A 7-500 question

[Bill F777]

I was working with some A7-500 speakers, and they had 421-8H musical instrument speakers installed in them. Did altec use the 421-8h woofer in the A7-500, or do you think this was installed as a replacement woofer?

Thanks!

[Old Guy]

The 421 isn't factory- it was used in the Musical instrument version however with an 808 driver, but that isn't an A-7 500. It does have the 511 horn but an 800 hz (later 1200) hz crossover.

[dgwojo]

Sounds like a model 1208b, it came with a 421/808/511b/N809 combo, these were made around 1975, Dave.
Altec 1208B

[Old Guy]

I think the 1208 was made about72-78. I bought a pair in '73. Or at least a pair with the 421/511/808 combo.

[gamalot]

I've said this before but back then, sound engineers could order just about any load set they wanted along with a specific cabinet.

I think it is highly possible a rock band or music hall could have ordered the exact load set you have in the A7-500 cabinets.

What is even better these days is that you can re load them to what ever it is you desire and to fit your own personal application.

So much of the Altec innards are interchangable that the sky is no limit depending on where you decide to use your cabinets.

Dwojo and many here can advise you on what might work best for the room and type of music or setting you have in mind.

There really is no telling what might have been originally loaded in them but there certainly is alot of info on what works very well for your given needs.

Chioces might include 500, 800 and 1200 Hz XOs,
803, 416 and 515 woofers and just about any of the 800 or 900 series HF drivers.

Tell us where and how you plan to use them and you are sure to get many good ideas.

Gary

[Old Guy]

A simple check would be to check the date codes- if the woofs are newer they are almost certainly replacements.

If the dates all match...

[Bill F777]

Where do I look for the date codes? I will get them, and post them. Thanks!!

[Old Guy]

look for a stamped number 391xxx. 391 is Altec, the rest is date code. Prolly will have to look around on the woofs and remove the back caps on drivers. Use caution with screwdriver close to diaphragm.

[Bill F777]

Got the speakers apart, the date on the woofer is 78, it had the date stamped on the basket of the woofer. The horns are 511b, the horn drivers are 908-8a. The cabinets did have the voice of the theatre decals on the sides. They did not have crossovers in them, when I got them, and it looked like they never had them. They had a terminal strip on the back of the cabinets, labeled mid and high, mid to the woofer, high to the horn. Just wondering if they were built that way, the person I bought them from said they were A7-500.

[Old Guy]

That isn't an A-7 500 configuration.

421/808 (later 908) is the standard load for what we called the MI version. It was for PA use.

78 is about when Alnico changed to ceramic on the HF's, so that could well be the factory load.
The 908's can be converted to 902- se the loading cap thread.

The 421 is best sold or swapped for a more "hi-fi" woofer for home use.