Quote Originally Posted by GM View Post
Can't really comment about the luster other than of the grand total of two pairs I've seen up close, the first pair AFAIK to arrive at the local distributor was low luster and the other pair at CMC Stereo several years later looked like wet Formica, but I knew they used Pledge by the case to make everything sparkle.

Don't know how long they made the ultralights, just that the last pair I bought was in '94 and that they were in stock at the time, though later I found out that they no longer actively supported Altec, having switched to B0$3 prosound as their main line, so could have been NOS.

A chart of compression drivers done some years ago by the late Bill Eckle shows them only being offered in the 802G, 902A or through the '83 model year though: intro

GM
This page (from Bill Eckle's website) would seem to support the fact that the lite diaphragms were the stock diaphragms in the 902A's as well as the 802G's which means their production run was at least from 1976 through 1983. Altec

Bill Eckle lists his opinions on some of these drivers--he really seemed to know his stuff for the most part (other than an occasional inaccuracy--dates, etc.) and this page made for some interesting reading. A couple of examples:

(about the 416-8B) "All units built on 16" frame. Has improved Alnico magnet structure. Best of all 803-416 woofers . Brought back in late 1980s for a short period. Black in color."

(about the 902A) "Entirely new driver with ferrite magnet. Has the same radial phase plug as 802G.
Replaced both 802 and 806 drivers. Is thinner driver than older units. Originally built with very light and fragile diaphragm. Sounds fabulous."

(about the 802G) "Has new radial phasing plug, improved magnet structure. Originally equipped with very light diaphragm. Improved overall performance, last Alnico magnet."

(about the 902T) "Same as 902-8A, but has diaphragm loading cap installed inside the rear cover to stop diaphragm over excursion on 500 Hz crossovers. Doesn't sound as good as 902A."
"The diaphragm loading cap as explained in 902T driver, prevents over excursion of the diaphragm at lower H F horn limits. While it prevents diaphragm failure, it also slightly reduces the naturalness of H F sound quality. Loading caps have come and went thoughout the years. Certain variants of drivers have been produced both with and without them "

Interesting to see the evolution of some of these drivers on a chart. As far as his opinions--of course everyone has/is entitled to their own opinions but I would say I agree with many of his....

AB, thanks for providing the part number for this diaphragm (23744), now that I see it, I recognize/remember it.

I'd probably go with the GPA 34647 diaphragms if I ever need replacement diaphragms for my 19's (right now all my original diaphragms still work/sound great--and I don't play them excessively loud so hopefully the diaphragms I have will "hang in there"). According to Bill at GPA (when I inquired about this), even though the 34647's may not be exactly identical sounding to the original 23744's (when the 23744's were brand new), they are comparable in performance (with a higher power handling capacity) and a brand new pair of 34647's should sound noticeably better than a 30 year old pair of 23744's. Bill/GPA has done work for me before (recones for my old P.A. speakers--421 woofers) and has never steered me wrong......