DJing Discussion

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Clean Power for Mobile Dj

LMiller 2:52 PM - 11 September, 2017
Just wondering what you guys use for power conditioning/regulating?(more than just a surge protector) I had a venue with pretty bad power on Sat which gave me a lot of buzz. I tried the old ground lift adaptor to confirm, but I don't feel safe running ungrounded with 100's of people/children running around.

Seems like there are the $1k+ options like furman p-1800 or cheaper regulators like the Tripp Lite LC2400...

Thanks
deezlee 5:38 PM - 11 September, 2017
i say lift the ground. I've run my stuff ground lifted a whole lot like usually. Most of my power strips have the third prong busted off at this point. Catch a buzz, lift the ground, done. Unless yer djing on a boat I wouldn't trip. I've never heard of an injury from an ungrounded price of equipment in my 25 yrs of doing sound.
DJ Reflex 2:31 AM - 13 September, 2017
The ground is there in case your equipment is damaged. If your speakers, mixer, cords, etc are in good working order (and anything that is plastic), you won't need the ground. There should be no current running through that green wire anyway! Only around wet conditions - like deezlee said... on a boat - you'll be fine.

Most "Power Conditioners" are garbage anyway. I use a Furman, but only as an extra source of outlets. I made the mistake of opening it up once and realized it basically has no guts to it... just a 15 amp trip switch and a choke coil soldered to the first outlet. Hardly any electronics - just empty space! I felt kinda duped, but also know that my equipment works fine with straight wall power.

Hint: Bring a small electrical tester with you to check proper wiring at venues. I've run into some shady places before and have it in my contract that "clean and proper" power is a requirement. Full 15 amp circuit wired correctly.

www.amazon.com
deezlee 5:49 AM - 13 September, 2017
Pro tip:
Bust the third prong off of a power strip to ground lift a bunch of equipment at once. :)
LMiller 1:46 PM - 13 September, 2017
yeah, done that, just don't like running stuff ungrounded, I'm looking for other alternatives...
DJ Reflex 11:05 PM - 13 September, 2017
I spent most of my childhood grounded!
Rebelguy 12:03 AM - 14 September, 2017
A little excerpt from a prosoundweb article on why the ground is needed.

"Electricity always wants to get back to ground, or earth, and will always take the path of least resistance. Should there be a short inside an appliance, the chassis of said appliance could become energized. If you touched it and happened to be providing a good path to ground, that current will flow through you. Since it only takes about 20 milliamps to stop your heart, it’s very possible that a short like that could kill you. This is why we never solve ground loops with “cheater plugs” that effectively lift the safety ground."
deezlee 5:19 AM - 14 September, 2017
That's true.
I do play at dives where half the time their sound is ground lifted anyway. Or worse.
westom 9:54 PM - 15 September, 2017
Quote:
yeah, done that, just don't like running stuff ungrounded, I'm looking for other alternatives...

Electronics works fine with or without that safety ground. Safety ground only exists to protect human life. If floating (lifting) a ground improves sound, then the system has an internal defect. Safety ground must remain connected.

That is completely different from something that has no relationship to safety ground. Some numbers. A 120 volt protector would have a 330 let-through voltage. That means a protector does absolutely nothing until 120 volts well exceeds 330 volts. Protector does nothing (remains inert) for tens or less volts of noise. That protector also does nothing for human safety other than make that required connection to a wall receptacle safety ground.

Finding noise requires a two step process. First an entire current loop must be identified. For example, disconnect a wire between B and C might eliminate noise. But a defect is in A - a current loop that goes from A to B to C to A. So that loop must be identified long before identifying a defective part causing noise.

Lifting a ground is simply disconnecting B to C; only cures a symptom; does not identify and eliminate a defect.

Surge protector also does nothing to solve a noise problem.
DJ Reflex 11:43 PM - 15 September, 2017
Try this... Some XLR audio connectors (and 1/4 inch TRS) are wired with the ground attached to the chassis at pin 1. Open your connectors and see if the bare wire is split and soldered to pin 1 AND the metal frame of the connector. If so, cut or remove the connection to the metal connector, allowing pin 1 to only connect to the bare wire.

