ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: 25 / 70 volt amplifier help  (Read 1663 times)

Mitchell Pittman

  • Newbie
  • *
  • Offline Offline
  • Posts: 1
25 / 70 volt amplifier help
« on: February 29, 2016, 09:16:17 pm »

We recently put in some new ceiling mics and added 2 new 8-inch ceiling speakers to a church that was expanding their building. They don't have anyone there that really knows anything about their audio system and on the day I went down there to hook their amp and soundboard back up, their amp was missing, probably stolen.

I have been trying to find them a replacement amp and want to make sure I get something that will work properly. Part of the problem is the transformers for the existing speakers aren't at the speakers they are at the edge of the church where the roof meets the ceiling. I can see them from a distance in the attic but can't get close enough to get any information off of them, so I'm not 100% sure if they are a 25 Volt or 70 volt system and since they don't have the original amp I can't check and see what it was set to.

The speakers have been wired with the ones on the left and right separately with 4 speakers on each side, including the 2 new ones. The two new ones can be tapped up to 5 watts, the old ones I have no idea.

I'm trying to keep the cost down to around $300. So far I'm looking at getting two of these if I can make sure it is a 70 volt system (The input coming into the amp has an RCA connector):

http://www.bhphotovideo.com/c/product/1100870-REG/atlas_sound_pa40g_pa60g_40w_single_channel_power.html

or two of these if it is a 25 volt system:

http://www.staples.com/Pyle-PCM60A-100-W-Power-Amplifier-With-25-and-70-Volt-Output/product_283646

Also, would it hurt anything if I set the amp to 25 volts to test it and see how it works, then change it to 70 volt if need be?

Any advice or suggestions would be greatly appreciated.

edited for clarity
« Last Edit: March 01, 2016, 05:55:47 am by Mitchell Pittman »
Logged

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 8642
  • Atlanta GA
Re: 25 / 70 volt amplifier help
« Reply #1 on: March 01, 2016, 07:36:27 am »

We recently put in some new ceiling mics and added 2 new 8-inch ceiling speakers to a church that was expanding their building. They don't have anyone there that really knows anything about their audio system and on the day I went down there to hook their amp and soundboard back up, their amp was missing, probably stolen.

I have been trying to find them a replacement amp and want to make sure I get something that will work properly. Part of the problem is the transformers for the existing speakers aren't at the speakers they are at the edge of the church where the roof meets the ceiling. I can see them from a distance in the attic but can't get close enough to get any information off of them, so I'm not 100% sure if they are a 25 Volt or 70 volt system and since they don't have the original amp I can't check and see what it was set to.

The speakers have been wired with the ones on the left and right separately with 4 speakers on each side, including the 2 new ones. The two new ones can be tapped up to 5 watts, the old ones I have no idea.

I'm trying to keep the cost down to around $300. So far I'm looking at getting two of these if I can make sure it is a 70 volt system (The input coming into the amp has an RCA connector):

http://www.bhphotovideo.com/c/product/1100870-REG/atlas_sound_pa40g_pa60g_40w_single_channel_power.html

or two of these if it is a 25 volt system:

http://www.staples.com/Pyle-PCM60A-100-W-Power-Amplifier-With-25-and-70-Volt-Output/product_283646

Also, would it hurt anything if I set the amp to 25 volts to test it and see how it works, then change it to 70 volt if need be?

Any advice or suggestions would be greatly appreciated.

edited for clarity
I would first do an IMPEDANCE sweep (NOT DC resistance) and that will give you an idea of where they are tapped.

The difference between 25 and 70V is 9dB.  Which is pretty substantial.

It would be a little bit of guess work on your end to figure out what sort of levels you are getting vs the input voltage and speaker type.

But at least with an impedance sweep you would know what your actual load on the amp would be-no matter how you hooked it up.
Logged
A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Frank DeWitt

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 973
    • LBP DI Box
Re: 25 / 70 volt amplifier help
« Reply #2 on: March 01, 2016, 08:35:09 am »

To save money on the new amp, I would go with a used TOA on Ebay.  They are good solid amps and go crazy cheep used.
Logged
Not to Code

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 8642
  • Atlanta GA
Re: 25 / 70 volt amplifier help
« Reply #3 on: March 01, 2016, 11:39:53 am »

To save money on the new amp, I would go with a used TOA on Ebay.  They are good solid amps and go crazy cheep used.
Those old TOA 70V amps are pretty reliable and just keep on working.
Logged
A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Jerome Malsack

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1273
Re: 25 / 70 volt amplifier help
« Reply #4 on: March 02, 2016, 08:15:31 am »

Toa   A-912 mk 2  is 8 input    120 watt
        P-912         is 1 input     120 watt
        P-924         is 1 input     240 watt
        M-900        is  8 input   mixer only

So if the speakers a connected at 20 watts per, X 8 speakers,
you need over 160 watts roughly.   P-924 would be best.

or if you can do left side 4 on a p-912 and right side on a p-912 it may work well for you. 

they also have  906 and 903   60 watt and 30 watt.   
« Last Edit: March 02, 2016, 08:21:10 am by Jerome Malsack »
Logged
Pages: [1]   Go Up
 


Page created in 0.038 seconds with 21 queries.