[NGroeneveld]

EDIT - PROBLEM SOLVED

TO ANYBODY WHO GOES ON ABOUT HOW GREAT SWITCHCRAFT SWITCHES ARE, I CAN TELL YOU NOW "DON'T BELIEVE THE HYPE"

SEE PAGE THREE

Three-way Les Paul toggle pops and crackles when I switch between pickups.

THIS PROBLEM OCCURS ONLY WHEN STRINGS ARE VIBRATING.

Wiggling the switch when strings are muted does not make any noise

I have tried three different switches - two of them are Switchcraft

I have tried three different amps - same on all of them

I have rewired all grounds to back of V pot. All the soldering looks good and does not appear to have any cold joints.

I have De-ox sprayed and buffed connection points with 1500 paper.

The mags run to a Graphtech piezo pre-amp and then to a stereo jack. Have checked all the connections there.

Bridge pickup has braided shield, neck is four wire with foil shield. Could anything be interfering with the Graphtech stuff?

I have metered between strings and where bridge ground connects to V pot - on the ohm setting it reads something and then rapidly dwindles to zero. Am I doing this right?

I've tried everything I can find on the web...

 

[greco]

I hate these mysterious electronic problems...so frustrating and time consuming.

I can't really help (other than to be supportive) but I'm putting my money on the pickups and/or associated circuits...only because you mention that ....

THIS PROBLEM OCCURS ONLY WHEN STRINGS ARE VIBRATING.

I'll be following this thread with interest.

Good Luck...Stay Sane

 

[NGroeneveld]

I tried this using leads instead of a resistor - the pop goes away, but the guitar sounds the same in all three switch positions

" The pop comes from a split-second open circuit situation when moving the switch from position to position, much the same as if you were to unplug the guitar without muting the amp. The easiest solution is to solder one lead of a resistor to the lug where the bridge pickup is soldered to the switch, and the other lead to the lug where the neck pickup is soldered. I'd try a 1 meg 1/4 watt resistor. The resistance of the new resistor is high enough that it won't effect the sound from the guitar, but low enough that it should help tame the pop.

 

[greco]

Did this switch noise just start recently "out of the blue" or has it always been an issue?

 

[mhammer]

Piezo preamps will generally assume there is only one pickup on the guitar; likely situated in the bridge. Since there is a presumption of only one pickup, there is also a presumption that there will be no pickup switching. There will also be a presumption that the input impedance of the preamp should be kept as high as possible. All of that means that the input cap of the preamp will not be terminated, so every time you switch pickups, you momentarily dosconnect the preamp and then reconnect it. On pedals, that generally leads to a pop. The solution here, from your description at least, sounds like it would be the same as for popping pedals: solder a resistor (let's say 2.2meg to 4.7meg) from the input of the preamp to ground. That will let the input cap bleed off any stored charge to ground at all times.

If you try this, let us know if it does the trick. Fingers crossed.

 

[greco]

On pedals, that generally leads to a pop. The solution here, from your description at least, sounds like it would be the same as for popping pedals: solder a resistor (let's say 2.2meg to 4.7meg) from the input of the preamp to ground. That will let the input cap bleed off any stored charge to ground at all times.

@mhammer Every time I hear the word "pop" and "switch" in the same sentence, I think of how many times you (and others) must have written this suggested solution. I hope it works in this situation and, like you, I am looking forward to knowing the result.

 

[NGroeneveld]

Piezo preamps will generally assume there is only one pickup on the guitar; likely situated in the bridge. Since there is a presumption of only one pickup, there is also a presumption that there will be no pickup switching. There will also be a presumption that the input impedance of the preamp should be kept as high as possible. All of that means that the input cap of the preamp will not be terminated, so every time you switch pickups, you momentarily dosconnect the preamp and then reconnect it. On pedals, that generally leads to a pop. The solution here, from your description at least, sounds like it would be the same as for popping pedals: solder a resistor (let's say 2.2meg to 4.7meg) from the input of the preamp to ground. That will let the input cap bleed off any stored charge to ground at all times.

If you try this, let us know if it does the trick. Fingers crossed.

Thanks I will try that - if I can get the resistor. What should the wattage be on the resistor? quarter? half? I just talked to a guy at an electronic outlet - he said to try a cap rather than a resistor across the neck and bridge lugs on the switch.

 

[NGroeneveld]

Did this switch noise just start recently "out of the blue" or has it always been an issue?

new wiring situation

 

[NGroeneveld]

Piezo preamps will generally assume there is only one pickup on the guitar; likely situated in the bridge. Since there is a presumption of only one pickup, there is also a presumption that there will be no pickup switching. There will also be a presumption that the input impedance of the preamp should be kept as high as possible. All of that means that the input cap of the preamp will not be terminated, so every time you switch pickups, you momentarily dosconnect the preamp and then reconnect it. On pedals, that generally leads to a pop. The solution here, from your description at least, sounds like it would be the same as for popping pedals: solder a resistor (let's say 2.2meg to 4.7meg) from the input of the preamp to ground. That will let the input cap bleed off any stored charge to ground at all times.

