Need help.. stopping a clicking noise when engaging a 3PDT true bypass

[syntaxera]

I know this is a common one, but I can't seem to get the LED pop out of my true bypass wiring.
have the 3PDT wired up with this diagram:  http://www.generalguitargadgets.com/diagrams/switch_lo_3pdt_ig_battery.gif

I found this thread here:   http://www.diystompboxes.com/smfforum/index.php?topic=94871.0
and this FAQ entry:  http://www.diystompboxes.com/wiki/index.php?title=Frequently_Asked_Questions_(DIY_FAQ)#POPS 



I have BC327 PNP Transistor... but I am confused to where I should be hooking it up.  As per this taken from above: 

" Use the GEO scheme for cold-switching +9V by using a PNP transistor with it's base tied through a resistor to the stereo lug on the input or output jack, and the battery minus tied directly to the board. The PNP transistor only lets +9 through when its base is pulled down by the plug in the jack, but this current does not change noticeably when the LED is started, and so any ground bounce is only through the hard-soldered milliohms of the battery lead, and is much, much smaller.
See the power supply switch in the Neutron filter at GEO or at GGG, or see the positive 9V switch in [1] for how to hook up the PNP."


Does anyone have any ideas...   should I use a different true bypass scheme? should I put the PNP transistor in line?  should I be adding pull down resistors somewhere? 

any help someone could give would be MEGA appreciated...  thanks a million

~Drew

[syntaxera]

I should also mention I have already tried putting a 1M resister between the input and output tip and grounds, as well as running 100k resistors from the input and output board to tip capacitors...   no luck with either. 

I am starting to think maybe I should try another 3PDT wiring scheme, but which one... there are so many, which one is best?

[JRB]

Well the connections don't really change with different wiring scheme's so I wouldn't bother with that. Since you already tried the 1M resistor between tip and ground all I can suggest is check if you got any DC on the in/output jacks.

And it would probably also be helpful to know what circuit you are using the switch on since it could also be some fault in the circuit it self.

[R.G.]

I know this is a common one, but I can't seem to get the LED pop out of my true bypass wiring.

1. True bypass is not a cure for switch pop. It is a way to avoid loading down your guitar when the effect is bypassed, and a way to ensure that signal can get through if the pedal has no power supply. True bypass can *cause* pops, because of the instant nature of the contacts.
2. Switch pop *may* be "LED pop" but also may not be - there are other causes. If the pedal circuit does not have pulldowns on the input and output caps, you will get pop from most true bypass schemes. If your pedal has some leakage of DC from the circuit to the switch contacts, you will get pop. If the power and ground are laid out and wired so the sudden current/no current of the LED causes a shift in the signal ground or circuit ground, you will get pop. This last is the only "LED pop".

I have BC327 PNP Transistor... but I am confused to where I should be hooking it up.  As per this taken from above: 
" Use the GEO scheme for cold-switching +9V by using a PNP transistor with it's base tied through a resistor to the stereo lug on the input or output jack, and the battery minus tied directly to the board. The PNP transistor only lets +9 through when its base is pulled down by the plug in the jack, but this current does not change noticeably when the LED is started, and so any ground bounce is only through the hard-soldered milliohms of the battery lead, and is much, much smaller.
See the power supply switch in the Neutron filter at GEO or at GGG, or see the positive 9V switch in [1] for how to hook up the PNP."

Does anyone have any ideas...   should I use a different true bypass scheme? should I put the PNP transistor in line?  should I be adding pull down resistors somewhere? 

See: http://geofex.com/circuits/+9_to_-9.htm, second picture, "Stereo Jack switching the +/-9V Supply". That's how to hook up the PNP.

[syntaxera]

2. Switch pop *may* be "LED pop" but also may not be - there are other causes. If the pedal circuit does not have pulldowns on the input and output caps, you will get pop from most true bypass schemes. If your pedal has some leakage of DC from the circuit to the switch contacts, you will get pop. If the power and ground are laid out and wired so the sudden current/no current of the LED causes a shift in the signal ground or circuit ground, you will get pop. This last is the only "LED pop".

I think it could be an LED pop, AND a DC leak.  

