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This might help: https://www.mrblackpedals.com/blogs/straight-jive/6629778-what-really-causes-switch-pop

In your experience: do you think a pop noise could be also a consequence of the PCB design? Using the power and ground planes, if the traces fragment too much the continuity of these planes, a pop noise could be induced when switching on the pedal the first time. Could it be possible?

Sorry for the hijack. Which set is the third set?


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I meant the third column of pins on the 3pdt, left unused if the switch is wired as Millennium Bypass

I'm thinking its goes with the "Many ways to skin a cat" term.

Millennium bypass used to be really popular when 3PDT blues were $8-$10 a piece.

Indeed... that's the reason why using a 3pdt wired as a Millennium Bypass seems like a non sense to me... unless the Millennium Bypass has some "special feature" worth of preferring it over other wiring schemes...
But if so, why don't we see many more Millennium Bypass around?

I would assume it's because they saw other people doing it too.


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All joking aside, I think it's really true: altough it's unusual to see a Millennium Bypass with a 3pdt, they can also use the third set of pins (left unused on the 3pdt) to ground the input... But they don't. Why?

To eliminate pop noise from the LED turning on.
Quality 3PDTs are cheaper than good DPDT footswitches.

Ok, but... why using the Millenium Bypass?
If the pop noise is due to the LED turning on, why there aren't more Millennium Bypass in pedals (like wampler...)?

I would assume it's because they saw other people doing it too.


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BOOM! shots fired. LOL

  LOL

Hello guys,
do you know why JHS uses a 3pdt switch in many drive pedals (like the moonshine, charlie brown, morning glory...) wired as a millenium bypass?
Is there any reason for that?
Does the millennium bypass reduces the "pop" noise?

[/quote]
Actually, I don't know. My gut says no. I'd have to look that up (or maybe we both should!)
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I've done some simulations and I had these results:

1) LC network filtering: if you have a very little spike in the supply voltage (like 0,01volts) you can see the output voltage swinging and after a while it return steady.

2) RC network filtering: if you have a spike of the same amount (0,01volts) the output voltage is just a little perturbed but it stays pretty much close to the nominal value of 9v.

I should say that, regarding the ripple reduction, the LC is not an improvement compared to an RC... what do you think?

Sure, I'm searching in my engineering books 

Two reasons -
Inductors are more efficient than resistors - they don't dissipate heat like resistors.
Inductors give you a two-pole filter instead of the one-pole filter you get with resistors.

To find out more look up LC vs RC filtering

Last question... does a second order low pass filter like this minimize ripple on the DC power more than a simple first order low pass would do?

Or maybe I should ask: "does a low pass filter affect the stability of the DC power minimizing the ripples? Or it just cut off the (noisy) high freq. content of the DC?" 

Two reasons -
Inductors are more efficient than resistors - they don't dissipate heat like resistors.
Inductors give you a two-pole filter instead of the one-pole filter you get with resistors.

To find out more look up LC vs RC filtering

Thank you very much!! 

Hello guys, can someone explain me what are the differences (and advantages) of using the inductor (1mH) in the power supply filtering section, rather than a normal resistor?

Thanks

I've had that too, with a pedal in one situation but could not reconstruct it later. I guess switch pop is a complex issue with a multitude of potential causes.

Agreed. That's why I did this post, to list some of the causes (and their solutions) I've figured out.
The clickless true bypass relay system that mutes the signal (for like 40ms) is effective (you don't hear a pop) but actually I find it to be annoying and somewhat unnatural.
Muting the signal is like "taking a painkiller", you don't feel the pain, but you're not treating the desease... 

...Not because I have tested the audible differences between all contenders, but just because it makes me feel good  ...

Bottom line: don't worry too much, check schematics/BOM to see what the designer calls for, and experiment if you like with alternatives (he, this is DIY after all).

Eheh I think you're right! 

The only problems with popping have been when using relay switching circuits ... especially those that are said to eliminate popping 

I've noticed that too... rather paradoxical isn't it?



I've also noticed a behavior that I cannot explain:
A (quite high gain) overdrive I've built pop ONLY the first time after I plug the power supply. The second time if there's a pop, it's really smaller than the first one. Why??