[sdiy] Jim Dunlop Cry Baby Wah-Wah.. 500mH inductor replacement with an inductor simulator circuit.. Feasable ?? follow up..
Neil Harper
metadata at gmx.com
Tue Jun 18 21:01:40 CEST 2024
Alternate devil's-advocate option:
Ditch the pedals that require an AC-AC source, buy similar ones that can
take 9VDC and get a single Voodoo Labs power supply to power everything
(these use torrodial transformers, isolated for each output).
--
/// Neil Harper
/// Every Wave is New Until it Breaks
On 2024-06-18 10:21, Mr&MrsAccount wrote:
> I had a similar issue with a hex fuzz, my problem was the transformer
> has a lot of leakage inductance (magnetic field escaping the core, which
> used the metal case as a shorted secondary turn and raised hell.
> I tried to shield the transformer with mu-metal, which solved the
> problem, but got hot as hell. The shorted secondary was now really
> tightly coupled.
> Best way, move the transformers outside of the case, or put them in a
> separate steel box inside the case. Alternately you might want to use
> switching power supplies as someone else suggested.
> You could use a toroidal AC transformer which tend to not leak external
> fields if you still want linear supplies. They have be expensive and
> hard to source.
> I'm a big fan of keeping 60Hz (or 50Hz) AC transformers outside of effects.
> Harry Bissell
>
> ------------------------------------------------------------------------
> *From: *René <synth at schmitzbits.de>
> *To: *synth-diy <synth-diy at synth-diy.org>
> *Date: *Tuesday, 18 June 2024 9:39 AM EDT
> *Subject: *Re: [sdiy] Jim Dunlop Cry Baby Wah-Wah.. 500mH inductor
> replacement with an inductor simulator circuit.. Feasable ?? follow up..
>
> Actually pot cores have been used by Dunlop in their pre 1990s crybaby.
>
> https://www.electrosmash.com/crybaby-gcb-95
> <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>
> <mailto:pfperry at melbpc.org.au>
> Sent: Jun 14, 2024 6:26 PM
> Cc: <synth-diy at synth-diy.org> <mailto: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 <mailto:tom at electricdruid.net>> wrote:
>
> Yes, exactly!
> Tom
>
> On 14 Jun 2024, at 19:29, Jean-Pierre Desrochers
> <jpdesroc at oricom.ca <mailto:jpdesroc at oricom.ca>> wrote:
>
> This schematic is a later generation… with input buffering :
> <image001.png>
> *De :* Tom Wiltshire <tom at electricdruid.net
> <mailto:tom at electricdruid.net>>
> *Envoyé :* 14 juin 2024 13:52
> *À :* Jean-Pierre Desrochers <jpdesroc at oricom.ca
> <mailto:jpdesroc at oricom.ca>>
> *Cc :* synth-diy at synth-diy.org
> <mailto: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
> <mailto: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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