Is the Altec 9440A amplifier any good?

[rghinton]

I have a used Altec 9440A amplifier in simi-rough condition and it does not work. Does anyone have any experiance with this model of Altec amplifier? How would it work with my Altec speaker system? If it is a good amplifier, I will get it fixed otherwise?????????????

Thanks,
Reed G. Hinton

[RClark]

its a horrible amp--------if you need a place to dispose of it i will gladly send you a self addressed shipping box--------seriously it is an excellent amp by any standards even today-------as good as any amp in its power range and full of features that few amps can compare to------it produces well in excess of its rated power and can even drive 1 or 2 ohm loads safely at full power (400 per ch) if the power switch is in the 40% position

[rghinton]

Thanks Richard. I blew the dust out of it and have been listening to it all afternoon on junk speakers, just in case.

Reed G. Hinton

[Blu]

Richard,

Are you the same R.C. from Autosound 2000?

Cheers!

Charles
p.s. - appologies to Reed for the minor detour.

[RClark]

charles-------yes------30 years ago i used to be a Altec commercial contractor-------its how i got my start in audio--------i have a HUGE collection of Altec stuff that goes back to the 40', 50' and 60's--------i love collecting and restoring the old gear--------its a passonate hobby............RC

[RClark]

reed-------what is your concern with the amp????------have you had some sort of problem with it------if so give me the symptoms and perhaps i can help you------i have fixed quite a few of them in the last 25 years.........RC

[rghinton]

Thanks for the reply Richard. I bought the amplifier with the condition that shortly after the amplifier was turned on that it would go into oscillation and the meters would peg. The amp was dirty and looks rough so the first thing that I did with the amp was to blow the dust and dirt out of the amplifier. I was going to fix whatever was wrong with the amplifier. When I tried it for the first time yesterday, it seemed to be OK. I listened to it all of yesterday and today while working on the house. It seems to be working fine. I always wanted to try using an Altec 9440A. I just wished that it looked a little better. I think that it was used as a PA Amp and was moved around a lot.

[RClark]

both meters peg??????-------there is very little that is common to the signal path of both channels on that amp-------in fact nothing that i can recall other than the DC latch detect and that wouldn't cause such a symptom----its hard to imagine how it could have an identical problem in both channels unless it was fed a mono signal----odds are just against it------perhaps there was something wrong with the system it was taken out of that was causing it to oscillate ???????-----there were several versions of that amp and some of the very early ones were prone to problems related to stability-----they had blue meters but there were not many made--------then there were the ones with purple meters that were more stable but occasionally got noisy------by the time they recieved white meters they were almost bullet proof------it is pretty easy to retrofit them to the final version------do you know what version driver boards you have????-----it is marked on the back of the amp as well as stamped on the boards---------i can tell you for sure that there is a cap in the feedback circuit on each driver board that needs to be replaced on all of them------i have quite a few 9440's and this particular cap always loses its value over the years and causes a considerable loss of low frequency response...........RC

[marcuswilson]

Reed,

I have found some amplifiers sensitive to 'dust' and the moisture it contains. If the amp had a lot of dust on the circuit boards, this may have caused problems.

Also, if it had not been turned on for a long time, the electrolytic capacitors may have 'unformed' and their value can go down to almost 0 as well as being very leaky.

On an old amp it is best to replace all of the electrolytic capacitors (especially tantalum ones) as they deteriorate after 5 to 10 years.

[rghinton]

I am listening to the 9440A in my spare time. I have been playing it all day long for the past few days. I am using a pair of junk test speakers at the time since I have not yet built enclosures for my Altec speakers. The amplifier is getting better. I noticed on the first day that there would be a fairly loud pop in both speakers when the amp would come on or when I would shut it off. This no longer happens. There was also a fairly loud buzz out of both speakers all of the time. This has diminished somewhat over the past couple of days. I realize that changing some of the capacitors may fix my buzz problem. I may also have a grounding problem. When I turn the level controls all of the way down, the buzz is almost gone. There is less buzz if I do not connect the ground on the 120V AC power. When using the amplifier with the Altec speaker systems, in a dead quite room, with no input, can you hear any hum or buzz with the volumn control all of the way up? The input may have to be terminated for this test. Years ago, I used a Nikko Alpha 650 on my Altecs and the Nikko amp was dead quite. I would have it terminated into my preamp with its level controls all of the way down but the level controls on the Nikko were all of the way up. I could hear nothing, no buzz or hum. I would not know if the amp was on or off without looking at the amp. The Nikko was 300 Watts per channel and weighed 61 pounds. I have never heard a quiter amp. I hope that the 9440A is also that quite and sounds as good as the Nikko did. My 9440A has the following:

Control Board 27-01-044590-6

Output Board 27-01-044591-5

Driver Assembly Board 27-01-44592-11

Which capacitor in the feedback circuit should be replaced?

Where may I find schematics of the various versions? I have Altec's 9440A Operating Instructions which has schematics but it does not show the various versions.

Thanks for all of the help.

Reed G. Hinton