[sdiy] Jim Dunlop Cry Baby Wah-Wah.. 500mH inductor induced HUM.. resolved !

[Jean-Pierre Desrochers]

Working hard to find a solution to adequately

shield my Wah's inductor from any induced 60hz HUM
coming from surounding transformers here is what I finaly did :

Remove almost all of my AC power transformers (kept only one)
and replace them by a small SMPS multiple output 9VDC supply.

 

I've been able to shield acurately the inductor using a small piece of car
shelter pipe (iron/steel aloy)
cut the lenght I needed and ended (welded) with a small
nickel coin.  (YES a nickel coin !) Grounded with a small wire
and placing it over the small inductor, That made the trick !

 



 

I'm now happy with the final result.. (No expensive MuMetal $$$ solution).

 

JP

 

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> I have a guitar pedal board that uses 8 pedals.

> The first pedal (receiving the guitar) is a Jim Dunlop Cry Baby Wah-Wah.

> The following pedal is a switchable  overdrive with high gain.

> Then the pedal chain goes on with 6 other pedals to a final tuner that
drives a guitar amplifier. Ok.

> 4 of these pedals are powered with there separate AC supplies (9VAC, 9VAC,
7.5VAC & 22VAC).

> The other pedals are powered using 9VDC standard BOSS supplies.

> Here is my problem :

> Since the Wah-Wah is connected at the 'head' of the pedal chain and uses
an internal 500mH inductor in its circuit

> it acts like the secondary of a transformer picking up 60Hz

> from all the nearby transformers of the board.

> I had to unsolder the inductor from the inside PCB and,

> using short lenghts of wires connected to it . place it in the Wah-Wah
housing

> at a 'specific' place and angle to get the less 60Hz pickup.

> This is annoying.. 

 

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