Switchcraft 12A jacks: bleedthrough???

[Skreddy]

Anybody else experience a signal bleedthrough from the normally-closed shunt on Switchcraft 12A jacks when something's plugged in and the switch is open?

If anybody's making loop boxes with normallized send and receive jacks using Switchcraft 12A's, I recommend you double-check your finished product using a very high gain pedal at maximum volume to see if it squeals.

edit: oops; I said "11A"

[goosonique]

Yup, high gain bleed through usualy goes away if it's boxed up...try keeping build neat and not too squeezed up(seperate input and output as far as possible). Try also turning the hot side lug closer to the enclosure wall .....I have fixed some pedals with similar problems by just doin the above.
Btw Skreddy... nice builds and customer support...

[Skreddy]

Thanks, goosonique!

I'm going to do some more forensic analysis.  I don't think it's possible to have shorted the tip to shunt by simply bending the tip's solder lug all the way down.  It looks like the jack is made to allow for that and still have about a millimeter of clearance to the ring below carrying the shunt signal.  So what I'm considering right now is something very strange and unlikely... that the mere capacitance of the shunt is coupling the signal.  The rings are parallel in the jack, sandwiched with a small layer of epoxy/fiberboard, and then the shunt follows the tip very closely parallel for nearly an inch up to the point where they make and break contact...

http://www.switchcraft.com/products/pdf_files/jack-85b_schematic.pdf