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Joined: Nov 2004
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Sorry if this has been asked, I searched the forum and didn't see it.
We're installing new additional paging speakers in a factory, in a newly added area. They wanted the new section on its own amplifier with 20 70v speakers, everything works, but pages are quiet and 'tinny'. We're about 1000' from the signal source. I have a bet with one of our guys that it's because of the distance between source and amp, he thinks its a problem with the amp, even though if I put a tone directly into the input, it's loud as hell.
Help me win a beer...
"It's like the man said...never take life too seriously, you'll never get out of it alive" Bugs Bunny
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Moderator-1A2, Cabling
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What sort of equipment are you using? You may need a Line Level input for a distance of 1,000'.
Sam
"Where are we going and why are we in this hand basket?"
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Joined: Feb 2006
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Is the source a paging output from a telephone system?
Most 600 ohm paging systems have a maximum output of 0 db .7VAC. At a thousand feet, this means that on a 22 gauge wire, you will have introduced approximately 16 ohms of resistance and 32 ohms for the loop. Considering insertion loss and amplifier input unity, you may have less than a quarter of the voltage needed to drive the input of the amplifier.
You may try and pre-amp the paging to the amplifier and get the levels up to, at least, 0 db.
Rcaman
Americom, Inc.
Where The Art And Science Of Communications Meet
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Joined: Nov 2004
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Coming out of a Panasonic KXTDA100 paging port. I have an unused Viking pa-2a amplifier I was going to try and send a very lightly amplified signal, but was worried about blowing the far amp.
"It's like the man said...never take life too seriously, you'll never get out of it alive" Bugs Bunny
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Just as I thought. You need a line level 600 ohm to 600 ohm amplifier. You don't need anything expensive. If you are handy with a soldering iron, you can make one for about $20.
If you want to use the Viking unit, you will need an 8 ohm to 600 ohm matching transformer.
Rcaman
Americom, Inc.
Where The Art And Science Of Communications Meet
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Coming out of a Panasonic KXTDA100 paging port. I have an unused Viking pa-2a amplifier I was going to try and send a very lightly amplified signal, but was worried about blowing the far amp. As was said previously the distance from the source to the amp is too far. I would suggest moving the amp next to the source and run 14/2 or 16/2 (at the min) cable to the speakers. THe cost should be less that buying a 600 ohm to 600 ohm amp. The Viking PA-2A Amplifier has a 600 ohm audio out, but the data sheet doesn't say at what level. Also never connect the amplifier output to the source input of another amp as it will fry the input no matter how low of a signal you use. What is the main amp for the new system? Many have an input sensitivity adjustment that you might be able to adjust. Also what gauge of wire did you use for 1000 ft the source run? I personal would recommend moving the amp next to the source and running a new cable with a larger gauge wires.
Patrick T. Caezza
Santa Paula, CA 93060
C-7 - Low Voltage System Contractor - Lic# 992448
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The Viking unit should work fine but you still need a isolation transformer so do as Rcaman suggested and find a transformer to match the Viking and amplifier input.
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Joined: Feb 2006
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You can get matching transformers for as little as $4. Click Here You can drive ANY amplifier with another amplifier. It's called bridging. But, in your case, you need to just bump up the input level to drive the amp. Rcaman
Americom, Inc.
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Sorry, I made a mistake. Feeding the output of one amplifier into another is called cascading and has been done for years. All that is required is a proper matching transformer and, at times, an attenuator, if needed.
Bridging is the common method of sending the same signal to the input of two different amplifiers. Some amplifiers have bridging connections to do that.
Some of the older Vacuum tube amplifiers had high level low Z inputs to accommodate cascading. Today, you have to do the matching yourself.
Rcaman
Americom, Inc.
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I bet RDL would have something to do this.
Jeff Moss
Moss Communications
Computer Repair-Networking-Cabling
MBSWWYPBX, JGAE
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