908 0r 902?

[Earl K]

Does this phragm have lead in conductors "under" the hub, and "push on" terminals?

> Yes ( to both ) / plus the mounting ring is modern plastic ( ie; not phenolic ).
> The pic ( I posted above ) is the FR of "SkyWaves" 902-8B(s) which are loaded with 35480 diaphragms ( minus loading caps ) .

[voice of the theater]

It's been my understanding based on posts here from Altec employees that production of the lights ceased around '78 or '79. It would certainly stand to reason that some early 902's could have been equipped with them. I've not personally encountered any that made it this far east.

Makes sense. My 902-8A's have a 1981 date code and the 34647's inside also have the 1981 date code. RonSSS, what are the date codes on your two pair of 902-8A's with light diapragms (and what are the date codes on the frams)?

The 35480 diaphragm is purported ( by some ) to be a new style equivalent to the older, "light-weight" 23744 . This ( 35480 ) diaphragm is typically found within 902-8B(s) under a loading cap .

Numerically ( obviously ), it "seems" to follow the 34647 in the timeline , making it hard to logically pin-point when ( & why ) the 35480 was introduced .

Great info--I'd never heard of that diaphragm. Sounds like we need a diaphragm reference chart for our library....

[Earl K]

> Here's a historical tidbit .




> These tabulation blocks were guidelines for the employees winding voice coils .

> This enlargement ( taken from a tiny eBay pic ) was originally posted by a seller who was selling off her Moms estate ( who had been a long-time coil-winder at Altec ) .

> Hard to see , but with enough scanning of the middle guideline, one will see that the difference between the 21597 diaphragm ( 802-8D ) & the 23744 ( 604-8G ) was the presence ( or absence ) of the epoxy glue bead found inside the coil former .

> The 34647 ( in the top tabulation block ) , carried over this construction protocol ( of leaving out the epoxy bead ) .



> BTW , that bottom tabulation block is build info pertaining to voice-coils for woofers .

[gearfreak]

Tried to do the quote thing like you did

The Quote thing... to obtain this separatation
a) 'reply with quote' (this shows you the square brcket formatting)
b) chop it up into as many section as you like, whereby each section begins with QUOTE in square brackets and ends with /QUOTE in square brackets (the latter as seen peeking through in your post)
c) insert your comments, in between the sections, as this one is.

I'm too f'n stupid to figure it out I guess.

* You will see in the initial 'reply with quote' that it includes the user name and some id. e.g. =gearfreak;1837453 or =RonSSS;1837323
You can discard this if you like, or leave intact and copy as part of the beggning (no slash) quote in square brackets at each section.

[RonSSS]

I'll take one apart this evening....watch me be wrong! ha!
Oh, and what does the date code look like?

Ron

[Sundown]

Hi fellas new guy here; love the message board.

Going by this objectively I have a graph at home that shows the 802 8G freq response to the very similar to the 902 w negligible Off axis spread in the upper freq. when I get home I'll post it.. Actually been a while since I last looked at it. Personally I don't the diaphragms in more recent models have any real difference. The old ones on the other hand is a rabbit hole one should be ready for a long free fall

Personally I like the 802 8G and that could be from my many years of guitar and using alnico pickups. Both are excellent drivers and one isn't really better than the other IMO . It's pretty much pick your poison.

[Altec Best]

That said, low XO's are where the removal of loading caps and damping the covers really makes the most difference. At 1.2k or above, i'd probably just leave the caps in place. It's an easily enough reversed mod.

Actually i think the loading caps serve a better purpose at Lower XO points.Especially at 500 Hz. Loading caps were designed to protect HF diaphragms at lower crossover points at High volumes.The rear covers and felt seem to have a smoother response IMO.I prefer the felt myself.Since I don't run my drivers at movie theater volumes for hours on end.They really aren't needed in my applications.The loading caps sole purpose was to protect the HF diaphragm from over excursion and damage.

Read Jeff Markwarts experiments on the loading caps. Altec Compression Driver Rear Loading Caps

But, i encourage you to give it a try and see what your own ears say.

Bowties advice here is all you really need.You can't go by other peoples opinions on how something sounds.You will have no better opinion on how something sounds than your OWN !!!

BTW- I personally like the 802G's better with my lite Frams !! But the 902-8A originals sound fabulous too.They are so close it could be a toss up.But in my experiments (blind) i picked the 802G's.. To each his own !


My 19's came with Alnico drivers.The odd thing about my 802-8G's is they came with the old style round rear cover with the screw down terminals.And a white ink stamp of 033952.

[RonSSS]

Hi fellas new guy here; love the message board.

Going by this objectively I have a graph at home that shows the 802 8G freq response to the very similar to the 902 w negligible Off axis spread in the upper freq. when I get home I'll post it.. Actually been a while since I last looked at it. Personally I don't the diaphragms in more recent models have any real difference. The old ones on the other hand is a rabbit hole one should be ready for a long free fall

Personally I like the 802 8G and that could be from my many years of guitar and using alnico pickups. Both are excellent drivers and one isn't really better than the other IMO . It's pretty much pick your poison.

Welcome!
I agree, I don't think you can go wrong either way.
Ron

[bowtie427ss]

.BTW- I personally like the 802G's better with my lite Frams !! But the 902-8A originals sounds fabulous too.They are so close it could be a toss up.But in my experiments (blind) i picked the 802G's.. To each his own !

More isn't always better. In this case it may be that the HF extension of the 902 caused an imbalance in the system to your ear that is more accustomed to the signature of the 802G. I've seen people have this experience in other situations.

They are so close it could be a toss up

Absolutely concur.

It cannot be over emphasized that we're talking about very small differences here..

I also want to emphasize that i do not dislike the 802G or think it is a bad or flawed driver. In the simplest terms it is my opinion that the earlier style 802's with annular steel phase plugs(damped cover, no loading cap) are capable of the smoothest 500hz XO transition(for some listeners the midrange performance at XO is what makes or breaks a loudspeaker), and the 902 has the best HF extension and long term magnetic stability of the small format drivers. While it's still an excellent driver, the 802G's most outstanding characteristic among it's peers seems to be it's market value.

[Altec Best]

While it's still an excellent driver, the 802G's most outstanding characteristic among it's peers seems to be it's market value.

OK, but why do you think it has great market value over say the 902 ?