Mysterious Popping when effect is engaged

[goldstache]

Hey I built an overdrive, this is the 25th one of the same circuit that I've built.  Here's my problem:  When Engaged the pedal pops LOUDLY.  Pull down resistor is in place and I even ran a separate resistor off of the 3pdt switch pin to effect to ground to check and still lots o' POP.  What gives?

When bypassed the input is grounded so there is no pop when disengaging effect.
What am I missing here?
Bad switch???
Help Please!!!!

[R.G.]

Hey I built an overdrive, this is the 25th one of the same circuit that I've built. 

So business is good, yes?

[goldstache]

Yeah once I stop giving em' away I suppose It will!!!  HAHAHHAAHHAA
R.G.- what do you think about the poppin'

[Pyr0]

What overdrive is it ? Do you have a link to the schematic ?

[goldstache]

rick holts z drive clone
http://circuitworkshop.com/forum/index.php?topic=542.0

[amptramp]

Chasing the links takes me to a schematic that cannot possibly work:



There is no bias return for the U1a non-inverting input.  The layout looks different.  Do you have a better schematic?

[goldstache]

OK sooooo....... It turns out Im blind and with a bad case of the Newb!!
I didn't follow my True Bypass wiring!
Totally swapped current limiting resistor with, ground pin on 3pdt switch.   Sorry for the waste of internet space.

And as always thanks for your Help!
Cheers!