SWITCH POP/PULL DOWN RESISTOR

[pachi2007]

Hi
I was wondering if it´s ok to solder the resistors on the in/out jacks? 1Meg from tip to sleeve.
Would be enough just one resistor soldered on the out jack?
Thank you very much

[rullywowr]

I don't think this would be very effective.  When the PCB is disconnected from your bypass signal, the 1M pull down is designed to help bleed off any residual voltages in the circuit. By putting it on your jacks, it will be disconnected from the circuit while bypassed and not helping you. Plus it would be affecting your bypass signal at all times.

[stecykmi]

ya, it should go after the switch to make sure the circuit input is grounded.

but you could certainly try it your way first, it won't hurt anything. 1Meg is huge so it won't attenuate your signal very much.

[brucer]

I'd love to hear more on this point.  I'm a novice, with just enough knowledge to get myself into trouble.  I've been putting a 1M resistor from tip-to-sleeve on my in/out jacks to combat "pop", but I've had mixed results.   I've read that they should be put on the input and output caps instead, but haven't felt confident enough that I could: 1) correctly ID the input and output caps and 2) figure out how to place a resistor on them (e.g. from the cap's cathode to ground or ...?).  a definitive "how-to combat pop" for newbie's would be appreciated, if that's possible.  Sorry if it's already been posted and I missed it.

[rullywowr]

The idea of a pull down resistor is to drain the residual charge out of the effect when bypassed. It is usually a 1m or higher resistor with one side on fx input and other to ground. If you put it on the jack it does no good because when the effect is bypassed, charge has no where to drain to. Therefore when you switch the effect back on, the voltage differential makes a pop.

Keep in mind that it may not always be the absence of a pull down resistor causing pop. It can be the led when activated as well. Great info regarding the subject is by amz  - google amz popping led for lots of info.

[brucer]

Thanks Ben for the explanation and guidance.  So, just to clarify ... the 1M resistor should go from the PCB "In" pad to ground?   On the Madbean wiring diagram, would the correct ground connection point for the resistor be the sleeve of the input jack or the network of ground connections on the 3PDT switch?

Also, case in point for your caution that pop may not always be the absence of a pull down resistor, I've been re-flowing solder, re-boxing and trying a bunch of grounding strategies to get rid of some horrendous pop in a tremolo build, only to find out tonight that it was a poorly seated transistor!  Solved now though!

Hope this helps the original poster too.

Thanks again.

[pachi2007]

Thank you all.  It´s been very helpful. Thank you very much

[rullywowr]

Glad to help!

Thanks Ben for the explanation and guidance.  So, just to clarify ... the 1M resistor should go from the PCB "In" pad to ground?   On the Madbean wiring diagram, would the correct ground connection point for the resistor be the sleeve of the input jack or the network of ground connections on the 3PDT switch?

First, take a look at the schematic. Many layouts already have this resistor on the layout.  Look for a 1m right at the input going to ground. If it already has one, another won't help.  If you are adding one you can put it from the fx in to any ground point (input jack sleeve is fine).

It's cool you found that an unseated component can cause popping too.

[chromesphere]

Ive piggy backed 1m PDR's on the 3pdt lugs before (effect input to ground) and its worked fine as it is essentially the same as a normal PDR just on the 3pdt instead of on the pcb.  Another option if theres nowhere easy to access on the pcb. 

Also make sure whatever method you try works with some alligator clips first.  Obviously if you connect it incorrectly, could make matters worse.