May Queen "crazy" control---how to build it?

[cheezit]

Longtime lurker here...been away from pedal-building for a bit but I'm back.  And I've got what I think is an odd question.

I built the May Queen from the ROG site on pad-per-hole board---I've had my eye on this for a couple of years.  Looked great, couldn't wait to try it out.  So I bust out my alligator leads to hook up the 9v, ground, in and out. And after fixing one little break, I was in business. 

How did it sound? UNREAL. It has the boosted mids of May's tone, but also a sort of chirpy attack and whistling decay, like an amp that is just about to explode.  Like Eddie Phillips (the Creation)---almost out of control.  Love it!!

So, time to get serious.  I box it up in a nice enclosure, hook up all the ins and outs and try it out.  How does it sound?  Still very good, but it's now been....tamed.  The chirp and character is toned down.

So after bit of thought, I decide to hook up my alligator leads to my boxed-up circuit, one to the input jack, and one to the output jack, and see if maybe the dangling one-foot wires contributed.  Yes!  The insanity is back!!  If I move the wires close together, the craziness returns, if I move them 2-3 inches apart, it goes away.

Now I need to bottle this magic and turn it on and off.  I think this is actually signal coupling, induced somehow through the air gap between the wires. What can I do to replicate this inside the box?

I tried a resistive load (4.5M) between in and out, but that just gives me a wolf-tone.  I remember reading Anderton's book forever ago and he had a circuit where you could either use a very low (10pf or so) cap OR sub in two wires twisted together, which sounds similar but not the same.

Any ideas?  thanks in advance...

[Earthscum]

Maybe make a filter, series 1M pot and maybe 220pF cap? It might get the low wolfy sound because it's getting all the signal fed back. 1M and 220pF will only feed back above about 723 Hz, and as you decrease the resistance, it will only let the higher signals feed back... then you should be able to find just the right tone. If it gets close, but you're rolled all the way down, try a smaller cap. You may try just a small cap to feed back, but I think the filter might let you tune something in, then you can take a measurement and drop a resistor in place of the pot.

[Jdansti]

What if you replace the alligator leads with 1ft of paired wires such as the type of wires coming out of a wall wart, speaker cable, or lamp cord. If one of these types of wire work outside of the box, see if you could bundle them up in such a way as to keep the cool sound and fit them inside the enclosure. You could switch the magic wires in and out.

[brett]

Hi
I'm no expert, but I suspect that most cable (e.g. speaker cable) is designed to keep the conductors a couple of mm apart to minimise cross-talk. You might do better finding wires with thin insulation and taping them together. I suggest that you don't twist them, as that can have a noise-cancelling effect. And keep them away from the case (a couple of mm).
cheers

[cheezit]

thanks guys.  I tried a 200n cap in series with a 1M pot and got more wolftones.   I used my dmm to see what the measured capacitance is between the disconnected wires, and bringing them close together raised it by 40n...that's a lot.  And i bought these a smallbear.  Anyway, I tried the same cap+pot but with a 20n cap, and it came closer, but still oscillated and whistled when everything was full up.

I know the electrical characteristics of a pickup can be modeled as a combination of a resistor, an inductor and a capacitor.  But that leaves out the actual signal transfer, of course. 

The cap+pot approach might (with the right values) emulate the electrical characteristics of the dangling wires, but it doesn't replicate the signal transfer.  I suspect that the two wires have particularly crummy insulation (hence the measured capacitance) but more than that I think there's some audio-band signal coupling going on.  Like an audio transformer, maybe...since the transformer's job is to 'induce' voltage in an electrically independent coil via the core....hmmm...