Your ground issue might be an audio connection, not a 120v electrical one. Some equipment grounds the audio, some does not. DI boxes use a "ground lift" in the audio connection to eliminate buzz.
deezlee 6:18 AM - 16 September, 2017
The ground lifting isn't to deal with a defect in the equipment, it's to deal with a crappy electrical system at the venue.
westom 12:49 PM - 16 September, 2017
Quote:
The ground lifting ... it's to deal with a crappy electrical system at the venue.

What defect? Ground only is protection of human life. It does nothhing to make equipment work better (or worse). Define this thing called 'crappy'.
Hanginon 3:01 PM - 16 September, 2017
Quote:
What defect? Ground only is protection of human life. It does nothhing to make equipment work better (or worse). Define this thing called 'crappy'.


+1 However, the one place I will use a cheater plug to ground lift is on a laptops power supply if it has a ground prong. Defiantly helps with a current loop going through the USB cable to your controller.
deezlee 3:38 PM - 16 September, 2017
I thought you were saying that lifting the ground was used to compensate for faulty equipment. I was pointing out that it's to compensate for venues with faulty power. I can't rewire their electricity but I can get rid of the damn sound.

If you ground lift your laptop you will die!!!!!!!!! :)

Anyone have a link to an article about a DJ dying from a lifted ground in a club?
deezlee 3:41 PM - 16 September, 2017
I tried to find one but all I found was a DJ dying in a car crash in the way to the venue.
TAKE THE BUS OR DIE!!!!!!
westom 7:30 PM - 16 September, 2017
Quote:
However, the one place I will use a cheater plug to ground lift is on a laptops power supply if it has a ground prong.

So you 'lift a ground' to mask what is defective hardware. Floating ground (a human safety threat) is created rather than fix or remove defective hardware.

Why is a longitudinal mode current flowing through a differential mode interface? That implies a defect exists. Fix the defect. Never cure symptoms by intentionally creating a threat to human life.

The informed start by identifying that current loop - A to B to C to A. A USB might be between A and B. A ground disconnected between B and C is 'lifted' to mask a defect in A. Too many want to cure symptoms (by even creating a human safety threat) rather than fix a defect.
LMiller 8:11 PM - 16 September, 2017
I don't think death is something I'm worried about, but I have been shocked in the mouth more than I would like when going to sing/talk at various venues with bad grounding, add to that all the spilled drinks that are involved in our profession, it is just a variable I would like to take out of our busy equation, not fearing for my life. Just want to be as professional as possible so I can charge enough to make a living...
Hanginon 8:23 PM - 16 September, 2017
Quote:
Quote:
However, the one place I will use a cheater plug to ground lift is on a laptops power supply if it has a ground prong.

So you 'lift a ground' to mask what is defective hardware. Floating ground (a human safety threat) is created rather than fix or remove defective hardware.

Why is a longitudinal mode current flowing through a differential mode interface? That implies a defect exists. Fix the defect. Never cure symptoms by intentionally creating a threat to human life.

The informed start by identifying that current loop - A to B to C to A. A USB might be between A and B. A ground disconnected between B and C is 'lifted' to mask a defect in A. Too many want to cure symptoms (by even creating a human safety threat) rather than fix a defect.


Absolute nonsense. The output of the typical PC laptop power supply is 19VDC. Many are double insulated and have a two prong AC connector. However, even on those with a three prong connector, you'd have to stick it in your mouth and go swimming in salt water to have any risk of life or limb.

Ground loops, however, are a real problem, and occur all the time, even in perfectly functional hardware.
westom 9:17 PM - 16 September, 2017
What hardware is two wire or three is completely irrelevant to the defect. That ground loop exists due to some hardware defect. Lifting the ground only cures a symptom. And creates a human safety threat. Every three wire electronics must connect to that safety ground. if that causes noise, then a hardware defect exists - elsewhere.

