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[Mark Allen]

I'm a bassist who has an unusual iem related problem at one of the churches I play at.  I have custom molds (Livewires) and, while I play for several different area churches, I only have this issue at one.  I'm getting shocked through my in-ears!

The Livewires have a quick disconnect on them that allow the molds to be removed.  From time to time, when I'm playing at this specific church, I receive mild to not-so-mild shocks near the area where the metal disconnect is near (not touching)my skin - just in front of my ear.   Since the event is not continous and it varies in intensity, it must be connected to an external cause, i.e. a compressor, lighting, etc.  The shocks aren't 'bursts', but feels like someone is touching a wire to the skin and feeding it countinuous voltage.

The iem system is an Aviom.  I run my bass through a pedalboard anchored by a Radial Bassbone.  We've tried plugging the pedalboard into different outlets around the stage. I've lifted the ground on the Bassbone.  Nothing's prevented the problem.  The effect isn't enough to prevent me from playing, but at times it's barely tolerable.

My guess is that there is some 'dirty' power on stage.  But, I don't understand why it would manifest itself this way.  No one else on stage (guitar amp, keys, etc) have any issues and, again, I don't have this problem in any other venue.

Really NOT looking for "yeah, I don't have that problem" or "just don't use your pedals" answers.   Would appreciate an informative suggestion.

Thanks!

[Hal Bissinger/COMSYSTEC]

Really NOT looking for "yeah, I don't have that problem" or "just don't use your pedals" answers. Would appreciate an informative suggestion.


Well, you won't get that from me. There is a serious problem with grounding and ground loops and people have died from similar situations. Only thing I can tell you is they need to get someone in who knows what they are doing to track the problem down. I would do it before someone gets hurt!

-Hal

[Gus Housen]

You need to have your outlets checked. Have you tried another DI w/o the pedal board?

Another possibility could be static electricity.

[John Roberts {JR}]

It's serious, tell the church to fix it..

In the meanwhile bring a long extension cord and plug you amp into same outlet as the IEM feed is coming from.

JR

[Art Welter]

Mark,

Did you lift the AC ground on the Bassbone or the shield (pin 1)?

Have you checked to see if the bass channel phantom power is turned off ?

Checked the mic cords are wired properly and pin one not connected to the case?

If the problem is not static electricity, or miswired AC outlets you should be able to determine where the problem lies with a V.O.M., checking between various interconnects.
Between the bass guitar ground and the Livewires quick disconnect would be the place to start.

Art Welter

[Eric Madson]

If it is unique to just that building it definitely sounds like an AC grounding issue. You have a voltage that is on AC ground and showing up in audio ground.

Do not lift AC grounds on your equipment because then you are the only path to ground. You can buy a cheap outlet tester that will show you if each outlet is wired appropriately (phase reversals, No ground). You can pick these up at any hardware store. They may still tell you the AC is wiring correct but that does not mean there is not a voltage potential at AC ground. You would have to measure with a VOM to determine this. Bring your concerns to the building owner. It is their responsibility and liability to assure that AC is up to snuff.

[Andrew Welker]

Mark  Allen wrote on Thu, 29 October 2009 15:12

The iem system is an Aviom.  I run my bass through a pedalboard anchored by a Radial Bassbone.  We've tried plugging the pedalboard into different outlets around the stage. I've lifted the ground on the Bassbone.  Nothing's prevented the problem.  The effect isn't enough to prevent me from playing, but at times it's barely tolerable. My guess is that there is some 'dirty' power on stage.  But, I don't understand why it would manifest itself this way.  No one else on stage (guitar amp, keys, etc) have any issues and, again, I don't have this problem in any other venue. Really NOT looking for "yeah, I don't have that problem" or "just don't use your pedals" answers.   Would appreciate an informative suggestion. Thanks!

Have you tried using a different Aviom mixer? Is the Aviom mixer powered via a local power supply or from the cat5 cable? Have you tried switching how the Aviom mixer is powered?

[Tim A Perry]

By chance is the location within a mile of the KOA transmitter?

http://maps.google.com/maps?f=q&hl=en&q=39.50611,+-1 04.76583+(KOA-AM)&om=1

Or within a kM of a lower powered AM station?


http://www.radio-locator.com/cgi-bin/locate?select=city& city=denver&sid=

[Mac Kerr]

Tim A Perry wrote on Thu, 31 December 2009 12:24

By chance is the location within a mile of the KOA transmitter?

Almost every response in this thread asked the OP a question. He has not responded to any of them. He has not logged in since Nov. 4. I wouldn't expect much.

Mac

[Mark Allen]

Mac - Thanks for the 'wake up call' on this.  VERY sorry I haven't responded to this sooner;  "I'm busy / haven't played at this church in a couple of months / I forgot about my posting / etc. ,,," all the usual (but no less irrelevant) excuses.    In reality though, my schedule (especially around Christmas) keeps me pretty busy and I haven't played this venue since my posting.  Now that it's a new year I'm starting to again and I'm playing it this weekend.  Played last night - and, sure enough, the little electrical dance starts again.  

I HAVE tried lifting the ground at the main interface on my pedalboard (a Radial Bassbone), we've plugged my rig into every other outlet on stage, switched out the Aviom station,,,, no change.  Interestingly enough, I've also started noticing the problem at one of my other churches.  BOTH of these venues have lousy power on-stage;  evidenced by constant buzzing and noise coming out of the bass rig.  (I'm not sure why the guitar amps don't buzz too.)  However, the shock I receive at the other church is minor in comparison to the church I'm posting this about.

A parishioner at this church (an electrician) recently has been going over the wiring.  This church building is relatively new - less than 5 yrs old.  He HAS noted that the company that installed the wiring apparently took several 'short cuts' that, while still within code undoubtedly contributes to this problem.   He didn't specify the short cuts.  I could ask him to elaborate if it would help.  But he also postulates that the reason I'm receiving shocks is that there is something about my pedalboard - either the wiring or the gear - that makes it a more 'attractive' path to ground.  

Since I've discovered I'm receiving these shocks at more than one venue I need to take a 2nd look at my pedalboard.  It's pretty simple:  a Radial Bassbone that feeds a Peterson Strobostomp tuner at it's tuner output jack.  In it's effects loop (using a custom made Lava Cable insert cable) I have a Carl Martin Compressor and a Eventide PitchFactor.  I've also started using a new Tech 21 VT pedal outboard.  The Bassbone and PitchFactor both use their own wall wart power supplies.  The Carl Martin has a built-in power supply so it just plugs into my ac strip - a Furman SS-6B, and the Peterson is being fed by a 1 Spot 9v adapter.  I'm not sure what I can do to make this little rig less susceptible to this issue - but I'm open to suggestions.

Lastly, here's an interesting article posted by the manufacturer of my in-ears >> http://www.fidelitycustomearphones.net/shocking-isnt-it/ .  Obviously I'm not the only one experiencing this issue. I DON'T think this problem is going away.