Any remedy for kill switch popping noise?

[antigua]

I'm trying to make a Bucket Head style momentary kill switch, but the problem is, of course, that popping sound that occurs. I've Googled around but I haven't found any solutions... just questions. 

I know that with a veratone circuit 10 meg resistors are put across the various caps to prevent buildup and discharge of voltage from the caps when they are toggled in circuit. The same solution doesn't seem to apply in this case, but the cause seems to be similar. There is already resistance across the circuit, at least 250k ohms by way of the volume control, and that's a far lower value than the 10meg used for veratones. 

Does anyone have any ideas as to how this problem can be solved?

[JohnH]

Mar 26, 2017 14:18:05 GMT -5 antigua said:

I'm trying to make a Bucket Head style momentary kill switch, but the problem is, of course, that popping sound that occurs. I've Googled around but I haven't found any solutions... just questions. 

I know that with a veratone circuit 10 meg resistors are put across the various caps to prevent buildup and discharge of voltage from the caps when they are toggled in circuit. The same solution doesn't seem to apply in this case, but the cause seems to be similar. There is already resistance across the circuit, at least 250k ohms by way of the volume control, and that's a far lower value than the 10meg used for veratones. 

Does anyone have any ideas as to how this problem can be solved?

How are you wiring the kill switch? The best way is to use it to shunt the output to ground for zero sound rather than to break a comnection.

[antigua]

Mar 26, 2017 15:00:31 GMT -5 JohnH said:

Mar 26, 2017 14:18:05 GMT -5 antigua said:

I'm trying to make a Bucket Head style momentary kill switch, but the problem is, of course, that popping sound that occurs. I've Googled around but I haven't found any solutions... just questions. 

I know that with a veratone circuit 10 meg resistors are put across the various caps to prevent buildup and discharge of voltage from the caps when they are toggled in circuit. The same solution doesn't seem to apply in this case, but the cause seems to be similar. There is already resistance across the circuit, at least 250k ohms by way of the volume control, and that's a far lower value than the 10meg used for veratones. 

Does anyone have any ideas as to how this problem can be solved?

How are you wiring the kill switch? The best way is to use it to shunt the output to ground for zero sound rather than to break a comnection.

Yeah, it's a short-to-ground button.

[JohnH]

Its a puzzle then. How about a squirt of lubricated switch cleaner?

[ashcatlt]

There really isn't much you can do passively. The click or pop that you hear often has two compononents.

First is the simple fact that you're almost never going to hit that switch right when the voltage is at exactly 0. It'll be somewhere above or below and when you hit the switch it jumps (almost) instantly back to zero. It's a step function which theoretically contains all frequencies.

The other is sometimes the actual physical action of the switch. The usually don't just switch and stay there, but have a brief period where they bounce a bit. It's fast enough that it doesn't sound like a stutter, but more like a quick burst of noise - a click of pop.

The only thing you can even try to do is slow down that transition. Like, put a cap across the contacts so that the voltage ramps up and down rather than jumping instantaneously. Of course, most of the time we'd like the voltage to change as quickly as the pickups ask it to, and basically by the time the cap gets big enough to impact the click, it's killing all of the treble from your strings.

The best way to get around the problem in most circuits is to use an active switching scheme. If instead of switching the actual signal, you switch the voltage on the gate of a JFET whose source>drain channel is across the signal, you can then filter that gate voltage so that it ramps up and down and basically takes the signal with it. Rather than jumping to silence, it fades in and out. With some tweaking you can get it so those fades are too fast to hear as fades, but slow enough to not sound like a pop. If you don't have any other active stuff happening in the guitar, then I personally don't think it would be worth it, though if this is all the battery has to power, it would probably last for fricken ever.

But first! What are you plugging into? Are you positive there's not DC voltage across the cable coming from your amp or pedal or whatever is the first active stage. A leaky input cap could cause this problem, and even if it's not particularly leaky, if there isn't a pulldown resistor before that cap, it could end up floating around some and contribute to your issue.

[reTrEaD]

I don't use a kill switch but from what I've read they are notoriously poppy.

The FET switching Ash is talking about might be the solution. But before resorting to that, I would experiment with a passive solution.

Experiment #1:
Borrow the use of your tone control for this test. Remove the cap and connect the kill switch to it. If you can find a value of resistance that is low enough to kill the signal sufficiently without significant popping, that might be the solution. Use a small resistor in series with the switch.

