Same pedal, different Bypass

[DJPsychic]

I just finished 2 fuzz faces, I owe all thanks to the gurus on here.

The issue I'm having, is the pedal on the LEFT bypass is slightly quieter and not as clear the other

They are both wired the same. One has the additional 9v jack (LEFT). The other (RIGHT) just has the switch and circuit board turned around inside the enclosure to for better fit.

But they are both identical circuits.

The only thing I can think that happened is LEFT pedal's bypass shorted out momentarily when the battery touched the RED jumper wire on bottom row of switch today.

Could it be a bad switch?

[idy]

I don't think there is such a thing as two identical fuzz faces... You're saying that in bypass mode one of them sounds a little muffled?

I would look at anything touching a jack or the back of a pot.

Just touching the 9v to the switch should not hurt it, but switches don't like soldering irons and often die from too much heat. But usually they fail open or intermittent.

Check jacks for corrosion and good fit... maybe something you don't notice when the fuzz is on is always muffling things.

[DJPsychic]

I don't think there is such a thing as two identical fuzz faces... You're saying that in bypass mode one of them sounds a little muffled?

I would look at anything touching a jack or the back of a pot.

Just touching the 9v to the switch should not hurt it, but switches don't like soldering irons and often die from too much heat. But usually they fail open or intermittent.

Check jacks for corrosion and good fit... maybe something you don't notice when the fuzz is on is always muffling things.

Yep exactly. It’s just slightly quieter and a bit muffled. It’s subtle but it’s there.

And for whatever reason when the battery touched that red wire on switch it did cause short...It was weird. Maybe something else moved who knows.

It is a used switch I grabbed off an old project so could be the heat.

Jacks are brand new switchcraft.

I should mention earlier, I didn’t have bypass for a moment, but fuzz would work. Now both work but bypass does  seem slightly quieter compared to bypass of other pedal.

I’ll maybe try replacing switch in the morning.

[antonis]

It might be an issue just as simple as lugs jumper wire..

[DJPsychic]

So I did a quick continuity test on the switch. Everything is working, although some spots I had be touching the very tip of the solder where tip of wire is poking out.

[antonis]

A resistance measurement, In jack tip - Out jack tip, should be more enlightening..
(in case of your DMM has a probe resistance zeroing mode, plz use it..)

[DJPsychic]

A resistance measurement, In jack tip - Out jack tip, should be more enlightening..
(in case of your DMM has a probe resistance zeroing mode, plz use it..)

Ok, how do I do this test? Sorry I’ve never done on the jacks before..

[antonis]

Set DMM on Resistance mode, 3PDT switch on bypass and place probes as below:

[DJPsychic]

Ok. Not sure which is bypass (Don’t have guitar plugged in), but on one setting nothing and another setting it seems to jump around then go back to 0

[DJPsychic]

Ok. Not sure which is bypass (Don’t have guitar plugged in), but on one setting nothing and another setting it seems to jump around then go back to 0

Edit: guitar plugged in, battery in pedal, on standby: multi meter jumps around and goes back to zero (0).

I did get it to hold at 5k once but lost it. Back to zero each time.

[antonis]

You don't need to have guitar pulgged in.. Also, no need for power on..

As long as you get zeros ohms between In & Out tips on bypass mode, something "outside" (before or after) creates the volume drop..

[DJPsychic]

You don't need to have guitar pulgged in.. Also, no need for power on..

As long as you get zeros ohms between In & Out tips on bypass mode, something "outside" (before or after) creates the volume drop..

Very cool thanks for the tip. It can really only be the switch then.

Circuit wouldn’t cause drop in bypass. Unless the added 9v jack has an effect on the input Jack it’s grounded to, It is a used one from another failed project.

That’s all I can’t think of. What do you think?

[antonis]

That might happen in case of measurable high value resistance existence between IN or OUT jack tip and GND..
(voltage dividing effect..)

It should be a good idea to take a resistance measurment between IN or OUT tip (it doesn't matter which of them, as long as they exhibit perfect short when signal bypassed) and GND..
(try it on various ground points - although Ground is Ground is Ground  - like on metal enclosure, DC jack ground, PCB ground & Battery negative pole..)

Or better, wire OUT jack sleeve (the one with green wire going to PCB) on IN jack sleeve (the one with black wire going to DC jack ground) and try it without any measurement..

[snarblinge]

if you want to troubleshoot the switch (after the measurement suggested) you have a spare set of poles you can try next.

also anything intermittent is generally cable connections, reflow solder on the switch, just to be sure.

[DJPsychic]

Yeah, I’m going to re-solder everything, hopefully that helps. The input jacks are brand new, so it has to be the switch or solders like you mentioned.

Can’t get any new switches for a while, USPS is unreliable at the moment they’ve lost 4 packages this week of mine (with a bunch of Germaniums in it  ) but understandable in the current situation I guess.

[DJPsychic]

Tried a different used switch, re-soldered connections still same issue. It’s subtle but  it’s there. I can tell by how much everything in my house rattles, it’s a great tool 

I downloaded a noise level app and pedal in question is about .6-7 dB quieter. I hooked up a loop pedal and played the same riff through each pedal individually while measuring.

It’s driving me insane 

Only options I can think are replacing jacks, and waiting for a new switch to arrive.

[antonis]

Until then, try to desolder DC jack ground and solder battery negative wire on both In & Out sleeves..

If it doesn't work, measure resistance between IN (or OUT) jack tip and White wire from lug 1 to PCB.. Then repeat measurement between IN (or OUT) jack tip and Blue wire from lug 4 to PCB..(on bypass mode, of course..)
In case you get any other value than "open", your switch needs replacement..

To get the into the point, you have to "somewhere" find a voltage dividing effect inside signal path..

[DJPsychic]

Until then, try to desolder DC jack ground and solder battery negative wire on both In & Out sleeves..

If it doesn't work, measure resistance between IN (or OUT) jack tip and White wire from lug 1 to PCB.. Then repeat measurement between IN (or OUT) jack tip and Blue wire from lug 4 to PCB..(on bypass mode, of course..)
In case you get any other value than "open", your switch needs replacement..

To get the into the point, you have to "somewhere" find a voltage dividing effect inside signal path..

Ok I will, thank you for the guidance. A couple questions:

1) I’m  only using battery at the moment, would the 9v jack still have an effect?

2) why would I need to test PCB connects? Isn’t bypass directly through switch?

[antonis]

1) GND isolation (just in case of..)

2) Of course, but we search for switch "internal" defect.. (like not complet isolation between opposing throws..)

[DJPsychic]

“Then repeat measurement between IN (or OUT) jack tip and Blue wire from lug 4 to PCB”

I don’t have blue wire form PCB to lug 4. Lug 4 is Tip of input jack.

The 2 blue wires from pcb goto VOL pot.