902-8B or 902-8T

[eeehaah]

Does the T mean the Tangerine phase plug?

Which driver would work best for home hi-fi with my Altec 415C Bi-Flex high passed at `7000 Hz?

Are these 902's better than JBL 075 for my purposes?

Thanks,

eeehaah

[AllanCT]

I prefer the 077 myself.

Assuming a good electronic crossover and gain matching with some mechanical alignment I'd probably go with the JBL 075 if you already have them.

But I'd get the Altecs for the midrange and cross them over in the 500-800 range even with the Biflex. Or at least experiment with them.

You can never have too many Altec speakers.

[eeehaah]

Thanks, I just bought one 077 and pair of 075 on eBay, ran out of money now for the 902 pair LOL. I'm just mono biflex at this point anyway. I'll compare the 075 and 077 on my biflex and re-list the less favorite(s).

Do you know if 902-8 or 902-16 show up on eBay often?

Thanks for your advice,

eeehaah

[David Deratany]

They show up all the time. I just got a pair w/o diaphragms for $81. The day before, a pair went for $153, also w/o diaphragms, so it might be best to be patient.

I think it wiser to get a pair without diaphragms and then get new ones from GPA; that way you'll know you've got the best and not have to wonder, or maybe have to replace them.

[AllanCT]

I do know the 075's can be crossed over a lot lower than the 077's.

They can play down to 2.5K or so on a 2 way application.

I used a pair in a car stereo application years back. Worked great much more compact than the Altec horns I was using previously LOL.

The 077 slots are purposely built for supertweeter 6.5K and up crossover points and extremely wide dispersion and ultra high frequency response along with good sensitivity and high output.

Tune to your ears, it's all that really matters.

[eeehaah]

So what's different about the 902-8T?

Thanks for the help,

eeehaah

[Todd W. White]

The only difference between the standard 902-8A/B and the 902-8T is the "T" and what it represents:

902 = driver model number
- 8 = impedance
A or B = latest model in the series

T = THEATRE use.

The "T"'s were used in the theatres. They had a rear loading cap on the back of the 902 diaphragm because they had to handle the higher power of the newer amps once Thomlinson Holman, Luke Skywalker, and Steven Spendberg got into the movie business. The old 808's had these, too.

From a performance standpoint, the "T" was a cross between a real 902 and a 908. Remember - this was BEFORE the days of Jerry Hubbard's Pascalite.

For normal applications, the 902 is fine. Take your "T"'s rear cover off, remove the screws that hold the loading cap in place, then go down to the hardware store and get new, stainless steel machine screws of the same thread, but pick up ones that are short enough to hold the diaphragm mounting ring down firmly to the top plate. You can ascertain this length by screwing one of the old screws back in (sans loading cap), screw it down all the way, and making a note of how much of the screw is still protruding above the mounting ring.

Once you've replaced the screws, glue a heavy piece of felt into the back of the rear cover, reassmble, and - WELLA! You now have a 902-8A/B!

<font color="#FFFFFF" size="1">[ February 03, 2003 11:12 AM: Message edited by: Todd W. White ]</font>

[stpower]

Todd,
I just bought a pair of 902-8b's on E-Bay last month. I took the rear covers off and they have the loading caps! Were there any 902-8b's built with the caps or did somebody possibly switch rear covers with some T's? No big deal, I can easily convert them with the screws and felt as you mentioned.
Regards,
stpower

[Steve Burger]

Hi this is Jim D, I'm over at Steve's and his computer is faster than mine. The 902-A has no loading cap and no centering ring below the voice coil which effectively allows the diaphragm to vent into the magnet cavity. The T is an A with a loading cap to prevent the diaphragm from moving too far at higher power input. The B has the centering ring which prevents venting into the magnet and a loading cap. All As amd most Bs have a 7/8 exit. About 1989, Jerry Hubbard then cheif engineer of acoustics at Altec, changed the 902s and 908s and the new 909 to a 1" exit. To complicate matters further the last production of 902Bs, 908Bs and 909As once agin were built without the centering ring. Yes they sound better without the loading cap and centering ring, although they may handle slightly less power. Jim

[cclark65]

I have 2 sets of the Altec 902-8b, and they both have the loading caps on the back, as well as the 902-8t's that I have. The one set of 902-8a's that I have do not have the loading cap.
I use them for live sound, so I prefer to have the loading cap in place. I keep the 902-8a's for home use only, they do sound a little better.