Spongeworthy Posted November 25, 2007 Share Posted November 25, 2007 What is the difference between an Altec 902-8B versus a 902-8T? Thanks. Quote Link to comment Share on other sites More sharing options...
Professor Thump Posted November 25, 2007 Share Posted November 25, 2007 What is the difference between an Altec 902-8B versus a 902-8T? Thanks. I thought that the T version was with a 70 V distribution transformer. I will see if I have the data sheet at work. According to this link the driver is a 500 Hz cutoff design with a filter cap. http://www.altecpro.com/pdfs/vintage/SpeakerAndMics/drivers/902-8A%20902-16A%20902-8T%20HF%20Drivers.pdf Quote Link to comment Share on other sites More sharing options...
mungkiman Posted November 25, 2007 Share Posted November 25, 2007 This is a guess on my part. Beryllium VS. Titanium diaphragm? Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 25, 2007 Share Posted November 25, 2007 People weren't making berylium diaphragms when Altec stopped making those. The 'T' as a lighter weight aluminum diaphragm, and gives a higher end freq. response. They were replaced by the 'B' diaphragms, and those drivers also had a loading cap on the back, and could handle increased power. At least that is what I have read elsewhere. I think Great Plains Audio has some info on this topic posted somewhere on their website. Quote Link to comment Share on other sites More sharing options...
djk Posted November 26, 2007 Share Posted November 26, 2007 "design with a filter cap." It's a mechanical loading cap to reduce the rear chamber volume. "People weren't making berylium diaphragms when Altec stopped making those. " Yamaha was making Be direct radiator domes in the mid 70s, Pioneer hired some ex-JBL engineers and made Be compression drivers in the late 70s (TAD). JBL has recently started making Be compression drivers. Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted November 26, 2007 Share Posted November 26, 2007 People weren't making berylium diaphragms when Altec stopped making those. The 'T' as a lighter weight aluminum diaphragm, and gives a higher end freq. response. They were replaced by the 'B' diaphragms, and those drivers also had a loading cap on the back, and could handle increased power. At least that is what I have read elsewhere. I think Great Plains Audio has some info on this topic posted somewhere on their website. Bruce, So what is the "A" as in 8-A or 16-A? Thanks, tc Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 26, 2007 Share Posted November 26, 2007 tc, Since I was wrong about the beryllium, etc. (you know dennis always sets me straight), perhaps he can give a definitive answer. I'm not digging at dennis, I just don't know the answer. [:|] Bruce Quote Link to comment Share on other sites More sharing options...
fini Posted November 26, 2007 Share Posted November 26, 2007 Yeah that guy knows everything! OTOH, for all I know, he might be making up half of it... ;^) Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 26, 2007 Share Posted November 26, 2007 Yeah that guy knows everything! OTOH, for all I know, he might be making up half of it... ;^) Sssshhhhhhhhhh!!!! Careful fini... you could end up on the list....[:#] Quote Link to comment Share on other sites More sharing options...
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