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http://alteclansingunofficial.nlenet.net/proelectronics/proamplifiers/index.html
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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.
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:
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.
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.
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.
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.
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?
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?
I went thru all of my Altec service information that lists the different modicications and fixes that were necessary over the years and there is no mention of what you have there. To me it still looks like something someone added but not something that ever came out of the R&D lab. Altec documented everything and being an Altec dealer until they went belly up we have had numerous occasions to meet with different engineers over the years.
The 9440 had a cover that went over the heatsinks which was set up for two fans. It was drilled and tapped to accept the 4 mounting screws. Some owners and or installations didn't use the fans. Most that I have repaired over the years have had the two fans that mount the the back of the cover.
Getting to the nitty gritty here... the Altec is a far better sounding amplifier than most that are on the market today. To bring it back to its former glory the caps on the driver boards as well as the power supply caps will need to be changed. A nice little trick is to add a 100mfd cap and a .1 and parallel with the power supply caps. This tightens up the low end and makes a difference in the mids and highs. DJK is the expert on the 9440's and can supply more modification information.
If I lived closer I would gladly purchase the 9440 from you just to have another on hand. What it is worth? Well first get rid of the abortion circuitry that doesn't belong there. Price wise I have seen them go from $200 in so so shape to over $600 for a mint one. If it were me I would let the 510 go down the road.
The 9440 had a cover that went over the heatsinks which was set up for two fans. It was drilled and tapped to accept the 4 mounting screws. Some owners and or installations didn't use the fans. Most that I have repaired over the years have had the two fans that mount the the back of the cover.
Getting to the nitty gritty here... the Altec is a far better sounding amplifier than most that are on the market today. To bring it back to its former glory the caps on the driver boards as well as the power supply caps will need to be changed. A nice little trick is to add a 100mfd cap and a .1 and parallel with the power supply caps. This tightens up the low end and makes a difference in the mids and highs. DJK is the expert on the 9440's and can supply more modification information.
If I lived closer I would gladly purchase the 9440 from you just to have another on hand. What it is worth? Well first get rid of the abortion circuitry that doesn't belong there. Price wise I have seen them go from $200 in so so shape to over $600 for a mint one. If it were me I would let the 510 go down the road.
Whoever mounted these fans removed the perforated metal from the holes first, so removing the fans would leave gaping holes. The fans move about 3 or 4 times the air that the recommended fans would move and are way too loud, so a pair of Whisper fans are in order to cover the holes and move air more quietly.
A 9440A in poor condition and not working just sold on eBay for $175.54 plus shipping (item # 270368286207). If I wasn't broke I'd have bid on it myself.
I'm the original owner of the Marantz so I'm kind of attached to it. At least two of them have sold for over $1500 in the past month on eBay. I would think a fully functioning 9440A is worth at least as much as the Marantz. Of course, someone else has to think so in order for it to sell at that price.
If I can get all four of the A7s sold, I might just hang onto both power amps.
A 9440A in poor condition and not working just sold on eBay for $175.54 plus shipping (item # 270368286207). If I wasn't broke I'd have bid on it myself.
I'm the original owner of the Marantz so I'm kind of attached to it. At least two of them have sold for over $1500 in the past month on eBay. I would think a fully functioning 9440A is worth at least as much as the Marantz. Of course, someone else has to think so in order for it to sell at that price.
If I can get all four of the A7s sold, I might just hang onto both power amps.
Thanks again, tomtt.
Actually, I had already found those pages while researching the components in my Voice of the Theater speakers.
Lately I've been combing eBay for some 15095A transformers for balanced inputs on the 9440A. (I want 600 ohm inputs instead of 15k ohms.) So far they've been going for about 3 times what I'm willing to spend. I noticed in the manual that the specified transformers are 15335A with a caution not to use the 15335 without the "A". I'm assuming the same would apply to the 15095A vs. the 15095, but does anyone here know the difference between the A and non-A versions?
Actually, I had already found those pages while researching the components in my Voice of the Theater speakers.
Lately I've been combing eBay for some 15095A transformers for balanced inputs on the 9440A. (I want 600 ohm inputs instead of 15k ohms.) So far they've been going for about 3 times what I'm willing to spend.
I noticed in the manual that the specified transformers are 15335A with a caution not to use the 15335 without the "A". I'm assuming the same would apply to the 15095A vs. the 15095, but does anyone here know the difference between the A and non-A versions?
The difference between the 15335A and the 15335 is in the shielding and the grounding. The 9440 will work fine with a 600 ohm source into the primary of 15335A. Altec states on page 3) of the 9440A manual that the 15335A is the only transformer that can be used.
As DJK has politely mentioned there is going to be a gain problem trying to use the 15095A. I suggest that you follow this advice because it is based on actual knowledge and usage of the Altec product by both Dennis and myself.
As DJK has politely mentioned there is going to be a gain problem trying to use the 15095A. I suggest that you follow this advice because it is based on actual knowledge and usage of the Altec product by both Dennis and myself.
quoteo you have any idea of how much gain the 9440A will have with 600 ohm transformers installed?
If memory is correct the 15095 is a favorite of those owning MC phono cartridges to get a good step up in gain.
I happen to have a pair or two of the 15335A's if you want to pay me what they are worth.
o you have any idea of how much gain the 9440A will have with 600 ohm transformers installed?If memory is correct the 15095 is a favorite of those owning MC phono cartridges to get a good step up in gain.
I happen to have a pair or two of the 15335A's if you want to pay me what they are worth.
I had been figuring that since the mixer had a transformer on its output from single-ended high impedance to 600 ohms balanced (such as the Bogen TL-600), then a transformer at the other end that reversed the process would achieve the same level as a direct high-impedance connection (or even lower considering the losses in the transformers.) What I hadn't counted on was that the Bogen MXM-A mixer can produce 20 volts at high impedance and 4 volts into 600 ohms, substantially higher than the usual "line level". I haven't checked my other mixers but happen to have the MXM-A manual handy.
I had also been considering a pair of 15356A transformers with 620-ohm resistors added across their secondaries but was worried that I wouldn't have enough gain. I see now that it wouldn't have been a problem, but I also see that the 9440A manual does make reference to the 15k-ohm balanced input being fed by a 600-ohm line.
What figure did you have in mind for a pair of 15335A transformers shipped to Baltimore?
I had also been considering a pair of 15356A transformers with 620-ohm resistors added across their secondaries but was worried that I wouldn't have enough gain. I see now that it wouldn't have been a problem, but I also see that the 9440A manual does make reference to the 15k-ohm balanced input being fed by a 600-ohm line.
What figure did you have in mind for a pair of 15335A transformers shipped to Baltimore?
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