Can someone explain why bleed-over occurs in true bypass loops?

[hallenj]

Hi,

I am trying to understand how a true bypass loop switch works.  I have one from Radial Engineering called the Big Shot EFX.  When one of the loops is selected but the receiving jack from the effects loop is left unconnected, I can hear a faint bleed-over from the input guitar signal.  I don't understand why this happens if the design is true bypass.  How does that guitar signal get passed through to the output?

For example, if I send my guitar signal through the loop into a tuner and do not send the signal back to the looper from the tuner, there is bleed-over of the guitar.  It's also distorted.

I noticed that on Loop-Master's FAQ, he acknowledges that there is a faint bleed-over in his true bypass switches under the same condition.  Again, can someone explain why?

Thanks very much!
Jason

[hallenj]

I see that I've posted this in the wrong thread.  I'll move it over to the proper one.  Sorry!