Ross phaser true bypass popping question

[jrc4558]

Hi everybody!
I have recently built a tonepad's Ross Phaser http://www.tonepad.com/getFile.asp?id=47 It works like a charm, nice and smooth phaser. However, when I tried to box it up, I encountered a problem with really loud popping when switching the effect in and out. I have added a pulldown resistor on the input, before the 1k. I went through 4 different switches, a Carling, an Alpha, those cheap Taiwaneese switches that Smallbearelec sells, and still there's no cure. I also tried sonnecting it in the fasion of old MXR pedals, where input is always connected to the board input and only output is switched between the output of the board and the input jack(straight signal). In this connection, the pops are still present both when turning pedal on and when turning it off. I tried a battery and a power supply. It doesn't currently has an indicator LED, so it's not the surge caused by millenium bypass.
I am out of ideas. Anyone who may know how to fix it, please help.
Thanks in advance.

[jimbob]

I hope this isnt a normal problem. Im starting my Ross Phaser tonight.. Already etched the board- just needs drilled.

[Fret Wire]

On the input side, you could have a bad cap: 100pf or .01uf. A bad 1uf on the output side could do the same. It doesn't seem like D1 or D2 would raise hell with switching. Maybe wiring it up with a grounded input, hi-gain style, may help. Maybe double ckeck the stereo input jack for a cold joint, and good spring tension.

[ninoman123]

Pops are caused by leaky capacitors a lot. They arent blocking the DC that they should be so some DC is getting places it shouldnt be. I suggest replacing the input/output caps.

[Fret Wire]

I hope this isnt a normal problem. Im starting my Ross Phaser tonight.. Already etched the board- just needs drilled.

Me too. I decided to expand my phaser horizons past the Phase 90 and try the Ross. I even scored an orange model fairly cheap to compare schematics and sound against my build. I fixed a PH-1 for someone, and wasn't impressed. I scored a nice condition PH-1r cheap, and it's much better than the regular PH-1. So far, my diy Phase 90 is still my fave. We'll soon see.

[R.G.]

Popping on switching is

always, always, always, always, always, always, always, always, always

caused by a sudden shift in DC levels when you switch.

This can be caused by
(1) capacitor leakage by normal capcitors, for which pulldown resistors are a cure.
(2) abnormally large leakage by capacitors, for which pulldown resistors can't pull the large leakage to ground.
(3) a sudden shift in the ground or power supply level in the pedal when switching; this is usually a problem caused by wiring the LED so that its ground current is on the same wire as the circuit's; there are other causes though
(4) a bad/leaky/poorly timed footswitch
(5) capacitive coupling of a sudden switch transient (like that from the 7V swing on the LED switching wire) into a signal wire or circuit component. This requires a high impedance point, like a JFET, MOSFET, JFET/MOSFET input opamp, bootstrapped input, or tube to couple effectively, plus some bad wiring.
(6) a circuit construction or wiring error that makes the circuit itself do a level jump when the footswitch is switched.

[jrc4558]

Thank you gentlemen!
I tried replacing the in-out capacitors. No effect. Off to work now, will try more in the evening.