Jim Dunlop JH-1 wah-wah (90s) true bypass mod help

[camini]

Hi all,

I dug up my old JH-1 wah pedal that I bought in 91, gave it a little contact cleaner spray.

Works fine. But sucks tone too much - reason I stopped using it.

I'd like to mod it to a true bypass.
The 3pdt switch should not be a problem.

The problem I have (from the info I found so far is) is with the following 2 operations:

- the wire(s) to solder back on the PCB element. On which element should this be done on a JH-1
- what PCB track to interrupt (with a cutter) exactly

Has anyone done this mod on a 1990s JH-1 "original thomas design" wah and can you help me with this?

Thanks & regards
Camini

 

[bugg]

Can you post a few pics of the internals?

 

[Matt_Krush]

Go here:

https://www.youtube.com/watch?v=xsPh2W4a780

Has the answers you seek.

 

[camini]

Great! I will look into the provided links and also post a photo this evening!
Have a nice day!

 

[camini]

Hi,

The godwah may be a little over the top though.. my soldering iron and skills were unfortunately not godsent ��

Here are the pics, I haven't seen a PCB of a dunlop wah with the electronics set up that way (so close and so few):

Any tips, please let me know.

Have a nice day!
Cam

 

[Matt_Krush]

Here is a schematic, modern Hendrix Dunlops are layed out a little differently on the board than your older model. The circuit is basically unchanged. You don't have to physically remove the buffer portion of the circuit, you can jumper over it....I did remove the buffer circuit on my wah (in the video).

I don't know which parts/circuits are which on yours without looking at the circuit trace on the underside of the board.

 

[camini]

Wow, you did that work shown in the video? Nice.

In the video, it is mentioned that true bypass could be obtained as well with the existing switch.. did I get that right? Is that possible?

Rgds
Camini

 

[Matt_Krush]

Depends on which switch, the one you have no.
Mine came with a dual pole switch....I put in a 3 pole so I could make it true bypass and cut the battery from the circuit....so If I leave the guitar plugged in and the pedal is off, the battery wont drain.

oh....and yes...that video is my pedal and I combined as many mods together....mostly to prove what does what and which is the most influential mod(s).

The schematic above shows how your 3 wire switch is connected....you need the dual pole (shown on the left side of the schematic) and wired accordingly.

 

[camini]

Thanks Matt for the clarification on the switch.

I also found the info I was looking for here: True bypass for the Dunlop GCB-95 Crybaby | stinkfoot.se

I think my pcb is a rev E, with no buffer.
I ordered the carlin dpdt.

Tx

 

[camini]

 

[Matt_Krush]

Save your old switch....ya never know when ya may need it in another pedal.

 

[camini]

The switch arrived today.
In the meantime I had soldered the 2 new wires on the PCB and cut the track on the pcb, as per stinkfoot instructions (with a cutter).

So I soldered the switch connections and voila, it sounds like a new pedal, one that I can place in my signal chain 😊 without tone suck!

I'm so happy

Here's the finished work:

cam

 

[Matt_Krush]

Good job. So easy you'll be doing more mods to it next.

 

[camini]

Yes, maybe changing the dc input jack to a more conventional power input..

 

[camini]

Hi again,

So I further enhanced my wah pedal by installing a new pot (ICAR Deluxe 100K) as the old one was scratchy still.

Works great.

Only question I have now is concerning a 'resistor' that was installed on the old pot.. should I install it (migrate it) on the new ICAR deluxe pot or is it not needed?

Here's a picture of the old pot, with the 'resistor' in question:

Do you know what purpose this resistor serves?

Have a great day!
Regards
Camini

 

[Matt_Krush]

That's not a resistor...its a capacitor.

You can remove it.... I believe that cap was added and is for filtering out ultra high frequency (since it's 220pF)....like blocking cell phones, radio etc..

 

[Matt_Krush]

Oh...and I was right, you are doing more mods...

 

[camini]

Yes, you were right about more mods �� there was no point in keeping the scratchy pot now that I placed the wah back on my pedalboard!

When you say I can remove the capacitor, do you mean I shoul de-solder it from the old pot and put it on the new pot? Or just not use it with the new pot?

 

[Matt_Krush]

Try it without first..
If you find you are picking up radio signals, put it on.
I had an old Wah that if put in the chain a certain way, I always picked up a country station (98.5 fm)..
The Wah I built in the video, I installed a High Freq capacitor (across the foot switch) to prevent that....but it may not have been necessary...