Idea for a simple box that prevents microphone shocks, reasonable?

[Paul Marossy]

http://www.audiogear.com/cgi-bin/shopper.cgi?key=RPCOISOBLOX&preadd=action

Bingo Sir H C! At that price, it's simpler to just buy it instead of trying to make it. You wouldn't really save any money building one yourself.

[soulsonic]

Wow, that's cheap. Go for it! The frequency response probably stinks, but it'll get the job done. I believe ProCo has one too. Yes, it's called the IT-1. I'm sure it's very reasonably priced as well.

[Paul Marossy]

The frequency response probably stinks, but it'll get the job done.

It shouldn't, it has a 600ohm/600ohm transformer in it, which is what is required. It's like connecting two mic cables together, but electrically isolating them.

[R.G.]

.... full body condom...

[soulsonic]

The frequency response probably stinks, but it'll get the job done.

It shouldn't, it has a 600ohm/600ohm transformer in it, which is what is required. It's like connecting two mic cables together, but electrically isolating them.

In a perfect world maybe! But the laws of physics are against us!

[magikker]

i was just listening to Travis on NPR's live concert series, and the singer got shocked on the mouth during the show... Stopped the show and everything... Said he almost got knocked out one time... made me think of how nice it would be to have this. 

[Sir H C]

Wait, Iknow what club the Travis show would have been at.  I know the PA there is okay, so it had to be his amp, or the carpet on the stage giving static electricity zap.  This is one great reason to go wireless.

[Paul Marossy]

In a perfect world maybe! But the laws of physics are against us!

If you keep cable lengths to a minimum, I seriously doubt you'll hear anything noticeable (talking about the average person, not someone who can hear a mosquito fart at 30kHz).

[Sir H C]

In a perfect world maybe! But the laws of physics are against us!

If you keep cable lengths to a minimum, I seriously doubt you'll hear anything noticeable (talking about the average person, not someone who can hear a mosquito fart at 30kHz).

More importantly it can usually be compensated for.  If it is a problem, then you have to work towards finding the root cause and correcting the problem but the isolator is a great quick fix.

[Processaurus]

Thanks for the thoughts, sounds like both isolation transformers and windscreen (a really reasonable thing to have in you guitar case) are ways to not get shocked, and sorry if I missed anybody's response, but is there anything actually wrong with the original microphone ground switching box idea?

I like the second idea better than the box that connects PA and amp ground (current through the XLR cables shield seems questionable), the box that lifts the mic ground from the box to the PA, and sends it to the amp ground.  The only strange thing for the mic signal arriving at the PA is that the mic signal is referenced to a ground with a different DC potential as the PA, would this do anything bad, it seems like the first coupling cap on the PA input would remove any DC from what the PA mic input is seeing.

[soulsonic]

There's a very good chance it would have a bad hum.

[Paul Marossy]

There's a very good chance it would have a bad hum.

Yeah, probably so. Darn ground loops.... mutter, mutter, grumble, grumble. 

[Processaurus]

There's a very good chance it would have a bad hum.

Only time I've had a legitimately raging groundloop was when I plugged a daisy chain of the bassist's into a pedal of mine to steal some power, bass amp was plugged into one side of the garage, guitar amp into the other side, HHUUUMMM!  We got out the extension cord and plugged them into the same outlet and it was fine.  Thinking about it, that would probably mean the first (shorting mic ground and guitar ground) idea would be likely to have the same problem.  But the second, ground swapping idea?  Would that hum?

[R.G.]

I hit this issue a few times in my monthly column in Premier Guitar, which used to be Musician's Hotline.

You guys build effects, right? You have a DMM right?

Ever think of *measuring* the AC - shoot, DC too - voltage between your guitar strings and the mike? That protects you against everything except replugging and wiring failures during the show.

Here's another one - how about taking the AC power plug tester you have so thoughtfully brought along to the gig and ...testing... the AC power outlets for whether they're wired correctly, and whether the safety ground is high impedance or not? A miswired house outlet can kill your own personal self dead. Sure gigs are hard to get, but they're not worth dying for.

You step up on stage for pay, you're a professional. Act like one - which includes doing enough checking the landscape out and knowing you'll survive the gig.

[runmikeyrun]

I just use a thick foam screen cover on my mic.

me too.  keeps me from getting shocks and chipping my teeth, which my dentist said would require caps if he had to grind out the dings one more time    I've been shocked a few times, and it sucks, feels like needles being jammed into your lips and fingertips.

I carry a yellow tester from home depot with me to shows, it was like $5.  Test my outlets every time.  This doesn't give you 100% coverage because the pa can still be at different potential or live but at least you know you won't be killed when you pick up your guitar.    I was at a show in the basement of a local craphole once when the breaker blew, the guy said "wait a minute" and went and stood in a small puddle to flip the breaker back on.  This was the SOUND GUY!  Not all of them know what the heck they are doing.  Some places always have problems and the sound guys they just know what to touch and not to touch when setting up not realizing there is a problem.

Not an option for everyone, but i lifted the string ground on my bass as well and to kill the noise I wrapped my soapbars in foil and grounded that to the jack ground, then spray painted the foil black and covered with thin self adhesive clear tape so i couldn't rub it off.  Not really an option on regular guitar pickups though.

the isolation transformer would work well.  Might fit in the cavity if you get a super small one.  You could even stick it in a small box with input-output jacks.