Need some help [telecom]

Hello all,

I am a bit stumped with the age of the equipment and the serious lack of any docs. Like it zero docs.

All I have is the following:

ITT Terryphone C23047 0100 Amplifier.

Connected to multiple speakers that are labeled D31201-0500 VRC8 with a multi-tap Txfmr L50411-0010.

What I have determined is that the Amp is a 100 Watt unit.

What I can't find is this at 25v 70v or 100volt.

The only reason I think it is a 100 Watt unit is the 0100 in the part number. However it could mean 100 volt system.

Can anyone shed some light on this. It is not for repair of the system that is rapidly going away, rather it is to determine the size and voltages of a new Amplifier that is to be installed.

I hate shooting in the dark. With the amount of dark I have right now any glimmer of light would be a blessing.

Please respond.



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From: ABLE1 To: Sent: Tuesday, May 31, 2011 8:04 PM Subject: Need some help [telecom]

Teletronics has one for sale


ITT : Terry Phone : C23047-0100 Amp

100 Watt Solid State : Refurbished Grade A

Mark L. Smith

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Mark Smith


Thanks for the response.

However I am NOT looking to replace a 30 - 40 year amp with another 30 -40 year old amp.

I was more interested if it can be determined from the info supplied if the unit is working on 25volts or 70.7volts.

Presently that information is not available and was hoping someone knew the answer.

Thanks again.


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Probably all of the above. The output transformer has multiple taps. It's 100 watts at 25v on the 25v tap, 100 watts at 70v on the 70V tap,

100 watts into 8 ohms on the 8 ohm tap.

Are the transformer taps labelled at all?

What is the amplifier driving? Measure the load impedance with a bridge, or open up one of the speakers in the chain and see what's inside it.

What is the amp driving? Which taps on the transformer are being used?


Reply to
Scott Dorsey

That is the problem, The terminals are not labeled. Wish they were.

Was hoping to find info on the speaker numbers.

I have to assume that it is 70.7volts. It seems the most logical. Have not been given the green light as yet to replace the amp.

I plan on installing a Bogen 100 Watt Amp, it has taps for 25 and 70 volts. I could play it save and connect to 25volts and test and if output is surprisingly low the jump up to 70volts. Shouldn't hurt any thing at


Thanks for any input.


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What do they look like? What continuity do you measure between them?

Why not look at the transformer in one of the speakers and see what the primary is set up as?


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