Never solve a defect by creating a human safety threat - ie lifting (floating) a safety ground. You post completely ignores that reality - and a defect that creates ground loop noise.
Hanginon 9:30 PM - 16 September, 2017
Quote:
That ground loop exists due to some hardware defect.

More nonsense. Any time a piece of hardware has more than one path to ground, the potential for a ground loop exists - even in perfectly functional equioment.
deezlee 5:58 AM - 17 September, 2017
^^^
Yup

Like I said it's the wall I'm compensating for not the equipment.

Anyway, I would of course say to properly ground your equipment and not lift the ground unless you have no other option.

Getting zapped by a mic is undeniably wack

But im not gonna ruin someone's event because I'm scared to use a ground lifter for a speaker.
DJ Reflex 11:02 PM - 17 September, 2017
If you have any Chinese gear whatsoever... open it up and look for the ground connection...

There isn't any!

All this fuss over "human life safety" is bull when most of your gear isn't properly grounded anyway. Hanginon is correct - the ground issue stems from any difference in voltage between two separate ground paths. It has nothing to due with faulty equipment.
westom 1:19 PM - 19 September, 2017
Some electtronics do not have a safety ground (third prong). Therefore ground loop current are routine? Of course not. Only bull is a poster who forgets to learn how hardware works.

Properly designed equipment use features such as galvanic isolation so that ground loop currents do not exist. Otherwise every two prong, electronic appliance would create massive ground loop currents and noise. Potential differences and ground loop currents are averted when those features have not failed.

Faulty equipment means a feature that averts ground loop currents has failed. The naive want to 'cure' it by disconnecting wires - ie lifting a safety ground. If that plug has a third prong, then it must have a safety ground connection to protect human life. That safety ground must not be compromised (lifted - disconnected). That ground exists only to to protect human life (ie avert a shock from the microphone).

First locate and then fix a hardware defect. Never cure symptoms as other may do by 'lifting the ground'.
deezlee 4:03 PM - 19 September, 2017
Have you ever gotten to a venue for a wedding or something w quick setup and caught a ground buzz at the last second setting up? And you forgot your isolation boxes or whatever.

"Sorry I won't provide sound, it's too dangerous to lift the ground"

Or maybe you have been 100% prepared and never run into the problem.
I guess I've done a lot of gigs with combined/borrowed/rented/neglected sound systems.

Heck, I've saved other people's gigs by fixing the ground buzz issue by risking their lives w a ground lift. :)

To reiterate: Fix it another way if possible, but in a pinch lift the ground, it'll be o.k.
Hanginon 4:57 PM - 19 September, 2017
Quote:
First locate and then fix a hardware defect. Never cure symptoms as other may do by 'lifting the ground'.

The biggest problem most of us will have with ground loops is the laptop. Here's a video of a perfectly functioning laptop that causes a ground loop.

Watchwww.youtube.com

If you decide to not use a cheater and actually get a double insulted laptop power supply, the symbol he is referring to is a square within a square.

I'm tired of discussing this - westom, the floor is all yours.
westom 7:14 PM - 19 September, 2017
It never fails to amaze me how some are so attached to myths as to completely ignore facts. Posted previously was the ground loop.
Quote:
For example, disconnect a wire between B and C might eliminate noise. But a defect is in A - a current loop that goes from A to B to C to A. So that loop must be identified long before identifying a defective part causing noise.

Lifting a ground is simply disconnecting B to C; only cures a symptom; does not identify and eliminate a defect.

A is a USB device. B is a laptop. C is a speaker/ amp. Disconnect a B to C connection interrupts that ground loop. But the defect remains in A. A is apparently the source of a defect - a voltage potential that creates a ground loop current.

Too many get entrenched in assumptions, wild speculation, hearsay, and myths. Therefore cannot learn from their mistakes - or that video.