Guyatone - WR-3 Wah Rocker 3  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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LooseCannon
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Post by LooseCannon »

Hey guys, this is my first vero layout and I picked a damn hard one to start with!

I first tried to make it fit inside a 1590B with a battery but after many hours realized it's not gonna happen... So this one should fit inside a 1590B without a battery.

Special thanks goes to Square Wave for his help with removing the switching from the schematic and answering my questions regarding it.

This is unverified so if anyone spots a problem please let me know.
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Guyatone WR-3 Wah Rocker(1).pdf
Guyatone - WR-3 Wah Rocker 3 schematic
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wahrockswitchingclean.png
WR3.png
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LooseCannon
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Post by LooseCannon »

I've just noticed a mistake- the "Out" connection should be two rows up, but I can't seem to edit my post? Admins?

I have also noticed that I didn't leave enough room for some of the offboard wire connections, for example in the 9v row.

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square wave
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Post by square wave »

Did this work on the breadboard? I'm wondering if my advice was right or wrong. :D

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Post by LooseCannon »

Nope, didn't work on the breadboard, but it's pretty complex for a breadboard so I might have made a mistake that I missed there.

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selfbg
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Post by selfbg »

Can someone recommend value for Q3? :roll:

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Post by LooseCannon »

From the other thread:
square wave wrote:Without opening a Wah Rocker and seeing what they use, I couldn't tell ya. What I would do is try several different standard types (2N5089, MPSA18, etc) and see if they have any significant effect on the sound.
Let me know if you get it to work :)

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Post by shredgd »

Hi,

I am new to this forum and first of all I would like to thank you for sharing the Guyatone WR3 schematic, which I couldn't find anywhere else.
I re-drew the schematic omitting the switching circuit to build it as a true-bypass pedal and I made a layout to use perfboard (which is what I usually use to build my pedals), so I would like to share!
The layout is as compact as possible, with resistors mostly "standing".
I built the circuit and it works! I will let you see it in a box and hear it as soon as possible.

Have a nice day!

Giulio

Image
Image

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Post by shredgd »

PS: Regarding the "nameless" transistor in the original schematic, I realized that higher gain transistors work better, since low gain ones like the 2N3904 give quite a high threshold before the "quack" starts... I wrote 2N5088 on my schematic, but I'm still experimenting and I will let you know if I come up with the "best" one!

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Post by shredgd »

I confirm that a high gain transistor is key to make the pedal work properly. An MPS18A was the best choice for me.

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AAntonio
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Post by AAntonio »

the layout version, does it work?

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Post by shredgd »

I just realized the links I posted to my re-drawn schematic and layout are broken so, as I can't edit my post anymore, I'm re-posting it with (hopefully) working links:

Hi,

I am new to this forum and first of all I would like to thank you for sharing the Guyatone WR3 schematic, which I couldn't find anywhere else.
I re-drew the schematic omitting the switching circuit to build it as a true-bypass pedal and I made a layout to use perfboard (which is what I usually use to build my pedals), so I would like to share!
The layout is as compact as possible, with resistors mostly "standing".
I built the circuit and it works! I will let you see it in a box and hear it as soon as possible.

Have a nice day!

Giulio

Image
Image

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shredgd
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Post by shredgd »

The circuit works, I just don't know if it is normal to have a very loud attack of the notes when the filter opens (I can't compare to the original one, unluckily)

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Post by amiguels »

Hello!
I would like to build this pedal, but I want to start by a breadboard. Is it possible to post the whole circuit? The left part is missing in the picture.
Thanks!

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Post by amiguels »

Sry for reposting but I couldnt find a way to edit my previous message.

Just wanted to ask where/how did you get the schematic.

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Post by soupbone »

Does anybody have a layout or schematic for the Guyatone Wah Rocker 3?It's the Quacky Pedal Guthrie Govan uses.I checked on EBay,and they're going for astronomical prices.

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Fredenando
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Post by Fredenando »

Here you have...

https://bit.ly/1lwgnT8

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Post by soupbone »

Thanks folks!

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Post by shredgd »

Great news! After all this time, and keeping my build unused in a drawer, I finally realized what was wrong with it: I compared the schematic of the WR3 with the "Dr. Quack" schematic, which is different but uses the same principle, and saw that C11 in the WR3 schematic was just too small! That's why I had to play so hard to make the "gate" open, and the loud peak I heard was just me hitting the strings too hard to have the desired effect,

So the problem was a mistake in the WR3 schematic: C11 should read "223" (i.e. 22nF, or 0.022uF if you prefer) and NOT "222" (2.2nF, way too small to pass your signal in the "wah" section).
Now the circuit works as it should: by adjusting the threshold control, you can even get the "gate" open by tapping or slapping softer or louder.

That's some real satisfaction!!

Giulio

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Post by ascianabhro »

shredgd wrote:Great news! After all this time, and keeping my build unused in a drawer, I finally realized what was wrong with it: I compared the schematic of the WR3 with the "Dr. Quack" schematic, which is different but uses the same principle, and saw that C11 in the WR3 schematic was just too small! That's why I had to play so hard to make the "gate" open, and the loud peak I heard was just me hitting the strings too hard to have the desired effect,

So the problem was a mistake in the WR3 schematic: C11 should read "223" (i.e. 22nF, or 0.022uF if you prefer) and NOT "222" (2.2nF, way too small to pass your signal in the "wah" section).
Now the circuit works as it should: by adjusting the threshold control, you can even get the "gate" open by tapping or slapping softer or louder.

That's some real satisfaction!!

Giulio
Hi Giulio
Can you repost the layout, the picture link from the above posts are not valid anymore

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