Altec 9440A?

Tyimo · 27th November 2006, 07:52 PM

Hi!

Has somebody any info about the legendary Altec 9440A amp?
Maybe a schematic?????

Greets:

Tyimo

tomtt · 27th November 2006, 10:06 PM

scroll down-about half way...

http://alteclansingunofficial.nlenet...ers/index.html

Tyimo · 28th November 2006, 05:00 AM

Hi Tomtt!

Thanks for the link!

It is a goldmine!

Greets:

Tyimo

Original Burnedfingers · 28th November 2006, 10:43 AM

The 9440 is a great sounding amplifier. I owned about 10 of them over the years and at one point had 5 of them in my theatre rack running mono bridge at 800 watts a channel. The bad thing about them is that parts are getting hard to find. You don't want to try to use any ECG or NTE parts in one or you will let the smoke out. The driver transistors are not going to be found anymore so this will make a problem.

Tyimo · 28th November 2006, 11:27 AM

Hi Burnedfingers!

Quote:

The bad thing about them is that parts are getting hard to find.

Yes. But I am still dreaming to buy or to clone one......

Tyimo

bobd53 · 8th April 2009, 08:54 AM

Thanks to tomtt for the link. Unfortunately, my 9440A is several years newer than those documents (13th week of 1982) and also has a label saying the following:

Quote:

THIS APPARATUS
HAS BEEN DESIGNATED
FOR MIL SPEC MANUFACTURE

There's an additional relay not in the 1975-1977 documentation as well as a two-pin connector (with a pair of 1/4" male quick connects) located between the input jacks and the output binding posts. The relay and that connector, along with a small terminal board containing a transistor and a couple of resistors, are wired into the circuit with the thermal switch between the E18 terminals on the output boards. At first I couldn't get the output relay to pull in. I had tried leaving the pins of the extra two-pin connector open as well as shorting them together after power was already on. (There was about a quarter of a volt between the pins when open and one pin goes only to one end of a 510-ohm resistor, so I figured it was safe to try shorting them.) I later discovered that leaving the pins shorted when power was applied would allow the output relay to energize. The additional relay seems to form a latch requiring a power removal for reset if the short is removed from the connector.

Does anyone here know anything about those changes? I have no idea if they're custom for MIL SPEC or if they were standard in later production units.

Original Burnedfingers · 8th April 2009, 10:45 AM

Can you post a picture? I don't remember an additional relay.

bobd53 · 8th April 2009, 10:18 PM

Here are pictures of the extra connector, both relays, and the label on the front panel:

If you scroll to the bottom of the picture of the relays, you can see the terminal board with a transistor, two resistors, and a diode.

Six wires (orange, blue, grey, white, red, and green) go back to the heatsink assembly and a seventh (violet) goes from the relay's normally-closed contact to the transistor on the terminal board.

Original Burnedfingers · 8th April 2009, 11:35 PM

I looked at one that was built at the very last of the production run and it has no added circuitry or relay. Based on your pictures it looks like something that someone has added. If it were me I would remove the added parts so it reverts back to the circuit as shown on the schematics.

bobd53 · 9th April 2009, 04:15 AM

Thanks for the replies.

I was going to do that before I figured out that leaving the two pins of the extra connector jumpered together makes everything operate normally. The workmanship of the mods leads me to believe it was done by Altec, perhaps in their prototype lab. It really looks like it was done during manufacture rather than later.

The cooling fans, on the other hand, were definitely added by someone else. I'll be replacing them with a set of Whisper fans before I put this beauty on the market. I'd love to keep it, but I need the money and my Marantz 510M is a better fit for my home system, anyway. I originally acquired the 9440A so I wouldn't need to take the 510M out of my living room every year for a two-day outdoor event where I was providing sound reinforcement with 4 Altec A-7 Voice of the Theater speakers (also for sale now), but I never got around to making it work before I stopped running the event.

On the subject of selling the 9440A, I haven't decided yet between eBay and Audiogon or on how much to ask. Any thoughts?

27th November 2006, 07:52 PM	#1
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Altec 9440A? Hi! Has somebody any info about the legendary Altec 9440A amp? Maybe a schematic????? Greets: Tyimo

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28th November 2006, 05:00 AM	#3
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Hi Tomtt! Thanks for the link! It is a goldmine! Greets: Tyimo

28th November 2006, 10:43 AM	#4
Original Burnedfingers diyAudio Member Join Date: Nov 2002	The 9440 is a great sounding amplifier. I owned about 10 of them over the years and at one point had 5 of them in my theatre rack running mono bridge at 800 watts a channel. The bad thing about them is that parts are getting hard to find. You don't want to try to use any ECG or NTE parts in one or you will let the smoke out. The driver transistors are not going to be found anymore so this will make a problem.

8th April 2009, 10:45 AM	#7
Original Burnedfingers diyAudio Member Join Date: Nov 2002	Can you post a picture? I don't remember an additional relay.

8th April 2009, 10:18 PM	#8
bobd53 diyAudio Member Join Date: Apr 2009	Here are pictures of the extra connector, both relays, and the label on the front panel: If you scroll to the bottom of the picture of the relays, you can see the terminal board with a transistor, two resistors, and a diode. Six wires (orange, blue, grey, white, red, and green) go back to the heatsink assembly and a seventh (violet) goes from the relay's normally-closed contact to the transistor on the terminal board.

8th April 2009, 11:35 PM	#9
Original Burnedfingers diyAudio Member Join Date: Nov 2002	I looked at one that was built at the very last of the production run and it has no added circuitry or relay. Based on your pictures it looks like something that someone has added. If it were me I would remove the added parts so it reverts back to the circuit as shown on the schematics.

9th April 2009, 04:15 AM	#10
bobd53 diyAudio Member Join Date: Apr 2009	Thanks for the replies. I was going to do that before I figured out that leaving the two pins of the extra connector jumpered together makes everything operate normally. The workmanship of the mods leads me to believe it was done by Altec, perhaps in their prototype lab. It really looks like it was done during manufacture rather than later. The cooling fans, on the other hand, were definitely added by someone else. I'll be replacing them with a set of Whisper fans before I put this beauty on the market. I'd love to keep it, but I need the money and my Marantz 510M is a better fit for my home system, anyway. I originally acquired the 9440A so I wouldn't need to take the 510M out of my living room every year for a two-day outdoor event where I was providing sound reinforcement with 4 Altec A-7 Voice of the Theater speakers (also for sale now), but I never got around to making it work before I stopped running the event. On the subject of selling the 9440A, I haven't decided yet between eBay and Audiogon or on how much to ask. Any thoughts?