Dunlop CryBaby into tansformer

My test bench has for many years had a couple of ground isolated Neve 1:1 transformers between XLR input test sockets and stereo monitors.

Which has never been a problem, but has ALWAYS been a problem connecting any CryBaby Wah Wah pedal.

If you do, the CryBaby resonates at full volume, behaving much like turning a VCF resonance control to full, so it self oscillates. Why is that?

I guess that means you could never directly connect a CryBaby to any transformer balanced mixer input.

Circuit here:

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Gareth.

Reply to
Gareth Magennis
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Just for giggles, have you tried reversing the plug polarity?

Peter Wieck Melrose Park, PA

Reply to
pfjw

Just for giggles, have you tried reversing the plug polarity?

Peter Wieck Melrose Park, PA

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No,I thought as it is transformer and ground isolated it shouldn't matter.

Gareth.

Reply to
Gareth Magennis

Just for giggles, have you tried reversing the plug polarity?

Peter Wieck Melrose Park, PA

******************************************************************

No,I thought as it is transformer and ground isolated it shouldn't matter.

Gareth.

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The output goes into an inductor, the CryBaby doesn't seem to like it.

Gareth.

Reply to
Gareth Magennis

If you have the typical "Hot-Neutral" configuration, it does - well - better stated, it can. It does not matter only with hot-hot configurations such as US 240V single-phase connections. Try reversing, and please let us know.

Peter Wieck Melrose Park, PA

Reply to
pfjw

If you have the typical "Hot-Neutral" configuration, it does - well - better stated, it can. It does not matter only with hot-hot configurations such as US 240V single-phase connections. Try reversing, and please let us know.

Peter Wieck Melrose Park, PA

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Hi Peter, I think you have the wrong end of the stick.

This is a guitar effects pedal, a "Wah Wah". It is a resonant circuit that emphasises mid frequencies to produce vowel like sounds when played with a guitar.

The "problem" I have always had is that you cannot connect this to a transformer based pre-amp, as it would seem the inductive load affects the circuitry in a way that seems to make the resonant circuit resonate like crazy. This unit is intended to plug into a guitar amplifier, not a transformer based test bed, where it misbehaves.

Gareth.

Reply to
Gareth Magennis

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** Are they toroidal, red coloured with black potting in the centre ?

** You need an active DI for that job, preferably with JFET input.

Maybe you could add 48V phantom for it to one of the XLRs with two 6.8kohms.

...... Phil ..... Phil

Reply to
Phil Allison

Gareth:

I know what it is - I have repaired a number similar devices for my neighbor. I suggest what I suggest due to (limited) direct experience with such devices.

If you try this suggestion and it works, good. If not, no loss.

Next thing to look for would be cold-solders or poor connections - most of what I fixed for my neighbor.

Peter Wieck Melrose Park, PA

Reply to
pfjw

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** Are they toroidal, red coloured with black potting in the centre ?

** You need an active DI for that job, preferably with JFET input.

Maybe you could add 48V phantom for it to one of the XLRs with two

6.8kohms.

...... Phil

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I always just put it through a guitar amplifier, there is usually one around.

Oh, I checked today and my bench doesn't actually have Neve transformers, I used them for another project and got confused/forgot. They are indeed the orangey coloured toroids with potting in the middle, with a threaded insert for mounting.

The ones I used on my bench are pretty much the ones BSS used in their AR116 DI boxes.

Gareth.

Reply to
Gareth Magennis

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** So it used to have Neve transformers or never had them ?

You are an expert at ambiguous posting.

** Yes, that is the same kind I have seen recently.
** Potted in a Mu-metal box ?

Made by OEP and sold by Farnell ?

..... Phil

Reply to
Phil Allison

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** So it used to have Neve transformers or never had them ?

You are an expert at ambiguous posting.

** Yes, that is the same kind I have seen recently.
** Potted in a Mu-metal box ?

Made by OEP and sold by Farnell ?

..... Phil

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Sounds pretty likely, I bought them a long time ago.

Gareth.

Reply to
Gareth Magennis

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** Look like them ??

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.... Phil

Reply to
Phil Allison

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** Look like them ??

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Probably decided at the time I didn't really need the mu-metal casing, but yes, this is the type I got. Don't know what impedance, but got 1:1 versions.

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The 4 Neve donuts went into a couple of isolator boxes at live gigs. Still use one box between the live system and the recording laptop / soundcard.

Gareth.

Gareth

Reply to
Gareth Magennis

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