

I did, as I used two 500uH inductors in parallel which makes 250uH.
That's the key element to the sound of the grey wah-wah.
Without it it would just sound like a picture wah.

Cheers
Ghandi

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Post by sinner »

Hi, new layout. This is repro of the early JMI era Grey Wahwah. I had three picts only (also attached) found on-line but I think we're home with it. It match the schemo, this is what I'm sure about

Mind the transistor pinout!!!!

Oh, BTW, ins and outs are swapped around in comparison to vintage wahwah units

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Post by acidfuzz »

If anyone is curious about the palm wah circuit Vox built in to their Starstrem, Ultrasonic and other guitars, it is the same as the early grey Vox wah aside from a 33k resistor in parallel with the inductor. It also uses BC109B for both Q1 and Q2 rather than 2N3707. Other than that it's exactly the same.

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Post by deltafred »

Hey guys

I just got round to looking at the VOX Wha that was thrown in the back of the old AC30 (the one Sinner drew up).

It looks to me like a VOX Grey Wha, it is grey and has the same label as Sinner has on his website (but I'm no expert on them so could be anything).

It is gooped and has BC150 transistors. Serial number 5418. It looks to have had no mods or repairs on the board but the battery snap and pot seem to have had a soldering iron round them.

Anyone need any data or photos from it before I check it out and give it back to it's rightful owner.

I warn you it is dog rough, it looks like it has been dipped in a bucket of snot then allowed to corrode quietly for 30 years. The screws that hod the board in are corroded in solid and I suspect I will shear them off if I try and remove them now. I have soaked them in WD40 to try and loosen them but don't hold out too much hope.
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Post by sinner »

Nice, I like it. I was going to goop mine for fun as well ;)

I would love lots of pictures with macro if possible, and possibility to add that to Vintage Gallery on my website

Also, if possible measurments of the inductor (inductance and resistance) and the transistors (hfe ranges). I'll understand if it's unpossible, as you would have to use the iron to take that notes

What else... Oh, maby boards dimensions with component holes raster and spacing, mounting bolds, and stuff. One kind bloke told me his dimenssons, but I like to have it for data verification

Great stuff man, I wish I could experiance finds like that, apparently I was born in wrong part o the world ;)

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