The Headphone Driver Pics Thread
Oct 5, 2012 at 7:18 AM Post #256 of 2,345
Just a few cheap dynamic drivers on show here.

 
From left to right:
Sony DR-7 -- Universum 349540 5 -- Philips SBC 3150 -- AKG K241 (for size comparison)
 
Sony - surprisingly better than A LOT of modern cheap headphones - very warm sound.
Universum - these are hilariously thick and heavy. The diaphragm is quite thick. Sounds horrible.
Philips - needs very careful tuning, but nothing special. 
 
Nov 2, 2012 at 9:54 AM Post #257 of 2,345
Something a lot more juicy than my previous post - Rank Arena SK-600 drivers.
I believe they are dynamic drivers with an aluminium membrane/diaphragm. (outer diameter 75mm, inner diameter 60mm)



 
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Nov 2, 2012 at 10:53 AM Post #258 of 2,345
Sennheiser Unipolar 2000. Entire diameter ~104 mm, driver surface diameter ~90 mm. The front looks the same but without the disc in the middle.

 
Closeup of ear gunk on the protective plastic wrapping.

 
Dec 4, 2012 at 9:30 PM Post #260 of 2,345
not often seen, if at all, P.W.B. Moving Coil M.C.3. ( Peter W. Belt )

 

 
Unknown specs, date possibly very late '70's
This is from the Grey model, I have seen, but do not own,  a P.W.B. Black Moving Coil model also. Unsure which one is the exact one listed in the catalog sheet dated 1978 ( scan for that PWB stuff seen in the Ortho Roundup thread )
 
Ring magnet. Surrounded by foam, also the center dark spot is foam
Mylar dynamic diaphragm .
 Black driver housing measures ~56mm outside edge to outside edge. Big driver cannot see the edges looking through holes in front.
very thick wiring in the cables.
OOOPS  I should have tested the driver impedance when i was resoldering them. Someday.
 
 
anyone seen a vintage driver of this design that might help narrow it down?
 
Dec 5, 2012 at 6:09 AM Post #261 of 2,345
Quote:
not often seen, if at all, P.W.B. Moving Coil M.C.3. ( Peter W. Belt )

 

 
anyone seen a vintage driver of this design that might help narrow it down?

 
Those look VERY similar, if not the same as the two big drivers in the middle of my photo below: (3rd from the right)
Printed on the back is : "Japan DR0070 400[size=12.800000190734863px]Ω"[/size]
Quote:
Just a few cheap dynamic drivers on show here.

 

 
Dec 5, 2012 at 8:10 PM Post #262 of 2,345
wow reallly close.
 even the large solder tabs there with the orangey-brown below them.
You mention cheap, do you recall what they came from? Oh I see Universum. That German brand.
 Just wondering because this guy ( P.W.B.) usually dealt with stax/Audio technica stats drivers, and being very eccentric I don't think he did anything halfways or approaching cheapo, these might be the exception though.
 
These have a vintage slant to them but not entirely hideous sounding
 
Thanks for this, what are the odds they would be randomly posted a couple of posts earlier in here, if they are indeed exactly the same. I'll have to look at the front side
 
Feb 21, 2013 at 8:22 PM Post #265 of 2,345
Pioneer SE-90D, continued.
 

 
The metal driver guard (left) cannot be removed without breaking the driver (yep). The four slots surrounding the center of the metal guard are covered by a small metal ring (top) that had been glued onto the driver guard seemingly as an afterthought. The measurements I did say that removing the metal ring decreases the treble around 10 kHz by several dB.
 
Mar 6, 2013 at 1:53 PM Post #266 of 2,345
Sennheiser Momentum. 
Sorry it's not photos of the bare driver. I would like to keep my warranty intact. 

 
 

 

 
Mar 8, 2013 at 11:04 PM Post #267 of 2,345
Probably been posted, but here's a bunch of KOSS Pro/4AAA drivers. There are 3 different series of drivers, and are in EP, MP, and LP production models respectively.
 
Series 1:
 

 

 

 

 
Original KOSS Pro driver from the mid 70's. Very intriguing design with a large voice coil and a fairly thick diaphragm that isn't glued down, but instead held in place by a metal ring. The plastic housing follows the shape of the diaphragm, leaving a small gap of air between the two parts. Has a very large, heavy magnet. Great soundstage, incredible bass, lush mids. Somewhat recessed treble. Very detailed. A very powerful sound with no peaks or resonances. Original paper damping deteriorated and was replaced with fleece. 
 
Series 2:
 

 

 
Redesigned version of the series 1, in production somewhere between 1978 and 1979. Rarest of the three. Has three bass ports instead of four, and foam damping instead of paper. Diaphragm has the same shape but is very slightly thinner. Thinner plastic housing, but a larger magnet. Sound is the best of the three, same sound signature as the original 4AAA but with <MUCH> lower distortion and considerably better treble extension. Has better transient response due to the better magnet and lighter diaphragm, and soundstage is larger as well. Literally a straight up improvement. 
 
Series 3:
 

 

 
Newer driver from the 80's, completely redesigned. Much plainer in appearance. Smaller voice coil and thinner diaphragm. Smaller, lighter magnet. Bigger soundstage but worse everything else. Peaks everywhere. Has the horrible tin can veiling so common in headphones from the 80's. No detail. This driver was used in all "Plus" models of KOSS headphones, and was in production until some time during the 90's. This is the driver that killed KOSS's reputation as a headphone manufacturer. Funny how they put it in the best headphone they ever made until the ESP-950.
 
Mar 9, 2013 at 2:04 AM Post #268 of 2,345
Most interesting and enlightening. First version makes me think of the Pioneer Monitor 10 diaphragm which also wasn't glued/fixed but attached with some foam.

Development doesn't always proceed in a straight line...
 

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