908 0r 902?

[voice of the theater]

Nice speaks! I have never heard those.
Actual testing has been done, and a lot of ears here prefer the drivers you have with the end caps and felt. I'll let others comment.
Loading caps originally were used to limit fram travel in high power applications. I suspect Altec did cheap out in this instance trying to keep costs down.

I've read here before in posts by Old Guy and others that removing the loading cap and putting felt on the back cover was an upgrade for home hi-fi use (if you're not looking for "high power" protection). I guess I never understood what a loading cap really was/looked like. I knew my 902's didn't have a back cover as was customary in Model 14's, but didn't understand that what they had instead was in fact a loading cap. If I had known that it was a loading cap then I may have been able to put 2 plus 2 together and realize that I could upgrade them by removing that cap and installing a rear cover with felt...... As far as Altec's motivations for using a loading cap on the Model 14's instead of a back cover, it may not have been entirely a cost oriented decision IMHO. One of the things they boasted about with the Model 14's was the power protection circuitry. It was something that the Model 19 and 15 (it's predecessors) didn't have. I think they may have been genuinely concerned that very powerful receivers and amplifiers were becoming popular for home stereo use--and the prices on them had dropped so a lot of "average Joe's" who weren't even "audiophiles" were using powerful receivers for their home stereos. Altecs, of course, were extremely efficient speakers that could easily be destroyed by a powerful receiver/amp, so I'm thinking the power protection circuitry and the loading cap both appearing on the Model 14 may not have been a coincidence. Just a theory, of course..... However, they could have included a loading cap AND a back cover so eliminating the back cover altogether did save them some money

As far as the transition from alnico to ferrite, I think I heard somewhere that alnico was much harder to obtain at that time (and was very expensive). However, I'd like to think that Altec may not have been (entirely) negligent in switching to the 902-8A and 416-8C without making any mods to the cabinets/crossovers in the Model 19. I would hope that when the 902-8A and 416-8C were in the design/development stage, their goal hopefully was to design ferrite drivers (replacement drivers for their alnico "counterparts") that would perform as well or better than their counterparts in the same/similar applications (possibly including working as well or better with the same crossovers/cabs/etc.). From what Ron and Bowtie are saying, maybe they succeeded with the 902-8A but were not so successful with the 416-8C? Just a theory again, and yes, I'm going out further on a limb with this second theory......

FWIW, IMO&E 902 wins hands down for HF extension......

OK, you and Ron (who both seem to really "know your stuff") both prefer the 902-8A over the 802-8G. Do you guys mean the 902 with the light diaphragm, or with the 34647 diaphragm? Or do you mean with either diaphragm the 902's "beat" the 802-8G's with light diaphragms. I'm not sure when Altec stopped making the light diaphragm ( I read somewhere maybe here it was by the late 70's or 1980?), but by 1981 they had definitely stopped making them (maybe earlier). My Model 14's have AFAIK the original diaphragms with a 1981 date code that matches the year of the drivers and cabs, and they are 34647. Both pair of my Model 19's (from 1976 and 1978) have light diaphragms (23744). Anyways, I have said here before that the 902/Mantaray combination on my 14's rivals the 802-8G/811b combination on my 19's IMHO. However, even though they rival them, if I had to pick an overall favorite, it would be the 802-8G/811b combination. It sounds "warmer" to me for lack of more precise terminology. However, probably not a fair comparison as my 902's don't have a back cover with felt like my 802-8G's (and also don't have the light diaphragm that my 802-8G's have).

So, does anyone have some kind of description as to what kind of improvement I'm likely to hear if I remove the loading caps on my 902's and install rear covers with felt? Will it be like a toothpaste ad--will they be cleaner and brighter, warmer, or roll off at a higher frequency--any or all of the above? I'm seriously considering buying a used "early" pair of 902's with light diaphragms, and doing three experiments.
1) take their back covers and install them (with felt) on my 902's (in my 14's) after removing their loading caps to see how the sound "improves".
2) After listening to this upgrade for several days, then swap out the light diaphragms on the used 902's that I've bought with the 34647's in my 14's and seeing how that "improves" the sound.
3) Removing the 902's (now equipped with light diaphragms and back covers) and installing them into one pair of my Model 19's too see how I like them compared to the 802-8G's. If I like them better, I'll keep the used 902's I just bought--and start looking for another pair for my second pair of Model 19's. If not, I'll sell the used 902's I just bought but I will sell them with 34647's installed and loading caps, and keep the rear covers and light diaphragms for my Model 14's. I'd of course, be willing to sell them at a loss on Ebay or wherever to compensate for the fact that I bought them with light diaphragms and rear covers and sold them with 34647's (providing I like the light diaphragms better in the 902's) and loading caps without rear covers......

If I prefer the 902's in my 19's over the 802's, I know I'd have two pair of Model 19's that are kind of "Frankensteins" at this point--Ferrite 902's with Alnico 416-8B's, but I want what's going to sound the best and If there's a way to get not only my 14's to sound better but even my 19's, I'm all ears guys! (and thanks for any info/advice from anyone here). I'm thinking even if I replace the 802's in my 19's with 902's, I'll most likely keep the 802's so I can return my 19's back to stock down the road if I want to. However, if the improvement is drastic, I can't say I'd rule out selling the 802-8G's. I guess I'd have to think about it--how important to me is the ability to switch them back to "stock" condition--especially if the 902's end up being a significant upgrade in sound......

BTW, Badtoby, I feel like I'm hijacking your thread but since you already had the drivers identified that you requested, I guess this may be useful info for you too. If I do these three experiments (I most likely will soon--hopefully after getting a little more "infopinion" here), I'll report the results in this forum.