Not to beat a 'dead horse' or anything but I was curious...

[Philippe]

The other day my ordinarily quiet (true-bypass) pedals were popping like Orville Redenbacher when engaged & dis-engaged. I also noticed that the 5-way pick-up selector on my Stratocaster was crackling whenever I changed positions. Today, everything is fine.

I recall an article by RG Keen discussing both the internal & external sources of effects popping. I measured (via DMM) for any +0V in each of the input/output jacks (with the by-pass off) & they all read 0V, pretty much eliminating the pulldown resistors/LED current/excessively leaky capacitors as causal factors.

So my question is...what are the 'outside sources' that can cause this kind of occurence? There are no flourescent lights, power lines, RF, radiation etc. in the general area where I play/practice & I don't recall any roadwork or construction taking place nearby. Did this have something to do with a fluctuation in the AC line? The amplifier runs on AC but all of the effects are powered by 9V batterries.

[brett]

Hi
was the popping only happening when switching?

There are no flourescent lights, power lines, RF, radiation etc. in the general area where I play/practice

Everywhere has lots of RF, solar and cosmic radiation.  The well-shielded buildings that physicists use for delicate experiments cost millions of $$.
cheers

[head_spaz]

Capacitor leakage current is typically very small and difficult to measure, but given time it will accumulate as it charges the capacitor to some arbitrary potential.
Even "high impedance voltmeters" will introduce some resistance when you connect it to a circuit, and that resistance tends to drain whatever leakage voltage you are trying to measure. In other words, your open circuit becomes a closed circuit once you connect the meter, and the meter discharges the miniscule potential that the capacitor has accumulated. Likewise, when you connect your open circuit to an amplifier instead, via a switch, you hear that circuit discharge as a popping noise.

Try adding some high value resistors shunted to ground, in order to drain any circuits that "go open" between switching modes.
1 Megohm is a good place to start, but keep in mind that this resistor remains "in the circuit" and is then paralleled with any circuit your switch connects it to. So in many cases, 10M might be more suitable. As always, it depending on the application.

[Lurco]

my stratswitch crackles like crazy because of gathered dust.

[Crazyyellowfox]

Grid leakage will cause that too. If it's a tube amp you're running through try swapping the preamp tube in the first gain stage for another.

[darron]

last night i too noticed true bypass pop that was large with one tube amp but not the other two tube amps....

[Paul Marossy]

Or how's this for weird? I built a clone of a pedal that was recently reverse engineered and I get a big pop using the bypass switch when it's on a common power supply, but no popping at all when it is running on a battery. I've got pulldown resistors in place, electrolytic cap on the LED and so on. I've never been confronted with this situation before, and I still don't know why the problem persists.   I'd like to get it figured out because I would like to have this pedal on my pedalboard, and I don't do batteries.

[Philippe]

"was the popping only happening when switching?"

Yes Brett...only when switching them on/off. The weird thing was that the OD was only doing it during switch-off, the booster during both on/off switching & the compressor during switch-on.  As aforementioned, everything seems to be OK now & the DMM 0V input/output readings on the boxes all measured 0V!

BTW, the only effect that seemed to be behaving itself was the Axis Face Silicon 'co-perfected' by you & Mr. Bryant!

It was the intermittant 'here today, gone tomorrow' thing that has me somewhat puzzled & I'm curious what might have caused it.

[darron]

Or how's this for weird? I built a clone of a pedal that was recently reverse engineered and I get a big pop using the bypass switch when it's on a common power supply, but no popping at all when it is running on a battery. I've got pulldown resistors in place, electrolytic cap on the LED and so on. I've never been confronted with this situation before, and I still don't know why the problem persists.   I'd like to get it figured out because I would like to have this pedal on my pedalboard, and I don't do batteries.

hmm... i've got a theory on this one that's been in my mind but i haven't really experienced it for myself recently. pop usually comes from a change of current draw then the voltage to semi-conductors etc. yeah? you do what you can about putting in correct filtering etc. in your circuit so that this has a minimal effect. on battery that can be great. however, on a common power supply you can't control what filtering other people's effects have.

i think about this when i want to switch higher current drawing items like an LFO.... i can protect my circuit from making noise, but what about the nearby fuzz/booster which runs straight off the DC with no/minimal filtering? then people will assume it's the fault of my circuit, when it is only the CAUSE (:


maybe that's not what's going on for you Paul Marossy, but maybe it's something to think about? i get a pop in my amp/circuits when i turn my power supply on when it is unplugged on the DC side! hehe.

