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View Full Version : Genuine 2410 Diaphragms?


Mike F
03-08-2015, 08:43 PM
Hi All,
Seeking authentication. Foilcals say 16 ohms but they measure in at around 6.2.
Do they seem legit to you?
TIA!
martin2395
03-08-2015, 11:50 PM
6.2 DCR is correct as DCR is what you measured, not the driver impedance ;)

Not so sure about the diaphragms, I always thought that the underside of the assembly should have a gold color.
subwoof
03-09-2015, 06:57 AM
gold is the later color - back then all the "rings" were natural aluminum.

They look correct but the picture(s) are very poor..

sub
grumpy
03-09-2015, 07:03 AM
Would these (2410 diaphragms) have the distinctive small dent?

I seem to recall a post and pictures regarding a small distinguishing
defect in the forms... pictures here are too fuzzy to see that level
of detail.
JeffW
03-09-2015, 08:35 AM
Would these (2410 diaphragms) have the distinctive small dent?

I seem to recall a post and pictures regarding a small distinguishing
defect in the forms... pictures here are too fuzzy to see that level
of detail.

Yeah Steve Schell posted pics of the little bump that was in the original die, he had an early - maybe the original - diaphragm and mentioned all subsequent diaphragms copied the bump. It was on the edge of one of the surround ridges near the outer edge IIRC.
Mike F
03-09-2015, 03:12 PM
I apologize for the crappy pics, here is a better one. Judging by a quick RTA sample, I would have to say that they are the real deal.
They track each other well and respond to beyond 15khz.
JeffW
03-09-2015, 04:12 PM
Found it, seems as though the bump was on 175 'phragms until the mid 50s or so - probably a little early for this pair.

http://www.audioheritage.org/vbulletin/showthread.php?29273-Interchangability-of-1-75-quot-diaphragms-Altec-JBL&p=293934&viewfull=1#post293934

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=47198&stc=1&d=1282595236