Switch popping with 18volt charge pump

[MelodiusMaximus]

Sorry if this has been discussed before, but  could not find the answer using the search function.   So any help is much appreciated.  

I have built a booster/ overdrive pedal utilizing a MAX 1044 for 18volt charge pump.    But when switching the effect on/off, I get an extremely loud popping noise.   Tried pulldown resistors (1M, 2.2M,and 4.7M) on both input/output but did not help.   Also tried replacing switch, replacing possible leaky in/out caps, and trying various wiring configurations on switch/grounds/etc, but no luck.   BTW, I am using a DC 9v adapter with battery input jack trick.  Has anyone experienced this, and what would you suggest?

[toneman]

Is your voltage "center point" at 9V or 4.5V??

inquiring minds & fingers


staycentered
tone

[MelodiusMaximus]

Is your voltage "center point" at 9V or 4.5V??

Not sure exactly what you mean by centerpoint, but I am supplying 9 volts into  MAX 1044 and then to Vr which feeds into non-inverting input of opamp.

[toneman]

By Vr I *guess* U mean Vref, or the "centerpoint" of your
highest voltage.   Since U seem to B running the OA on
18V (and gnd) now, the new "centerpoint" needs to B
1/2 of 18V, not 1/2 of 9V.
MuddilyClear?

EDIT: If U R running the OA on plus-&-minus 9V,
(using the CPump to make a -9)
which IMHO is better than uni-polar,
"gnd" is automatically your "centerpoint" ,
which should give U the *least* problems of all.  
OA are designed to run on a bi-polar voltage.
MoreMud?

staycentered
tone

[MelodiusMaximus]

I'm running charge pump uni-polar and Vref is 1/2 of 18v.   Neg input of OA supplied with Vref, +V at 18v,  -V to grnd.   Would using bipolar Cpump reduce pops?