[sdiy] Jim Dunlop Cry Baby Wah-Wah.. 500mH inductor replacement with an inductor simulator circuit.. Feasable ?? follow up..

René Schmitz synth at schmitzbits.de
Tue Jun 18 15:30:32 CEST 2024


Actually pot cores have been used by Dunlop in their pre 1990s crybaby.

https://www.electrosmash.com/crybaby-gcb-95


Best,

  René


Am 18.06.2024 um 01:36 schrieb BrightBoy via Synth-diy:
>
> I know there have been some companies that have offered mu-metal 
> shielding kits
>
> for wahs BUT I have no idea if any of them still do these days.
>
> Let Google be your guide.
>
> Cheers,
>
> Jeff
>
> -----Original Message-----
> From: Paul Perry <pfperry at melbpc.org.au>
> Sent: Jun 14, 2024 6:26 PM
> Cc: <synth-diy at synth-diy.org>
> Subject: Re: [sdiy] Jim Dunlop Cry Baby Wah-Wah.. 500mH inductor 
> replacement with an inductor simulator circuit.. Feasable ?? follow up..
>
> This may be heresy, but replacing the original inductor by a toroidal 
> wound one would prevent picking up external fields.
> There are also ferrite pot cores (that's pot as in shaped like a pot) 
> if you feel experimental.
> paul perry Melbourne Australia
>
> On Sat, Jun 15, 2024 at 5:18 AM Tom Wiltshire <tom at electricdruid.net> 
> wrote:
>
>     Yes, exactly!
>     Tom
>
>         On 14 Jun 2024, at 19:29, Jean-Pierre Desrochers
>         <jpdesroc at oricom.ca> wrote:
>
>         This schematic is a later generation… with input buffering :
>         <image001.png>
>         *De :* Tom Wiltshire <tom at electricdruid.net>
>         *Envoyé :* 14 juin 2024 13:52
>         *À :* Jean-Pierre Desrochers <jpdesroc at oricom.ca>
>         *Cc :* synth-diy at synth-diy.org
>         *Objet :* Re: [sdiy] Jim Dunlop Cry Baby Wah-Wah.. 500mH
>         inductor replacement with an inductor simulator circuit..
>         Feasable ?? follow up..
>         Ok, so it's clear that yours is one of the original old-school
>         Crybabies. Nice.
>         It may not sort out your current issue, but you should really
>         try putting a buffer between the guitar and the wah. At the
>         moment, that input transistor with its low impedance is
>         hanging off your input signal and killing the treble, even
>         when the wah is switched out of circuit (the switch only
>         switches the output). That will affect the whole rest of the
>         pedal chain.
>
>             On 14 Jun 2024, at 15:54, Jean-Pierre Desrochers via
>             Synth-diy <synth-diy at synth-diy.org> wrote:
>             To answer some questions :
>             */….. With so many power sources, you may be hearing a
>             ground loop.  Never assume that the common return of
>             multiple power sources are all the same potential./*
>             There are no ground loops in my pedal board. Unselecting
>             the Wha makes the 60hz hum completely go away.
>             And placing the inductor in a specific way in the Wha
>             metal box almost kill completely the hum.. so no ground
>             loop for sure.
>             */….. I'd start by looking at some of the *other* pedals
>             to see how many could be converted to standard 9V
>             centre-negative, and then reduce the number of
>             transformers to reduce the noise./*
>             > 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
>             *The 4 x AC powered pedals :*
>             *2 x LINE6 modelers that could be run using 6VDC supplies
>             (they can run on 4 x 1.5vdc C cells) eliminating two
>             transformers..*
>             *1 x Blackstar DS2 powered by 16VAC (no possible DC
>             powering):*
>             *<image001.png>*
>             *1 x Electro Harmonix Hum Debugger pedal powered by 7.5VAC
>             (no schematic available)*
>             The following pictures shows the real actual schematic of
>             my Wha.
>             It’s an Italian Jen Cry Baby with a FASEL branded inductor.
>             The bottom picture shows what I’ve done to ‘place’ the
>             inductor at the ‘sweet spot’ to get the less hum possible.
>             Not bad..
>             But a shielded inductor could be fine (but expensives..)
>             And again, this is not a ground loop problem..
>             <image004.jpg>
>
>
>
>                     On Jun 13, 2024, at 4:46 PM, Jean-Pierre
>                     Desrochers wrote:
>                     > 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..
>                     > Now I can play with a little back ground hum
>                     when the Wah-Wah is activated..
>                     > I  was wondering if I could use an active
>                     inductor simulator circuit
>                     > In place of the 500mH passive inductor.. (??)
>                     > Feasable ??
>
>
>
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--
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