Fx loop issue

Hello. I built this serial fx loop as drawing below. It work very well with two small issues: First it raise a bit of noise - very extremely slight but still here when 5ft. patch cables connects.(I can pass that). Second it slightly pops when I engage any pedals I have ( not any external noise, just popping when engage the foot switch). All my pedals are supplied from mains from 9V independent smps adapter supplies. Please help how I can cure the popping noise when pedals engage please ? Thanks.

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The level of noise is dependent by 100k pot position. More loud as the pot is more open. Should I isolate the recovery stage input with a cap please ?

Late: oh no, a cap at input recovery stage did not do a difference...more, it seems it pops a bit louder than before...A capacitor from the whiper output to pedal input did not helps either...
There are not ground loops, supplies are galvanic isolated by separation transformer...just a comute regime I cannot get rid of...
 
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If I take the cable from CF output out and left just recovery stage input connected at output of pedal (cf output disconected) I still hear a very discrete pops when engage the foot switch but Is a huge difference. How could I tame the loud pop when cf is connected to the same discrete pop level when just the pedals output is connected, please? Thanks
 
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