ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  
Pages: [1] 2  All   Go Down

Author Topic: 70 Volt system com vs 70v  (Read 3568 times)

Bradford "BJ" James

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 354
70 Volt system com vs 70v
« on: November 06, 2008, 12:14:25 pm »

Hi,
I'm going over to a local service club to replace their fried 70v mixer/amp. Just curious: since I don't actually have access to the speakers(in the suspended ceiling)is there a way to check to make sure what wire is the common and which is the 70v? All I have access to is the 2 wires coming out of the wall, and they're not labelled. Can I f*** anything up having the wires crossed?
Logged

Joseph Macry

  • Full Member
  • ***
  • Offline Offline
  • Posts: 144
Re: 70 Volt system com vs 70v
« Reply #1 on: November 06, 2008, 04:28:04 pm »

Shouldn't matter.  If you get them backwards, you've simply reversed polarity and no one will notice.  As long as everything is equally out of polarity....
Logged
Joseph Macry
Austin TX

Phil LaDue

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4039
Re: 70 Volt system com vs 70v
« Reply #2 on: November 06, 2008, 04:35:45 pm »

By suspended ceiling do you mean grid and tile?

Bradford "BJ" James

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 354
Re: 70 Volt system com vs 70v
« Reply #3 on: November 06, 2008, 05:35:42 pm »

re ceiling:Yes.
And ya once I got thinking about it, it would only reverse polarity....no biggie.
Thanks,
BJ
Logged

Brad Weber

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2477
Re: 70 Volt system com vs 70v
« Reply #4 on: November 06, 2008, 06:06:10 pm »

Perhaps a little obvious, but couldn't you simply look at what is connected to what on the existing amp or look at the system documentation?
Logged
Brad Weber
muse Audio Video

Hal Bissinger/COMSYSTEC

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 487
    • http://www.comsystecusa.com
Re: 70 Volt system com vs 70v
« Reply #5 on: November 06, 2008, 07:08:36 pm »

When I install a system I normally prefer to use wire that has black and red conductors, however I have used black and white if necessary. Either case black is always the common, (-) or ground. This allows you to get the speakers wired the same and in phase. It doesn't matter which way you connect it to the amp  output (assuming only one amp) but good practice is to follow the same convention.

Of course the typical hack job uses lamp cord or something just as bad so if that's the case all bets are off.

-Hal

Bradford "BJ" James

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 354
Re: 70 Volt system com vs 70v
« Reply #6 on: November 06, 2008, 07:10:32 pm »

Amp is fried, I'm not sure it was connected properly to start with. It's just a crappy little radio shack amp though- failure was imminent.
Logged

Hal Bissinger/COMSYSTEC

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 487
    • http://www.comsystecusa.com
Re: 70 Volt system com vs 70v
« Reply #7 on: November 07, 2008, 11:08:06 am »

You just might want to check to see that there are line transformers on each speaker and they are connected properly before you replace that amp. But then again that's just me...

-Hal

Don Boone

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 782
Re: 70 Volt system com vs 70v
« Reply #8 on: November 07, 2008, 03:00:32 pm »

It's TOA Z-104 time.

Don
Logged

Rain Jaudon

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 626
Re: 70 Volt system com vs 70v
« Reply #9 on: November 07, 2008, 03:20:42 pm »

http://www.markertek.com/Product.asp?cat=TESTTOOLS&subca t=&prodclass=AUDIOTEST&baseitem=ZM-104&search=0& amp;off=0&showreturn=0&utm_source=gbase&utm_medi um=shoppingengine&utm_term=&utm_content=&utm_cam paign=sf

TOA ZM-104
Logged
Endorsing Artist for CA Guitars - Lafayette, LA
http://www.CAguitars.com

Multitude Audio
Subcontracting under Magnolia Music Center
Audio Visual Installation and Service
Gulfport, Ocean Springs and Pascagula, MS
Pages: [1] 2  All   Go Up
 

Page created in 0.057 seconds with 20 queries.