zapping your guitar with 9 volts

Started by diyDog, October 27, 2014, 10:19:38 AM

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diyDog

It seems like almost all stomp boxes connect the common (ground) side of the battery to the ring connection of the input stereo phone jack.  As you're plugging your guitar or other stomp box into that jack, the 9 volts of the battery, through the circuity of the box, gets momentarily applied to whatever you're plugging in, as the tip of the phone plug connector passes by the ring terminal of the input connector.  That doesn't seem polite, does it?  Am I missing something?

bool

Yeah, it's quite rude, but it's a fact of life because this way of switching the power has become a sort of a standard.

R.G.

Quote from: bool on October 27, 2014, 11:04:15 AM
Yeah, it's quite rude, but it's a fact of life because this way of switching the power has become a sort of a standard.
And a remarkably silly one.

Fortunately, the guitars don't seem to actually be damaged by it.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

bool

Well ... you could see it as "degaussing your pickups".

Like, "mang, I just degaussed my dimarzios".

Or ... zapp ... "what happened to my emgs?"

mykaitch

If you have a Blackstar you might be using a 22v psu -- I have had no trouble.
My pickups are about 2k ohms so any current is going to be very small and for not very long.
I guess with a wallwart (what a quaint name for it   :D) there is no real need to switch the psu, but I do.

PRR

> That doesn't seem polite, does it?

Oh, dear me, how rude.

Do math.

Pickup's DC resistance is about 5,000 Ohms. (Other stuff like vol-pot and internal pedal resistance will divert energy and reduce abuse; let's figure worst case.)

9V in 5,000 Ohms is 0.001,8 Amps.

9V times 0.001,8 Amps is 0.0162 Watts.

Take a 1/4 Watt 5,000 Ohm (4.7K) resistor and put it across a 9V battery for a while.

How hot does it get?

Compare the size of the 1/4W resistor to the size of the pickup.

As a rough-guess, the bigger pickup will heat-up that much less than the smaller resistor.

Flames are highly unlikely. (Even 120V across your pickup is only slow smoke.)


Flaming pickup

> "mang, I just degaussed my dimarzios".

That's a point. With modern (Alnico or better) magnets and typical pickup construction, I suspect you can't demagnetize the pickup much with one or a few dozen plug-ins.... but I am not sure about cumulative effects.

Perhaps the best counter-argument is that jack-short battery connection has been VERY common for many decades. If it killed pickups, we'd all be playing bagpipes.
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bool

Well ... well ... well.

But that's exactly why "vintage old, well played guitars" with ever-so slightly weakened pickups sound so unbelievably much better! A result of "degaussed" pickups caused from excessive cumulative plug-and-playing with a ... tubescreamer and/or a fuzzface (what else?)

Let's make this a controlled experiment and see how much time to pass for this to become an internet meme.


R.G.

Quote from: bool on October 28, 2014, 08:40:57 AM
Let's make this a controlled experiment and see how much time to pass for this to become an internet meme.
I've never been able to get excited about internet memetics. I tend to be more literal. One could easily set up a test case with a pickup, a gaussmeter, and a switch that would turn on 9V through a typical tone/volume setup for maybe one minute on, one off, and get 720 on/off cycles a day, or more than 2 years' worth of 9V "degaussing" per day and run 30 years' worth of this in two weeks. The gaussmeter would tell the tale.

... and we would know the answer without having to listen to the assorted people who got free energy, say demons or flying saucers, or had viagra-like effects from the magic degaussing process.  :icon_lol:
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

bool


mykaitch

Ah smoke! For years I understood an electric current was a flow of electrons along a conductor. The other day something happened and the smoke came out of an ic and it stopped working. I never put the smoke there so it must have been inside and got out through the crack. I connected a bit of wire across my car battery. The wire got hot, there was smoke and the wire broke. Finally I stuck a screwdriver into the electric mower motor. Sure enough, smoke came out and it stopped. The conclusion is obvious:
An electric current is a flow of smoke along a conductor -- all this rubbsih about electrons. Let the smoke out of any electronic device and it will not work, proven. (c)
I am now experimenting with a way to load smoke directly into a capacitor. No luck yet, it always escapes when I apply power. ;D

bool

Quote from: mykaitch on October 28, 2014, 12:36:56 PM
Ah smoke! ... The wife got hot, there was smoke and the wife broke. ... Sure enough, smoke came out and it stopped. ... No luck yet, it always escapes when I apply power. ;D
Mang. You are one badass mofo ladykiller.