Altec 604 C diaphragm differences - Help

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Originally Posted by bowtie427ss

Sorry to hear of this. I feel fortunate that i was advised long ago to NOT send working diaphragms or salvageable cones when having anything rebuilt as you will not see them again.

It is also a good idea to tape a note to each component specifying the exact work you want done to it. There's just no substitute for good communication.

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I bear some of the responsibility as I did not send info in both boxes as to exactly what I wanted done nor did I include pre paid return labels. So not entirely bills fault.

My phrams don't have any numbers on them:

http://www.hostboard.com/forums/hbmc...2013/03/28.jpg

http://www.hostboard.com/forums/hbmc...2013/03/29.jpg

These had been sent to Bill for "the treatment". It's possible they got new phrams as well as new cones. The good news is everything should match nicely. The better news is I got some pretty good cabs with them, so all in all, a great deal for $1125. Now if I can just figure out this crossover dilemma...

New phrams would be stamped with a date right where your 391227 is. The one they replaced in my C had a date of April 11 2011 or something stamped there. sorry yours says 511227... I would think it would be a 391 number... anywho I found this one on ebay same as mine pretty much.

I think that 511 number may be from the later era.

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Originally Posted by Old Guy

I think that 511 number may be from the later era.

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Yeah, supposedly the 604s were in the catalogue only in 1957 and were replaced by the 605s in 1958. After that they were still made on a custom basis, mostly for studio customers. No telling what year they came from. When did the 604Es come out?

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Originally Posted by alancohen

When did the 604Es come out?

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1964-ish. They weren't really custom, anybody could get them, they were just not advertised heavily as Altec was pushing the cheaper-to-build 805.

http://www.hostboard.com/forums/hbmc...2013/03/30.jpg

http://www.hostboard.com/forums/hbmc...2013/03/31.jpg

Where does the "D" fit in then? I think it was "C" till 57 and "D" to 63.
My "E" is stamped 64.

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Originally Posted by cradeldorf

Where does the "D" fit in then? I think it was "C" till 57 and "D" to 63.
My "E" is stamped 64.

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As far as I can tell, the Ds were in the catalogue in '57, gone in '58 and replaced with 605s. You could still buy a 604D if you knew about them. I'm guessing they made the "604D" until the "604E" came out. So the 604Ds were 1957-1963 mostly as a special order only since they were not advertised.

Someone just got a deal:

http://www.ebay.com/itm/Altec-lansin...item3f22ab7442

After further review: a 1958 ad that shows 604Ds

http://www.ebay.com/itm/Altec-Driver...p2047675.l2557

I talked with Bill Hayes today, who'll be 90 this July incidentally, and he says that there was never any diaphragm change in the production model of the 604C.

Any differences, he said, would be due to the fatigue of the diaphragms, plus weakening of the magnets. It could also be the crossover(s).

Is the room perfectly symmetrical?