Experiment #2:
Use the pot from the tone control in series with the signal to the output jack, after the kill switch. If you can introduce enough resistance to mitigate the popping but not so much as to significantly affect the normal signal, then that might be the solution. Permanently wire that size resistor in series with the output jack and return the tone control to normal use.

Experiment #3:
Same as experiment 2 except put the resistance between the volume wiper and the kill switch.

If any of those bear fruit ... done. If not, maybe consider the FET solution.

[antigua]

Thanks for the informative responses. I think the point about the signal being abruptly dumped in mid cycle is a problem that no passive solution can probably fix. I know that if I put a cap across it that has a value below 680pF, I'm very unlikely to hear any tonal difference, so I might give that try.  

The Buckethead sig Les Paul has passive pickups and no mention of a battery, so it does pop also apparently, and I've since read that it's less noticeable with high gain applied. Truth be told, I'll probably use it with high gain anyway, but for testing the wiring out, I was using a clean amp. You kinda need the guitar to be sustaining itself to make use of a kill button ... I was also day dreaming about making a product that involved a passive momentary kill button, but I'm thinking that the pop issue would make it seem like a crappy product. 

I've tried series resistance with the circuit in the past for other reasons, and it seems that the guitar gets noisier almost instantly, even with small amounts if series resistance. 

[sumgai]

antigua,

I tried to respond eariler (last night), but my cookie for The NutzHouse went bye-bye.... somehow.  I couldn't sign in except on a temporary basis (one page only, each page needed to be logged in again), so I'm only getting back to you now, sorry to say. (I did fix the problem by restoring from an image backup.)

In essence, John half-misspoke above. You don't break the connection and short the output, you effectively short the input of the amplifier to ground. However, by not breaking the connection between output-of-pickups and the amp, you are shorting the entire signal line to ground. At that point, it's pretty hard for any signal to be above Zero volts, hence there should be no popping caused within the guitar itself.  That's not to say that the amp, along with the cable itself, can't contribute to pops when suddenly shunted to ground, and lifted back off of ground.  Cable capacitance can and will contribute to this problem, and putting any kind of capacitor within the guitar is pretty much a non-starter.

I must confess that I am a firm believer in the ChrisK-ism that the only safe cable, and therefore also the only non-popping cable, is one that's made out of RF.  You got it, a wireless transmitter/receiver setup.  No problems of any kind, including that of Tone.  Any good setup will do the job, and as newey likes to point out, there are hacked jobs out there that use recycled cell phone batteries, which of course last a lot longer than the usual cruft found in most designs.

Just sayin', ya know....

HTH

sumgai

[piggy]

Antigua, I've been developing a passive silent kill switch for a couple years now. Just want to thank you for all the pickup work you've done for this community. It has helped me out so much!

Yesterday I wired it up and the popping noise was gone. My mind was blown because of the possibilities of the sounds I was generating. It does require quite a bit of wiring and possibly guitar body routing but I definitely think it is worth it, to me it's quite inspiring. I'll try to simplify the wiring to apply to strats and les paul in the future.

You need a least a couple of things
Momentary DPDT ON ON Normally Closed Toggle switch
Latching 4PDT ON ON toggle Normally Closed Toggle switch
Guitar with at least 2 pickups and 2 volumes

Tom Morello uses a 3 way latching toggle switch that does not kill the signal to ground. He lowers the volume of one of his pickups and toggles between them to create that tremolo effect by physically uses two fingers to toggle sound on or off.

You need to create 2 circuits with a seperate pickup and volume for each, so typically les pauls have this already, you can modify a strat for sure. My example modifies a typical hss strat.

This wiring was inspired by the jazzmaster wiring with 2 circuits. In that guitar there is a small black switch at the top that toggle betweens the rhythm circuit (bass pickup with volume) and lead circuit (bass, middle, bridge pickup, 3 way toggle switch) My kill switch replaces that jazzmaster latching toggle switch with a momentary toggle switch. This maintains the signals and doesn't get killed to ground.

The other latching 4pdt switch toggles between the circuits. So the down position and up position on kill switch can reverse. You don't need this switch but you lose the flexibility of swapping the on and off positions.

Using the volume pots and turning one pickup down creates clean sounding tremolo stutters without that annoying popping sound. Sounds especially great on clean sounds.