Popping noise when switching

[Selfish Shepherd]

First of all, Hi all.
I'm new here and new as well to the world of electronics and DIY.

I've installed a booster on my axe. an EMG AB.
worked great and all, but I was concerned about the whole battery issue.
so I've installed a 3PDT mini toggle.
after a couple of hours of hassling and re-doing the whole thing I have managed to gain what I intended.
which is bypassing the booster and the battery when not in use.
thus making it possible to leave the guitar plugged with a PL while not draining the battery.
here is a poor schematic of how I wired the 3PDT:


the wire from sleeve is connected to a stereo input jack.
so the negative terminal from the battery closes circuit with the ground when a PL is inserted. just like in any stomp-box.

now there is a popping sound when switching between modes.
this is caused by the negative terminal closing and opening circuit.
while the battery is disconnected, there is no popping sound whatsoever.

Thanx for reading this post so far, and I hope to be a contributing source to this forum as well as a big learner.

[52 Bill]

Welcome to the place.

Because you have wired the switch to turn on and off the battery supply to the preamp, you are hearing the sound of the circuit powering up and powering down whenever you flip the switch. I don't know if there is any way to prevent this.

[Selfish Shepherd]

Welcome to the place.

Because you have wired the switch to turn on and off the battery supply to the preamp, you are hearing the sound of the circuit powering up and powering down whenever you flip the switch. I don't know if there is any way to prevent this.

thanx for the reply..
there must be some kind of way to do it.
otherwise, all stomp boxes would do the same aren't they?

[52 Bill]

thanx for the reply..
there must be some kind of way to do it.
otherwise, all stomp boxes would do the same aren't they?

Well, almost all of the stomp boxes that I know of leave the power turned on all of the time that there is a plug in the input jack.

[Leo_Gnardo]

What 52 Bill said.

To make it perfectly clear, you will have to leave your booster circuit powered up (as long as there's a plug inserted into the guitar's output jack) regardless of whether you select bypass or boosted. Try it & see if the popping noise doesn't diminish almost completely. Should take a couple minutes...

[Selfish Shepherd]

well that defies the whole purpose.
the whole entire purpose was to save on battery power while not using the booster.
I have a fix for it, but it's not bulletproof.
I have a killswitch installed, momentary short circuit between hot and ground.
by pressing the killswitch and switching between modes, the pop isn't heard.
but a situation of switching the mini toggle by mistake during a gig might still occur.

[Leo_Gnardo]

All this, to save a little battery power.

There is no "Northwest Passage" here, no magic way of making it work the way you want. You made your special switch and found out why it isn't done that way. If it were possible, wouldn't hundreds of manufacturers of stomp boxes and guitars already be doing it?

How much current does that booster draw from the battery anyway? I've seen some that use practically no current at all, and a battery can last years in those guitars - as long as they're unplugged when not being played - disconnecting the battery at the output jack as normally done.

[Mark Hammer]

One key question is whether you know what the actual current draw of your preamp is.

I'll note that in many instances, the current draw of simple onboard JFET preamps is 1ma and often less. It is low enough that a fresh cheap battery can last for 5-6 months, easily. And that is under conditions where the preamp is on and drawing current for as long as there is a plug inserted into the output jack.

Keep in mind that companies like EMG make a point of designing preamps that draw negligible current, because their sales wouldn't be very sustainable if users kept complaining abuot screw holes in the body getting stripped for constant battery replacement.

If you are concerned about battery drain, then I suggest you consider installing a battery compartment door for easy replacement, or else installing a jack and corresponding circuit for plugging in a charger and recharging an onboard rechargeable cell.

[eschertron]

I have the Afterburner installed on a guitar and, yes, I have to remember to pull the cord out when I walk away from the guitar. If your concern is that you don't want the AB to buffer your signal when not using the unit, then I'd say you've achieved that with the bypass switch. I'll agree with the other posters that battery drain should not be an issue. I've got a bass and an acoustic with active onboard electronics, and I've gone months (years?) without changing batteries.

The switch you've installed is your fail-safe for the time when the battery is drained during a gig.

[52 Bill]

According to the spec sheet, the After Burner draws 980 microamps of current and has a rated battery life of 250 hours.

You could always go with an outboard power supply and a 3 conductor cable to sort of phantom power it.

[Selfish Shepherd]

exactly. first of all I wanted it to be a fail-safe. it's a real bummer to get stranded because you forgot how long it was since you've replaced the battery and decided to risk it.
as for bypassing in order to not buffer the signal, I've found it strange today when I was playing. the AB added some high end. I really thought it would degrade the signal as the buffer is in it's off mode, but no. strange.
as for the battery draining issue. I find myself lazy at times and the ability to not remove the cable really is great for me. since I'm oftentimes playing at home and put the guitar aside for a couple of minuets or an hour or more. depends on my mood and the current events running around. that way the simple switch allows me to rest my mind easy as for the battery.