A seller on ebay makes the following statement about the 802Ds that he is selling:
" These are early 802D type with aluminum voice coils same as 802B. Later 802D had copper voice coils."
I'm far from an Altec expert and am learning new things all the time, but I haven't been able to locate a shred of evidence to correlate this claim.
What's the scoop?
GeeDeeEmm
Sounds like he's referring to a 20275 diaphragm.
That's the early style, edge wound aluminum voice coil, 16 ohm diaphragm used in 604B,C,D, & E, 605A, 615A, B, 802B, C, and early D's.
The lit doesn't specify which have aluminum coils, i just know the 20275 does from experience. It's debatable how many healthy examples still exist. No doubt there are some, but they really need to be swept to determine that.
http://www.vintagewindings.com/gen%2...a-VocCoils.pdf
Not all vegetables make good leaders.
I'm not an expert on Altec voice coils.
But be aware that copper coated aluminum wire is often used in HF coils. Easily mistaken for copper.
CCA10%
Also that lit only says some coils are copper and some are aluminum. Not that some HF coils are copper. My experience is generally woofers are copper and HF drivers are aluminum. There is a very substantial mass difference. Aluminum wire is one third the mass of copper wire. A copper coil would seriously degrade the HF response.
Your neighbors called. They like your music.
Agree with Old Guy on all points.
I don't think the 20275 aluminum ribbon was coated. It's the only one i've ever had to dig out of an Altec gap so i've seen it up close.
Here is the attraction to the 20275, it's visually obvious:
Later HF small format coils look like they're coated although there's no mention of it in any of the slick sheets, they simply say edge wound aluminum ribbon. They sure look copper colored. But, that could be the adhesive or insulating coating i suppose.
A couple interesting notes from browsing the A&E specs on a couple sales slicks,
416-8B edge wound copper ribbon
416-8C edge wound copper ribbon
515G edge wound aluminum ribbon
421-8LF edge wound copper ribbon
515B edge wound copper ribbon
421A edge wound aluminum ribbon
Not all vegetables make good leaders.
The only coating I know of is the tinted shellac used to seal such electrical coil windings whether a driver VC or inductor, etc., with the really thick, nasty yellow/brown tinted being for [sub] tropical, shipboard or similar environments.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
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