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brianshep 15th March 2012 06:18 PM

altec 1590E input questions
hello all could someone help me with this old altec 1590E it has the 15095A plug in transformer my question is this with the transformer in place can i connect a high level input speaker outputs of a a\v reciever or are the inputs strictly 0.8v the literature says a direct connection of 0.8v or higher is available on tap 1,2 but does that mean line speaker output... thanks sorry for the newb question.

brianshep 18th March 2012 01:39 AM

hmmm no response i will try to

word it a little differently! i have checked and researched all the altec literature and posts that i can find and being much less than an electronics engineer the answer to my question is quite confusing. actually for that matter heck the question is kinda confusing.i really would appreciate hearing from someone who has actually hooked up an altec 1590E and can tell me if using the 15095 plug in transformer can i directly connect high level (speaker) input to input tap 1and 2 or strictly a pre/amp output! like i said the manual is quite confusing as it only mention input impedence and not voltages!is the 15095 transformer a step down transformer that reduces input voltage to 0.8volts or exactly what function does it perform..... i notice they cost more than both amplifiers cost me!!!!

Pano 18th March 2012 01:59 AM

AFAIK, the 15095 is a 10:1 (or 1:10) step up transformer. I'll have a look at the amp specs.

Pano 18th March 2012 02:16 AM

OK, I took a look at the lit. The amp is for commercial sound, I.E. 70V (and higher) distributed systems, you know that - right? Maybe you are using the 30V output tap.

Anyway, the amp will hit full power with an input voltage of 0.8V. Plugging in the transformer would mean that you will hit full power with an input of 0.08V. Not a great idea. "Speaker Level" can mean a lot of things, but that might be about 5 volts average.
You'd want an attenuator before the amp for reasonable volume control. Something in the range of 6:1 would be a good starting point.

Hope that helps.

legarem 18th March 2012 02:26 AM

I have a pair of 1595 and I use them directly without transformers. You don't need the transformers with sources like cd, tuner etc.

bear 18th March 2012 02:27 AM

afaik, you do not need an input xfmr at all. direct in with line level should work fine. I have the 1594 and it is virtually the same amp (I do not use it for hi-fi stuff, btw), and iirc you can connect an RCA jack and use it that way.

If you post the schematic, then it will be easier to comment on how to do it.

Sell the input transformers, unless you need them for a specific purpose.


Burnedfingers 18th March 2012 02:50 AM

I've never used a 1590E, or C, or D without a 15095 transformer. To me it adds isolation and certainly doesn't hurt a thing. Trying to run the amplifier with a speaker output feed is nOT recommended. The amplifier was designed to run with a .775-.800 signal input level.

If you have the transformer then run it. You have nothing to gain by not using it.

Pano 18th March 2012 02:53 AM

O.B., isn't the 15095 a step up tranfo? Or am I wrong about that?

Michael Chua 18th March 2012 04:08 AM

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Originally Posted by brianshep ( question is this with the transformer in place can i connect a high level input speaker outputs of a a\v reciever....

No, the 15095A is not meant for that. It is used to convert your power amp High Z input to 600 Ohms. This transformer is only used in systems working on dBm (0dBm=1mW). For hifi (dBV or dBu), the 600 ohms impedance is a very difficult load for the preamp. I suggest you remove this transformer unless you are using a pro mixer. Those are the ones running on dBm.

To drive your Altec with your AV Receiver Speaker Out, remove the 15095A. Install a voltage divider at the input of the Altec, a 100K to input (#1) followed by 2.7K shunt to 0V (#2). Connect Red speaker wire to 100K and Black speaker wire to 0V. This will lower your speaker output to line input.

Burnedfingers 18th March 2012 06:19 AM

The 15095 or 15095A is a 150ohm mic level or 600 ohm line level to 15K step up transformer. Trying to drive the 1590 with speaker output from your A/V receiver is not a good idea. There is absolutely nothing wrong with the transformer being in the input. Given the resale price of these on ebray you could sell the transformer for a hunk of change. There is strapping information available for bypassing the transformer.

The more acceptable way of doing this is connect a 70 volt transformer 8 ohm side to your receiver and say a 1/4 or 1/2watt tap of the transformer to the input of the 1590. This will drop the level down to a safe one that the 1590 will work with. You can pick a tap that will work fine and deliver a suitable input level.

Since I have had to use these antique pieces for the last 20 yrs in commercial applications I have to ask why in the world would you even want to use this piece of crap? They make a better boat anchor then they ever did an amplifier. I used to scrap them for the aluminum heatsink.

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