Author Topic: Modding a JH-1 Wah  (Read 2213 times)


Modding a JH-1 Wah
« on: July 24, 2017, 06:19:33 PM »
This is my third time ever at modding.  My first two times have come out very satisfactory to myself.  I'm a total novice.  I'm trying to learn and try to stay real humble.

Please allow me to tell you about my first two mods.

1.)  My 1994 Dunlop GCB-95 had a scratchy pot which I successfully replaced.  I wanted to try out a yellow Fasel inductor inside of it also, so I put one in, replacing the N30 one which I still have.  An internet modder friend suggested I put a trimpot in to adjust the "Q" which I did and dialed in exactly the way I have in another wah I have the CAE MC404 dual Fasel Wah. 

2.) I put a socket inside my Rat2 distortion, which did not sound bad at all as it was.  I put in a National brand LM308 opamp in it.  I did not really notice any great change in tone for the better.  I therefore put back the original Texas Instrument opamp it came with.  I recently came across some of the Motorola LM308 metal can opamps which I will get to try in the Rat2 after I do my next mod.

On the JH-1 Wah I plan on doing the following mods to it:

1) Replace Q1 Transistor with 2N3900A
2) Replace Q2 Transistor with 2N3391A
3) Replace sweep capacitor with mylar/film .01uf capacitor
4) Put in a 1 K Ohm trimmer to adjust the Q

This is my first post on here I hope it does not appear too odd.

I've read and taken advice from some on here on the hFE values for the transistors.
I have two of each for both I'm replacing and the values are
2N3900A  313 hFE and 319 hFE
2N3391A  412 hFE and 329 hFE
« Last Edit: July 24, 2017, 06:22:58 PM by TOBOR »


Re: Modding a JH-1 Wah
« Reply #1 on: July 25, 2017, 08:14:31 AM »

About the OpAmp, don't believe the hype. Most of the time (if not all) replacinf it has no effect.

Scarlett Johansson uses a Burst Box with her Telecaster.

Kirk Hammet invented the Burst Box.


Re: Modding a JH-1 Wah
« Reply #2 on: July 25, 2017, 10:17:44 AM »
I did not know Scarlett even played guitar.  I really love her!  She makes me feel good with her acting as well as the way she looks.  She is a total babe!


Re: Modding a JH-1 Wah
« Reply #3 on: July 25, 2017, 10:24:21 AM »
I did not notice any particular improvement in tone when I changed out the opamp.  I number of us who have actually tried this mod have notice this as well. I need to put some kind of cool avatar photo for myself on here.  I feel like an amateur on here.  I plan on trying to increase my knowledge in electronics.  After I become comfy with pedals I feel it would be most delightful to work on and build a project amp.


Re: Modding a JH-1 Wah
« Reply #4 on: July 25, 2017, 10:40:37 AM »
TOBOR - also welcome. don't believe everything you read here about Ms. Johansson - there are many flights of fancy launched hereabouts. and, if you ask one of the moderators nicely, they might move this (your) thread to the general board instead of this area, which is meant for a specific beginners project. more people will then see your post.

and - those transistors - odd numbers, where did you dig those parts up? make very careful with your orientation of them, from what I can see they are both end-base package (as opposed to centre-pin base layout). I don't know hoe that fits with the parts in the original wah.
"I think we're done here."


Re: Modding a JH-1 Wah
« Reply #5 on: July 25, 2017, 10:54:37 AM »
Thank you for letting me know regarding the transistors.  I will follow the proper pinout on them.  You are right that they vary from the transistors I have.  I've taken notes and double checked everything on my two mods I performed before.  I'm taking the same approach with this one.