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Author Topic: Self amplified speaker/2  (Read 6412 times)

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Online MooreTel

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Self amplified speaker/2
« on: November 18, 2012, 07:47:06 AM »
I'm not that worried about distances as per the other thread on these speakers.

My question is pertaining to the transformer amp.

I can order the speakers (3, 5 or 15 watt) either with or without the transformer, which I can get with outputs of 250, 500 or 1000ma.  I have attached two speakers to a 500ma transformer several times with no issues.  Most of the transformers that I use are the 500ma version.

How many speakers can I put on one transformer of this size?  On the last install I did, I installed a total of 9 speakers on a transformer with 6 taps on it of 500ma each.  The transformer was pricey, but at least I didn't have 9 transformers attached to the power source.
Wilson's Law of Commercial Marketing Strategy - As soon as you find a product that you really like, they will stop making it.

Online telemarv

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Re: Self amplified speaker/2
« Reply #1 on: November 18, 2012, 12:59:06 PM »
A 5 Watt speaker will consume about 225 mW at full power

The Math: Amp = (Watts / 24volts)  + 10% for loss.
Marv CCNA


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Online hbiss

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Re: Self amplified speaker/2
« Reply #2 on: November 18, 2012, 02:14:51 PM »
What manufacturer/part numbers are you talking about? What you are saying doesn't make any sense.

-Hal
I gotta get out of this business...

COMSYSTEC- Phone Systems | paging systems | background music systems | foreground music systems | retail music | restaurant music

Online MooreTel

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Re: Self amplified speaker/2
« Reply #3 on: November 18, 2012, 02:53:11 PM »
These are what I install: http://norelcotele.com/productsByCategory.php?CategoryID=8&SubCategoryID=15

Marv, that sounds about right.  I've installed two 5 watt speakers with a 24vdc, 500ma or 1000ma transformer.

Hal:  Sorry, I must have writing "Canadian", as Marv understood  :022:
Wilson's Law of Commercial Marketing Strategy - As soon as you find a product that you really like, they will stop making it.

Offline silversam

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Re: Self amplified speaker/2
« Reply #4 on: November 18, 2012, 04:08:02 PM »
Dave -

I think the confusion (I felt it too) was because down here when people talk speakers and transformers they're talking about constant voltage (70/25 volt) equipment. With amplified speakers they talk about power supplies, not transformers.

My buddy married a British gal and moved across the pond. He said the hardest part of the move was understanding what the Brits called something that he knew by a different name. It's been 10 years and it still drives him crazy.

Sam

Online hbiss

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Re: Self amplified speaker/2
« Reply #5 on: November 18, 2012, 04:39:05 PM »
Looks like they use the same method to calculate required power as Valcom. Notice the "1/2 power unit, 1 power unit " spec in the description? Someplace there has to be a system design and installation manual that shows all of the products, their power requirements in "power units" as well as the power supplies with their output given in "power units" along with wiring requirements, etc.

So to answer your original question, they make it easy for you. Simply choose a power supply that will supply a number of "power units" equal or more than the sum of all your speaker "power units". There is no need (and indeed it's incorrect) to figure or assume any actual current draw.

This is 24 vdc that powers the internal amps in the speakers. It has nothing to do with the audio.

-Hal 
I gotta get out of this business...

COMSYSTEC- Phone Systems | paging systems | background music systems | foreground music systems | retail music | restaurant music