http://www.engineeringharmonics.com/

The president of this company (phil Giddings) is one of the world's top experts in the area of grounding.

here is a website from the same company. It offers some white papers on the subject.

[Link: engineeringharmonics.com]

LOL,, really. must be nice to have exactly 110Volts, what's you secret

It must be the metric system. You know how 2.2 pounds = 1 kilogram? Apparently 2.2 Hz = 1 volt, so 2.2 x 50 = 110.

the CEDIA course was far too short (as many of them are) to be effective. I don't believe Bill Whitlock is still teaching that course for this very reason.
NSCA is the place to take it.



Your loop is probably on the video cables. You have removed the safety ground from the device. It is possible that the unit could short internally, putting 120Volts on the chassis without tripping the breaker. The ground is not there for the performance of the equipment but the safety of the user. In your case you are taking a calculated risk. For an installer to leave it that way in a customers home is a different story.

depends on the signal and the wire. I haven't had 60 hz hum induced onto the wire in a long time. fingers crossed. I use Belden 1266 mic line for all of my line level runs. It comes in every color in the rainbow. I use what's commonly called the "telescope" wiring. red to center, black to ground & shield tied to ground at the send end. your shield is NOT part of the signal path this way. I don't do a lot of pro work but I have never had to just leave pin one lifted. the shield should be routed outside of the xlr and tied directly to the chassis. lifting pin one doesn't work if you need phantom power.

I agree with what you have said. I should have been more specific. When I lift pin one on an XLR connector, it's in a situation where I'm going from balanced +4 to unblance -10. In some situations. this solves a problem. a properly balanced system ussually deals with induction, even in LZ signals. However, a mic. line can still allow a 60Hz induction if it is strong enough, or close enough for a long enough distance. This is why in any venue, the audio spec. is very clear on proximity of signal carrying conducters to AC voltage lines. PVC tubing will of course not stop this problem, neither will copper or aluminum conduit. Steel conduit is the only pipe that will be effective . If the noise is being generated by the electrical system, a high quality ac transformer might be required. They are expensive, but clean up the power. And no, they don't afect the audio quality, in fact, if anything, it will be improved by virtue of the absence of the hum.

Hmm... maybe. I have a rather complicated set of video connections from the DVD, involving component, S-Video *and* composite. Still, having multiple grounds in a system is a good way to promote loops.

Larry, I used to think I had a weight problem until I became friendly with the metric system.

Hmm, as I type this, do I recall that the metric system has gotten you back into shape as well?

I'm in shape. Round is a shape, isn't it??

50hz has its unique set of problems.We use NTSC here so any kind of ground loop, leakage etc. causes a heavy 10 hz (60-50) flicker. 10 hz flickers have been known to trigger epilepsy attacks.

Also, CCTV monitors end up with 10hz flicker if lighting in the monitored area is flourescent.

"D-oh!"

"Nuts!"

"Mmmmmmmm, donuts!"

I used to think gas was expensive until I saw it for 56 cents per liter. Imagine that! Only $.56

I remember back (way back) when I was a kid (well, physically). It was a Sunday afternoon, and the family was headed to the community pool.

As we rounded the corner, my dad looked at the sign at the gas station, and said, "I can't believe it! Gas has hit 30 cents a gallon!"

Now I see it's "dropped" below $1.70/gal and think what a great price it is. Sheesh!