Altec 1590C

[Ed LaFontaine]

I have found some Altec 1590C amplifiers available. Are they worthy of restoration? Are they a source for parts?

I'm asking for your comments before I call them trash or treasure.

Thanks

[Ed LaFontaine]

I continue searching and found this link:

http://www.lansingheritage.org/image...90e/page01.jpg

[Original Burnedfingers]

Ed,

The 1590 series is a commercial amplifier rated at 200 watts. It will drive a 25volt, 70 volt, or 100 volt load. It is not suitable for serious listening in the home environment but rather a modest amplifier for a civic center or mall.

Its heat sinks would make a nice beginning for another project. I've repaired more than my share of this animal. The last two I had on hand I gave away.

[Wavebourn]

I have one, I want to experiment with it using power FETs and vacuum tube phase splitter. It may be excellent for bas guitar in such configuration.

[anatech]

Hi Wavebourn,

I have one, I want to experiment with it using power FETs and vacuum tube phase splitter.

If you're going to do that, why not just buy a Counterpoint?

-Chris

[Wavebourn]

Originally posted by anatech
Hi Wavebourn,

If you're going to do that, why not just buy a Counterpoint?

-Chris

Why to buy?

[djk]

It would be a waste of time and money to use FETs to re-do an Altec 1590.

TO-3 FETs are quite expensive (the heatsinks are drilled for TO-3). The output transformer core is not sized for full-range hi-fi use, and does not have an air-gap in it. The B+ is quite low for much of anything else, no center-tap.

Some old PA monsters are a good source of parts for a hi-fi amp. In my mind, the Altec 1590 is not one of them. You could knock two of them together to get enough ±V for a 40~50W output stage (direct coupled), and enough power for a 5~7 channel HT rig. I would go BJTs for the outputs though, maybe something like the hybrid in the latest AudioXpress.

The 200W STROM from this same vintage has twice the B+, and a center-tapped transformer. When used with a full-wave bridge rectifier it will give ±75V for a 200W/8R, 350W/4R stereo amp.

[anatech]

Hi Wavebourn,

Why to buy?

If you are going to go to all that work, you might end up with something like a Counterpoint. It would be cheaper to just buy one.

I second the use of BJT outputs. My personal belief is that tube front ends will not drive mosfets properly. You'll end up with something that may almost sound okay.

-Chris

[Wavebourn]

Instrumental amp with tubes and FETs sound better, much better. Counterpoint's design sounded like a poor BJT output, and it was unreliable (I don't mean redesigned version, when he run a service company). Altec transformers are excellent for a bass guitar project, it was specified for 200W from 20 Hz, so will be fine for 41 Hz. Just a plate+filament transformer is needed to power a phase splitter. Also, it has an octal socket on the chassis. I see no problems with TO3 sockets, there are enough space for flat transistors.

[djk]

If your serious about trying this, I should offer you my stock of TO-3 FETs. I am never going to use them for anything. Same IRF part used in the Nelson Pass Citation 12 mod.