Bad mic shock

[Ron Kimball]

Re: Bad mic shock

I'm wondering if he was using vintage guitar amp...

Probably not something yous big fish have to deal with - but I carry a grounding clip on 8 feet of green wire that has a three prong plug on it (ground prong used only) for the occasional vintage amp that I encounter. It gets clipped on the shell on the instrument cable at the amp after I set the polarity correctly. Not perfect but if someone wants to run an all original 60's amp damned if I'm gonna deprive them of using it and me of hearing it - can't say I've run into anyone running one that wasn't a monster player .

 

[Mike Sokol]

Re: Bad mic shock

I have several of these. Sears has them or you can order them online. They really work. Fluke Volt Alert

I've been pioneering the use of NCVT (Non Contact Voltage Testers) to test for improper gear grounding for several years. Here's a video of me using one to detect a hot-skin voltage on a model of an RV. How-To RV Hot-Skin Shock Demonstration - YouTube I'm going to do a new video in a few weeks showing how it works the same way to find voltage on a guitar or microphone. It's the best $25 you'll ever spend, and a lot safer than touching a piece of sound gear to "check" for voltage. I have my own crews walk around the stage with a NCVT and touch all mics and backline amps. Only takes a minute, and it's great insurance. I've had guitar players and singers walk off-stage when they felt a shock and refuse to continue the show. Guess who the promoter is pointing a finger at when that happens??? Yes, it's always the soundguys' fault!!!!

Mike Sokol
[email protected]
No Shock Zone

 

[Tim McCulloch]

Re: Bad mic shock

I've had guitar players and singers walk off-stage when they felt a shock and refuse to continue the show. Guess who the promoter is pointing a finger at when that happens??? Yes, it's always the soundguys' fault!!!!

Mike Sokol
[email protected]
No Shock Zone

One of my pet peeves is the bullshit attitude that the artist's equipment is never at fault. Old batteries in an acoustic guitar? Gotta be the production company... Popping on an input? Gotta be the PA system - couldn't possibly be the artist's ME turning on +48 to a wireless receiver (this happened recently).

As providers it seems we are required to do all kinds of shit to prove OUR gear is right, but until then the performer's gear is not to be considered suspect. BULLSHIT. I've got a long story about a BE for a band named for a deadly biological poison that I'll write up as a blog post sometime, but the short version is that he was convinced one side of our PA was blown... and after 2 hours of trying to demonstrate the problem was on his end, we eventually demonstrated to his boss that the problems were caused by the BE's direct physical actions and were not failures of our system, components or personnel. And I hope that he is still living it down...

 

[Mike Sokol]

Re: Bad mic shock

One of my pet peeves is the bullshit attitude that the artist's equipment is never at fault.

'
The beauty of using a NCVT (Non Contact Voltage Tester) like a Fluke VoltAlert to test for hot-grounds on stage is that you don't need to measure "between" two pieces of gear to find out what's "hot". Since a NCVT is capacitively coupling to the earth below, it doesn't require an actual connection to earth ground like a standard voltmeter. So it's really obvious when you point it at a guitar amp with a "hot" chassis and it starts beeping. In fact, if the guitar amp chassis is sitting at 120 volts (easily possible) than a standard 90 to 1,000 volt VoltAlert will trigger from nearly a foot away from the amp. This allows you to point out to the talent that their guitar amp chassis (and any guitar plugged into it) is dangerously electrified.

And if you indeed have a floated ground on your entire PA system (very possible plugged into ungrounded genny power or mis-wired building power) then a VoltAlert will trigger anywhere close to any of the mics on stage. It's a really quick and obvious safety check that takes only seconds to perform.

Yup... I'll do a video of this when I get back from a gig this weekend.

Mike Sokol

 

[Ron Kimball]

Re: Bad mic shock

Hey, is the Klein Tools NCVT-2 Dual Range any good?

 

[Mike Sokol]

Re: Bad mic shock

Hey, is the Klein Tools NCVT-2 Dual Range any good?

Klein sent me a pair of them last month to experiment with, and while the dual range idea seems good on paper, I feel it's really too complicated for the average "joe" to operate. That's because there's a single button you have to push in various sequences to set the range to high or low volts, and a pair of multi-colored lights that indicate presence of low (5 volts) or high (40 volts) when on a large charged surface like a guitar amp. There's no clear labeling on the tester itself, so I have to keep referring to the printed directions on how to get it into high or low range, then I can't remember how to get it into high range the next week. It's a good idea but needs a simpler "operating system" and foolproof indicator as to what voltage it's indicating. Guess I should do a video review of that as well.