I am running a bunch of LEDs to a THING MODULATOR... So I had to hook up the LED power (+) directly to the LEDs before it get's to the Cap and Resistor in the circuit.   http://i42.tinypic.com/2cqbgrc.gif  <<< thing modulator          

The cap and resistor inline with (+) were bringing the voltage down too low for the LEDs (which were connected between the cap / res and pin4 of the LMC567, so I left the cap / res connected the way they were and hooked the LED Resistor / power cable up directly to the battery (+).  The LED is being turned on and off by the 3PST ground switching.  I am pretty sure this is creating a major voltage change when the effect is clicked on.  The pedal does not click when the effect is being turned off, only when it is being turned on.  

as for "See: http://geofex.com/circuits/+9_to_-9.htm, second picture, "Stereo Jack switching the +/-9V Supply". That's how to hook up the PNP."  

do you think this will do the trick?  The sleeve of the output jack is already attached to the 3PDT to complete the ground connection to the circuit.. should I just attach the transistor as well, or maybe rewire the 3PDT so that it is the power that is engaged when the pedal is stomped and not the ground.   There are so many options, I have rewired this thing so many times already... every time I fix one issue, another one pops up.   lol

[syntaxera]

of course there is always the option of dousing it in lighter fluid and setting it on fire, that way it won't make ANY popping noises at all anymore.     that will show it who's boss.   hahahaa   kidding...

but this must happen all the time, I'm surprised there aren't more threads about it... 

[artifus]

that's what down beats are for 

what circuit is it?

[syntaxera]

that's what down beats are for 

what circuit is it?

lol!  It's a THING MODULATOR ( http://i42.tinypic.com/2cqbgrc.gif ) ...  with a pretty cool lighting hookup for a LDR to control it.   So taking the LEDs out is out of the question for this one.  This circuit has been nothing but issues for me, might try the same idea with a GreenRinger next time.  BUT for now, I would love to get rid of this clicking. 

I feel like there is DC leaking, and there is a major voltage change when the ground is engaged by the 3PDT...  I JUST HAVE NO IDEA WHAT TO DO ABOUT IT..  haha

putting resistors from tip to ground had zero effect, and running 100k's from the cap/res board input and output did nothing as well.  I have tried switching the grounds on the 3PDT, that killed the bypass signal.   

For some reason I think the PNP will work, but I am still really confused as to where it would fit in my circuit...   

[cloudscapes]

Make sure your pulldowns are between in/out and ground on your PCB, and not just wired directly to your switch or your jacks. the pulldows are there to keep your circuit in check when you're bypassed, and they wouldn't work if they're just on the jacks.

[artifus]

i think you need to route the output of the 567 to ground when switching to kill the internal oscillator. i may well be wrong, though - i often am. i like finding out that i'm wrong - it usually means that i've learned something, if only that i am still an idiot.

[syntaxera]

i think you need to route the output of the 567 to ground when switching to kill the internal oscillator. i may well be wrong, though - i often am. i like finding out that i'm wrong - it usually means that i've learned something, if only that i am still an idiot.

this is very very true   well, it's V1 of this concept...  And I will have to spend more time working this issue out before V1.5.  If I know it was going to do this when it was still on the breadboard, I would have done more experimenting before doing the final build.  So much has been learned since starting it, from the difference between the LM567 and the LMC567 to better true bypass concepts.

my only wish is at the end this thing works the way it was supposed to in my head.  it is SO close right now, so many little issue have been surpassed...

of course the last, and certainly one the most important things is going wrong.  I hate pedals that change dirty, It's killer my inner child.


Anyone else have any good insight they might share with me?  ::takes aspirin, pours ice coffee:: 

[syntaxera]

Make sure your pulldowns are between in/out and ground on your PCB, and not just wired directly to your switch or your jacks. the pulldows are there to keep your circuit in check when you're bypassed, and they wouldn't work if they're just on the jacks.

I am pretty sure I have tried both ways at this point...   

I should also mention I have already tried putting a 1M resister between the input and output tip and grounds, as well as running 100k resistors from the input and output board to tip capacitors...   no luck with either. 

the "as well as running 100k resistors" part... was on the board, right off the .1uf capacitors coming from pins 2 and 3 of the LMC567 chip, and before the tip wire for both input and outputs.   It is there I ran one side of a 100k resistor and the other side to a ground...  I heard no noticeable change in the click.

[artifus]

psu filtering? big cap across + & -

[syntaxera]

psu filtering? big cap across + & -

nah, haven't tried that yet?   What sort of size cap would you suggest?  How big is "big"?

also... another thought,  since the output ring is already connected to the 3PDT make the ground connection when the cable is plugged in... 
could I add a stereo jack to the input side and use THAT ring to connect the power / transistor / resistor configuration in the GEO diagram? 

[artifus]

big is at least 100uf across your 9v input, often para with a smaller value. also, a cap across the power pins of your chip can help too.

[syntaxera]

big is at least 100uf across your 9v input, often para with a smaller value. also, a cap across the power pins of your chip can help too.

ok, great!  I will try that tomorrow and see what happens.  Thanks a bunch for taking time to try to help out.  MUCH appreciated!