If you try this, let us know if it does the trick. Fingers crossed.

I'm assuming that the input wire is the one going out from the V pot to the preamp, and the resistor will be grounded onto the back of the V pot

 

[mhammer]

Thanks I will try that - if I can get the resistor. What should the wattage be on the resistor? quarter? half? I just talked to a guy at an electronic outlet - he said to try a cap rather than a resistor across the neck and bridge lugs on the switch.

If a 1/8w resistor works in the pedals you feed your guitar to, then it will clearly work here. Higher wattage resistors certainly won't work any worse, but just aren't necessary, and take up more room. But if you can't score 1/8w, 1.4w or 1/2w will do fine.

And yes, wherever the lead from the volume pot to the preamp lands IS the input.

However, now that you bring it up, I may have spoken too soon. My "diagnosis and prescription" is based on some assumptions about where in the sequence of things your pickup selector switch is located. Please indicate which of these scenarios is the correct one:
a) pickups->selector->controls->preamp->output-jack
b) pickups->controls->selector->preamp->output-jack
c) pickups->selector->preamp->controls->output-jack

B and C would yield the popping I described, but A would not, and would require a different cure.

 

[NGroeneveld]

If a 1/8w resistor works in the pedals you feed your guitar to, then it will clearly work here. Higher wattage resistors certainly won't work any worse, but just aren't necessary, and take up more room. But if you can't score 1/8w, 1.4w or 1/2w will do fine.

And yes, wherever the lead from the volume pot to the preamp lands IS the input.

However, now that you bring it up, I may have spoken too soon. My "diagnosis and prescription" is based on some assumptions about where in the sequence of things your pickup selector switch is located. Please indicate which of these scenarios is the correct one:
a) pickups->selector->controls->preamp->output-jack
b) pickups->controls->selector->preamp->output-jack
c) pickups->selector->preamp->controls->output-jack

B and C would yield the popping I described, but A would not, and would require a different cure.

The pickup leads go to the 3 way switch. like this

2 Humbuckers/3-Way Toggle Switch/1 Volume/1 Tone

 

[NGroeneveld]

If a 1/8w resistor works in the pedals you feed your guitar to, then it will clearly work here. Higher wattage resistors certainly won't work any worse, but just aren't necessary, and take up more room. But if you can't score 1/8w, 1.4w or 1/2w will do fine.

And yes, wherever the lead from the volume pot to the preamp lands IS the input.

However, now that you bring it up, I may have spoken too soon. My "diagnosis and prescription" is based on some assumptions about where in the sequence of things your pickup selector switch is located. Please indicate which of these scenarios is the correct one:
a) pickups->selector->controls->preamp->output-jack
b) pickups->controls->selector->preamp->output-jack
c) pickups->selector->preamp->controls->output-jack

B and C would yield the popping I described, but A would not, and would require a different cure.

The pickups go to the 3 way switch, then to the volume pot, then the input goes to the preamp and then out to the stereo jack.

 

[mhammer]

In which case, kindly disregard all my blathering earlier. If the volume pot is hardwired to the input of the preamp, then the input cap on the preamp has a bleed-off path to ground, and is not the source of your problem. Sorry for the detour. Ah well, I tried.

 

[NGroeneveld]

In which case, kindly disregard all my blathering earlier. If the volume pot is hardwired to the input of the preamp, then the input cap on the preamp has a bleed-off path to ground, and is not the source of your problem. Sorry for the detour. Ah well, I tried.

I'll try the resistor or cap across the neck and bridge lugs

 

[greco]

new wiring situation

What wiring changes did you make from the previous?

 

[NGroeneveld]

In which case, kindly disregard all my blathering earlier. If the volume pot is hardwired to the input of the preamp, then the input cap on the preamp has a bleed-off path to ground, and is not the source of your problem. Sorry for the detour. Ah well, I tried.

Thanks for your time anyway

 

[NGroeneveld]

What wiring changes did you make from the previous?

Guitar originally had one neck pickup - I added a bridge pickup, and a Graphtech piezo

 

[NGroeneveld]

bridging the neck and bridge lugs with a one meg resistor did not work - guess I will have to take it to an expert

 

[BSTheTech]

Get rid of the piezo and see if it stops. I'm guessing its still sending a signal.

 

[NGroeneveld]

Get rid of the piezo and see if it stops. I'm guessing its still sending a signal.

Well - I'll be away for a week so nothing is going to get done on it for a while. Will disconnect the whole piezo system and wire it up with mags only and see what happens