[ayayay!]

My view is an unpopular one because it's the "Windows" reponse for everything, but there IS a reason for unplugging EVERYTHING and plugging it back in:  Static.  Cures things 9 out of 10 times. 

Every pedal plug, including the DC jacks, guitar, amp,... anything you can think of.  I've been *poisoned* by my college instructors that hammmered anti-static best practicies into me.   

Paul, did you try the pedal just guitar -> pedal -> amp w/ a dedicated isolated power supply?

[Philippe]

"there IS a reason for unplugging EVERYTHING and plugging it back in:  Static.  Cures things 9 out of 10 times. 
Every pedal plug, including the DC jacks, guitar, amp,... anything you can think of." 

*ah* We could be zeroing-in on something here...considering (as an afterthought) that in my particular situation, a full wall-to-wall carpet playing surface is involved. Is it possible that the 'player' him/herself is conducting static charges simply by moving about on the surface?

Perhaps no different than the 'door-knob' effect?

[brett]

Hi

Is it possible that the 'player' him/herself is conducting static charges simply by moving about on the surface?

Absolutely yes.  Especially if you are using a valve amp (usually half to a Megohm input impedance) or a pedal with high input impedance (anything over half a Meg).  I don't understand the attraction of those 4.7 and 10 M buffers that some people use.  Anything over 1 M is gonna suck up static and spit out clicks.
cheers

[Paul Marossy]

Hi

Is it possible that the 'player' him/herself is conducting static charges simply by moving about on the surface?

Absolutely yes.  Especially if you are using a valve amp (usually half to a Megohm input impedance) or a pedal with high input impedance (anything over half a Meg).  I don't understand the attraction of those 4.7 and 10 M buffers that some people use.  Anything over 1 M is gonna suck up static and spit out clicks.
cheers

The only amp I have tried using my problem pedal with is my old 1964 Gregory Mark X amp which has a 12AX7 input tube with a 10M to ground after the input cap. I don't know that this is part of the problem, but here is the schematic I drew for it: http://www.diyguitarist.com/PDF_Files/MarkXSchemR1.pdf

Paul, did you try the pedal just guitar -> pedal -> amp w/ a dedicated isolated power supply?

No, I only tried it straight into the amp with a battery and on my pedalboard with a common power supply. No pops when it's operating on battery power only in either scenario. 

Or how's this for weird? I built a clone of a pedal that was recently reverse engineered and I get a big pop using the bypass switch when it's on a common power supply, but no popping at all when it is running on a battery. I've got pulldown resistors in place, electrolytic cap on the LED and so on. I've never been confronted with this situation before, and I still don't know why the problem persists.   I'd like to get it figured out because I would like to have this pedal on my pedalboard, and I don't do batteries.

hmm... i've got a theory on this one that's been in my mind but i haven't really experienced it for myself recently. pop usually comes from a change of current draw then the voltage to semi-conductors etc. yeah? you do what you can about putting in correct filtering etc. in your circuit so that this has a minimal effect. on battery that can be great. however, on a common power supply you can't control what filtering other people's effects have.

i think about this when i want to switch higher current drawing items like an LFO.... i can protect my circuit from making noise, but what about the nearby fuzz/booster which runs straight off the DC with no/minimal filtering? then people will assume it's the fault of my circuit, when it is only the CAUSE (:


maybe that's not what's going on for you Paul Marossy, but maybe it's something to think about? i get a pop in my amp/circuits when i turn my power supply on when it is unplugged on the DC side! hehe.

I dunno. I have put that pedal pedal aside for the moment. I need to revisit it, though...