Mike Sokol
[email protected]
No Shock Zone

 

[Ron Kimball]

Re: Bad mic shock

Well, as it was under 19 bux on fleaBay I just got in one of the dual range ones. To properly test it I didn't read the instructions first (who does that anyways?) but found it easy to use and switch back and forth to the different ranges - but then again I'm not your average Joe nor are most or yous guys. I did miss how you can switch off the beeping but that's probably not something you need to do in our usage - the beeping is probably a help to convince the potential victim that their prize POS amp is gonna kill them :twisted: .

For reference:
Push the button 1/2 second to turn it on or off.
Push the button 2 seconds when on to change the range from "dual" to "high only".
Push the button 2 seconds when off to turn the beeper on or off.
That's it!

BTW I picked up a blade retention tester a couple months back too so I'm doing good putting together a great gig bag 8)~~.

 

[Mike Sokol]

Re: Bad mic shock

the beeping is probably a help to convince the potential victim that their prize POS amp is gonna kill them :twisted: .

I have at least six different brands/models of NCVT's and always leave the beeper on for just that reason. Plus at least one of them (an Amprobe) has a built in "shaker" so it vibrates in your hand in addition to blinking a very bright light and sounding a very loud beeper. What you'll find with any of these testers is that since they were designed for testing potential on the surface area of a wire from less than an inch, when you get them close to a large "hot" surface such as a guitar amp, they'll BEEP from many inches away. Something as large as a "hot" mixing console chassis will make them light up from a foot or more away. The first time I tried one on an RV with a "hot-skin" condition my Fluke VoltAlert would beep from 18 inches away, and the video guy shooting the demonstration said "holy s**t" and nearly dropped his camera when he saw it light up from at far away. I also do a demonstration in my No~Shock~Zone seminar where I electrify the ground of an entire (small) PA system with a Mackie mixer, powered speaker, and a few microphones. I generally have a powered monitor on the floor close to my students, and start off with 40 volts AC on the ground, which will cause a standard sensitivity (90 to 1,000 volts) to beep on contact. When I then raise the demonstration voltage to 80 volts the NCVT will light up from a few inches away from the speaker at their feet, and the front row looks nervous. Finally, I crank up the transformer to 120 volts AC, and the entire front row pulls their feet away from the floor monitor and everyone gasps when I show the NCVT beeping from a foot away of the mixing console.

but then again I'm not your average Joe

I'm sure that true for many pro sound technicians (and I'm not being condescending), but the fact is most casual users will be confused by the idea of different color blinking lights and sensitivity controls that need to be "calibrated" to the situation. I'm fishing for a grant that would allow me to teach NoShockZone seminars at music schools around the country and give away a bunch of NCVT's to students at each location. But it's gonna be a simple tester since they'll probably throw it in their guitar case and need something really simple to operate.

It would be great if somebody made a NCVT that not only beeped, but included a little digital meter to show potential voltage. Of course it wouldn't be that accurate, but it would give a range of potential "hot-ground" voltages.

BTW I picked up a blade retention tester a couple months back too so I'm doing good putting together a great gig bag 8)~~.

What brand retention tester did you get?

 

[Ron Kimball]

Re: Bad mic shock

On low range this NCVT is VERY sensitive. I figure that beeping from farther away will be more convincing (AKA panic inspiring).

What brand retention tester did you get?

Woodhead 1760 , I stole it off fleaBay for $23.50 .

 

[Mike Sokol]

Re: Bad mic shock

On low range this NCVT is VERY sensitive. I figure that beeping from farther away will be more convincing (AKA panic inspiring).
Woodhead 1760 , I stole it off fleaBay for $23.50 .

Here's a pic of me using a standard high-voltage Fluke VoltAlert (rated for 90 to 1,000) volts to detect a mic biased to 120-volts AC from 6 inches away. Even the high-voltage VoltAlert will detect a mic or guitar amp with as little as 40-volts AC on the chassis even though it's rated down to 90 volts for testing outlets. And I've personally found that the low-voltage NCVTs (high-sensitivity) will often false trigger just walking around a normal stage. But perhaps the two-level tester from Klein is a reasonable compromise since you can set it on standard sensitivity for general checking around stage, and high sensitivity (low-voltage) for more thorough tests. However, once I see a beep from a VoltAlert, that makes me get out my trusty digital meter and find the actual chassis voltage to ground. That's really the gold standard test.

And yes, if you come across a guitar amp chassis sitting at 120-volts, any of these testers will scream bloody murder from a foot or more away. Guaranteed to get the musician's attention.