Using Elk-800 Amps for Phone Paging

[upstatemike]

I am thinking of using Elk-800 amps to provide additional phone paging speakers in areas that do not have speakerphones. I like the idea of using low voltage utp instead of 70V distribution but I'm not sure how to drive the line. The page output on the Panasonic phone sytem is high impedance line level and I'm thinking that it will have problems driving a long run of utp. Would the correct application be to install an Elk-800 at the phone system and then use the speaker line out from that to drive the utp that daisy-chains to the other remote Elk-800 inputs?

 

[upstatemike]

I see that the input impedance on the Elk-800 is 1000 ohms which is kind of low for connection to a line level output. Do I need a transformer or resistor pad to couple this correctly to the line out on my Panasonic phone system? Is anybody using these amplifiers with a source that has a line level output rather than a low impedance speaker or microphon output?

 

[fcwilt]

I am thinking of using Elk-800 amps to provide additional phone paging speakers in areas that do not have speakerphones. I like the idea of using low voltage utp instead of 70V distribution but I'm not sure how to drive the line. The page output on the Panasonic phone sytem is high impedance line level and I'm thinking that it will have problems driving a long run of utp. Would the correct application be to install an Elk-800 at the phone system and then use the speaker line out from that to drive the utp that daisy-chains to the other remote Elk-800 inputs?

What is the impedance of the paging output? I have not been able to find the specs for it.

 

[upstatemike]

I am thinking of using Elk-800 amps to provide additional phone paging speakers in areas that do not have speakerphones. I like the idea of using low voltage utp instead of 70V distribution but I'm not sure how to drive the line. The page output on the Panasonic phone sytem is high impedance line level and I'm thinking that it will have problems driving a long run of utp. Would the correct application be to install an Elk-800 at the phone system and then use the speaker line out from that to drive the utp that daisy-chains to the other remote Elk-800 inputs?

What is the impedance of the paging output? I have not been able to find the specs for it.

Turns out it is 600 ohms (for some reason I thought it was higher) so going into the 1K input on one Elk-800 should be fine. I am still trying to figure out how to drive a long line of daisy-chained Elk-800s though... It still looks like I would need one amp at the source and then use the output from that to drive the line feeding the remote amplifiers. The output of an Elk-800 can go down to 2 ohms so I figured I would have one 8 ohm speaker local to the source and then a dozen remote amps. The combined impedance of the remote amps will be 125 ohms plus wire resistance. That in parallel with the local 8 ohm speaker will still be a 7.5 ohm load on the head end amplifier so no issues there.

Is there a better way to approach this?

 

[fcwilt]

I am thinking of using Elk-800 amps to provide additional phone paging speakers in areas that do not have speakerphones. I like the idea of using low voltage utp instead of 70V distribution but I'm not sure how to drive the line. The page output on the Panasonic phone sytem is high impedance line level and I'm thinking that it will have problems driving a long run of utp. Would the correct application be to install an Elk-800 at the phone system and then use the speaker line out from that to drive the utp that daisy-chains to the other remote Elk-800 inputs?

What is the impedance of the paging output? I have not been able to find the specs for it.

Turns out it is 600 ohms (for some reason I thought it was higher) so going into the 1K input on one Elk-800 should be fine. I am still trying to figure out how to drive a long line of daisy-chained Elk-800s though... It still looks like I would need one amp at the source and then use the output from that to drive the line feeding the remote amplifiers. The output of an Elk-800 can go down to 2 ohms so I figured I would have one 8 ohm speaker local to the source and then a dozen remote amps. The combined impedance of the remote amps will be 125 ohms plus wire resistance. That in parallel with the local 8 ohm speaker will still be a 7.5 ohm load on the head end amplifier so no issues there.

Is there a better way to approach this?

I would check to see if the input and the output share a common ground. If so I think you should be ok, except perhaps for the noise level.

 

[upstatemike]

I would check to see if the input and the output share a common ground. If so I think you should be ok, except perhaps for the noise level.

What do you think might cause a noise issue? The amp driving the line or the long fun of daisy-chaned twisted pair? I thought the high signal and low impedance would keep me from picking up too much noise on the wire run.

 

[fcwilt]

I would check to see if the input and the output share a common ground. If so I think you should be ok, except perhaps for the noise level.

What do you think might cause a noise issue? The amp driving the line or the long fun of daisy-chaned twisted pair? I thought the high signal and low impedance would keep me from picking up too much noise on the wire run.

That amp is a low cost unit and I don't know what it's noise spec is but it might have too much noise to daisy chain. If you have a pair just try it and see what you think.

 

[upstatemike]

I would check to see if the input and the output share a common ground. If so I think you should be ok, except perhaps for the noise level.

What do you think might cause a noise issue? The amp driving the line or the long fun of daisy-chaned twisted pair? I thought the high signal and low impedance would keep me from picking up too much noise on the wire run.

That amp is a low cost unit and I don't know what it's noise spec is but it might have too much noise to daisy chain. If you have a pair just try it and see what you think.

Unfortunately only have 1 test unit at the moment so I'll have to get another to check the noise. I could stick with 70V distribution but then I lose having a full range volume control at each location and I also liked the idea of everything runnning from the 12V power supply so emergency messages don't quit on me during a power failure. I guess I can put the PA amp on a UPS but that would not run it for very long.

This is paging and HA announcement stuff only so I don't need super high fidelity. (But I guess I don't want stat and noise either)