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 he


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



Gareth.

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

Peter Wieck
Melrose Park, PA

On Wednesday, July 26, 2017 at 3:51:02 PM UTC-4, Gareth Magennis wrote:


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


Gareth.

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

Gareth Magennis wrote:

-------------------------

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.


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

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.



** 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

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