Kent WT-1 (Shin-ei) wah

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

This morning at a pawn shop I picked up a Kent wah for the princely sum of $19.99. (I don't know why I bought it since I'm not a wah-wah kind of guy and the only time I get an urge to buy one is when I listen to the first two Stooges albums.)

I opened it up at home and saw the Shin-ei logo on the insides of the bottom plate:

Image

It works, but the wah pot's a little scratchy. I was expecting it not to work at all.

Does anyone know what year these were made?

Some info:

http://www.effectsdatabase.com/model/kent/shinei/wah

http://www.effectsdatabase.com/model/sh ... panion/wt1

http://www.dirk-hendrik.com/shin-ei.html

More pictures (including a schematic):

Image

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I don't know how accurate the schematic is. It shows a 50K wah pot, but the pot in the pedal is 100k.

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jrod
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Post by jrod »

Great score, man! Thanks for sharing the pics!

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sidseizure
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Post by sidseizure »

I just went through the board and tried to identify the various parts and they're a bit different than what's on the schematic.

Capacitors: two .22uF, one .033uF, two electrolytics that are only marked Tracon 10/25.

Resistors: two 470k, one 47k, one 470, one 22k, one 1.5k, one 10k, one 100k, and one 1k.

The one transistor that I can read is a 2sc536F.

I think I can take the board out easily so I can take a photo of the trace side.

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lolbou
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Post by lolbou »

sidseizure wrote:two electrolytics that are only marked Tracon 10/25
Stands for 10µF / 25V. :wink:
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.

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Post by sidseizure »

lolbou wrote:Stands for 10µF / 25V. :wink:
Makes sense. :D

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sidseizure
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Post by sidseizure »

OK, as promised, here's a shot of the trace side of the board:

Image

And for absolutely no reason other than it amused me, here's the stomp switch with a tiny Shin-ei logo on it:

Image

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kaycee
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Post by kaycee »

Nicely documented post! Well done and thanks!

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Post by sidseizure »

Since I don't know anything about wahs, I've been doing some research. I found out the Shin-ei wah circuit is based on the Vox. I ran across a good comparison of the various Vox wahs, Crybaby, and others that all use the same basic circuit:

http://www.aronnelson.com/gallery/main. ... ewsIndex=1

And the information in the above came from R.G.'s great article "The Technology of Wah Pedals":

http://www.geofex.com/Article_Folders/w ... wahped.htm

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sidseizure
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Post by sidseizure »

Biffa, I may just replace the guts with new stuff. I don't know if I want to try and repair this thing or not. It produces white noise and static which only gets worse if I put it in front of a fuzz or distortion and I have no idea where to start to remedy that. (Oddly, the scratchy pot situation has disappeared with use.)

I was hoping someone else had one of these and could provide some gut shots for comparison.

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Post by Solidhex »

Looks stock to me. Just because the components aren't consistent with the schem doesn't mean they aren't original.

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Post by lolbou »

Solidhex wrote:Looks stock to me.
+1
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.

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Post by Solidhex »

All the parts look consistent with what they were using in those pedals back then. You'll most likely see the triangular Matsushita logo on the other side of those caps. Trace side looks undisturbed as well. Its probably from the same era as this FY-2 on the Uzzfay site which is in even cleaner shape... http://members.fortunecity.com/uzzfay/fy2/fy2parts.html
It wouldn't surprise me to see a replacement wah pot since most Shin-ei wahs I run into have bad pots but the wiring all looks factory fresh.
Unfortunately the Shin-ei wahs usually sound like ass so you might as well build something fun in there! Either that or swap out some stuff and make it a Clyde or Colorsound circuit. Don't step on it too hard either. Those hinges that attach the treadle to the base are CHEESY!

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Post by analogguru »

Resistors: ........, one 1.5k, ...... and one 1k.
:hmmm: Why I can´t see the one 1k, but instead two 1k5 ? :scratch:

analogguru
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Post by sidseizure »

analogguru wrote::hmmm: Why I can´t see the one 1k, but instead two 1k5 ? :scratch:

analogguru
I just took the bottom off the pedal to check again and there's one 1k and one 1k5. In the picture below the 1k is circled.

Image

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Post by analogguru »

Thanks for the info. On my computer the second color band on this resistor has a green touch.

analogguru
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Post by fuzzbuzzfuzz »

Same wah circuit I believe as in my current repair project a ELK wah fuzz. That has the fuzz built on a wider board, components look the same. I actually dig the sounds of these!

Replace the electrolyte cap?
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