ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 [2]  All   Go Down

Author Topic: Digital console power.  (Read 1435 times)

Chris Hindle

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 1654
  • Montreal, Quebec, Canada, Earth, Sol System,......
Re: Digital console power.
« Reply #10 on: June 27, 2019, 12:53:14 pm »


I started doing this 35 years ago back in the days of analog desks and massive "Pin 1 problems" and have found no reason to change it.

Say I take power for FOH that's "local".  I have no idea what else is on the circuit or who has access to any other outlets.  I don't know who has access to the circuit breaker or even where it's located.  Those are things that give me heartburn because IF something goes wrong we're not able to immediately fix it.
Ha!
Back in the "real console" days, if you were to go local at FOH, and somebody plugged in a lightbulb on the same circuit, you'd know it pretty quick.
Today's loads are a lot "easier", but out of habit, a distro goes out, and EVERYTHING is supplied by the distro. Stage, backline, squints, and FOH.
Chris.
Logged
Ya, Whatever. Just throw a '57 on it, and get off my stage.

Tim McCulloch

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 20506
  • Wichita, Kansas USA
Re: Digital console power.
« Reply #11 on: June 27, 2019, 01:43:43 pm »

Ha!
Back in the "real console" days, if you were to go local at FOH, and somebody plugged in a lightbulb on the same circuit, you'd know it pretty quick.
Today's loads are a lot "easier", but out of habit, a distro goes out, and EVERYTHING is supplied by the distro. Stage, backline, squints, and FOH.
Chris.

Yep, and to expand on that...

If there is a failure we know *exactly* where to look - we know which distro, which breaker(s), and how the cable path runs.  If the issue presents during setup we can troubleshoot in a few seconds, not waiting on the building engineer or facility maintenance person to show up with keys...

Being *fully* self contained means we're only at the mercy of our own workmanship and product selections.
Logged
"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Rob Spence

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3348
  • Boston Metro North/West
    • Lynx Audio Services
Re: Digital console power.
« Reply #12 on: June 27, 2019, 02:02:27 pm »

While the Cat-5 is transformer isolated balanced pairs, the shield is not!

If there is a significant difference in ground potentials across the cable, current will flow on the shield. Might be significant current.

While the remote stage box is unlikely to produce ground loop induced hum, it still may be susceptible to static discharge noise (see many pages of threads on X32 issues).
Logged
rob at lynxaudioservices dot com

Dealer for: AKG, Allen & Heath, Ashley, Astatic, Audix, Blue Microphones, CAD, Chauvet, Community, Countryman, Crown, DBX, Electro-Voice, FBT, Furman, Heil, Horizon, Intellistage, JBL, Lab Gruppen, Mid Atlantic, On Stage Stands, Pelican, Peterson Tuners, Presonus, ProCo, QSC, Radial, RCF, Sennheiser, Shure, SKB, Soundcraft, TC Electronics, Telex, Whirlwind and others

Frank Koenig

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 872
Re: Digital console power.
« Reply #13 on: June 27, 2019, 05:33:21 pm »

While the Cat-5 is transformer isolated balanced pairs, the shield is not!

Good point! I suppose the shield could be broken (at one end) with a capacitor, or maybe a TVS type of device, that is sized to help with ESD while keeping power-line ground currents sufficiently small. Better to use UTP if you can so that you're truly isolated up to the breakdown voltage of the transformers.

I have taken advantage of a UTP-only connection to FOH on a few occasions, but all were indoors in modern buildings with good electricals. -F
Logged
"Nature abhors a vacuum tube." -- John Pierce, Bell Labs

Roland Clarke

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 815
Re: Digital console power.
« Reply #14 on: July 07, 2019, 05:27:44 pm »

Good point! I suppose the shield could be broken (at one end) with a capacitor, or maybe a TVS type of device, that is sized to help with ESD while keeping power-line ground currents sufficiently small. Better to use UTP if you can so that you're truly isolated up to the breakdown voltage of the transformers.

I have taken advantage of a UTP-only connection to FOH on a few occasions, but all were indoors in modern buildings with good electricals. -F

You see, when I posted this it did occur to me that it wasnít necessarily a cut and dried case! 😁  Iíve always done as Tim says running power from my own distro system, star earthing everything, but Iíve got enough time in the business to know this was best practice and even recently there have been a couple of threads on here with very obvious differences in ground potential problems.  Of course with digital there are many reasons why in certain circumstances you could get away with this, glass being one and potentially any situation where it is only a digital signal and no analogue.  What about lifting the shield on one end of the cat 5, would that reduce your transmission distance?  How about lifting the earth on the desk?  With the low power in use with a digital desk, does that present any significant risk, particularly if you have the shield on the cat 5 offering a ground? 
Logged

Jonathan Johnson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3004
  • Southwest Washington (state, not DC)
Re: Digital console power.
« Reply #15 on: July 18, 2019, 05:57:20 pm »

Being *fully* self contained means we're only at the mercy of our own workmanship and product selections.

I've learned that anything I don't provide is something I can't fully trust.

Shoot, I don't even fully trust my own stuff, but at least I know its idiosyncrasies and if something goes wrong, I don't have to look to someone else for the fix.
Logged
Stop confusing the issue with facts and logic!

ProSoundWeb Community

Re: Digital console power.
¬ę Reply #15 on: July 18, 2019, 05:57:20 pm ¬Ľ


Pages: 1 [2]  All   Go Up
 



Page created in 0.071 seconds with 24 queries.