[takato14]

 
Sony DR-Z6 (left) and Sony DR-Z7 (right). Huge 53mm dimpled-surface dome with a palladium (!!!) coating. Absolutely stunning.

 

[GREQ]

 
LEFT - AKG K141 Monitor (Gold)
RIGHT - the usual dead K241 (for comparison)
 
Interesting notes about K141 driver:
- 1 dot on middle of driver
- Same outer vent scheme as K240 Monitor (1st post in entire thread)
- stronger outer ribs just like the vintage K141 driver (silver)
- 6 Big holes/vents in the middle of the magnet chamber (unlike any other 'vintage' akg driver i've seen so far)
 
I know some of you will cringe at this, but if I brush my finger gently across the diaphragms, the K141 produces a much higher frequency than the K241.

 

[takato14]

 
 
LEFT - AKG K141 Monitor (Gold)
RIGHT - the usual dead K241 (for comparison)
 
Interesting notes about K141 driver:
- 1 dot on middle of driver
- Same outer vent scheme as K240 Monitor (1st post in entire thread)
- stronger outer ribs just like the vintage K141 driver (silver)
- 6 Big holes/vents in the middle of the magnet chamber (unlike any other 'vintage' akg driver i've seen so far)
 
I know some of you will cringe at this, but if I brush my finger gently across the diaphragms, the K141 produces a much higher frequency than the K241.

Why would we? Most dynamic drivers are very durable unless they're deficiently designed.

 

[GREQ]

 
Why would we? Most dynamic drivers are very durable unless they're deficiently designed.

Because "some" people are not "all" people and "some" people don't like to tempt the ultimate fate of a piece of precision equipment where even the slightest changes in tolerances can affect performance. 
Of course, I'm not one of them unless I paid a lot of money for something. 

 

[GREQ]

Dero D-550 driver rear - 50mm diameter - transparent plastic diaphragm (can't take photo as it's glued to the baffle)
 

 
 
Sony DR-Z7 
 
  
 
Notice on the 3rd photo that two different materials are used on the vents. 
The fabric on the right is very thick, and light does not penetrate it. Two vent holes have tiny needle punctures in the fabric.
The fabric on the left is semi-permeable, allows some light to penetrate.
Seems like someone at Sony spent quite some time thinking about the tuning of this driver. 
Personally I would love to tear all that material off and tune it myself, but the thick red glue holding it down is near indestructible. 
 
Does anyone have a good guess as to what the rear magnet housing material is made of? It's seriously industrial and as heavy as it looks.

 

[kramer5150]

one of the all time coolest HF threads... I never knew the Koss TD-80 has 55mm drivers.  Bigger doesn't always translate to better though.  I see those things all the time on ebay... usually very cheap.

 

[MDR30]

 
Sony MDR-F1, cut out of its housing.

 

[takato14]

  Sony DR-Z7 
 
Does anyone have a good guess as to what the rear magnet housing material is made of? It's seriously industrial and as heavy as it looks.

That's actually the entire magnet. It's a very strongly magnetized proprietary alloy. Additionally, the frame of the driver is SBMC (Sony Bulk Mould Compound), a very dense non-resonant material used in their high-end turntables and such. 
 
I do not advise messing with the driver tuning. I tried several different things with the Z5 and all I managed to do was create a nebulous cloud of bass fart. 

 

[takato14]

 
 
Sony MDR-F1, cut out of its housing.

Size? 
 
Also rather interesting, that film looks pretty thin. Maybe that's why my friend's NOS F1 died within a week...

 

[khbaur330162]

  Size? 
 
Also rather interesting, that film looks pretty thin. Maybe that's why my friend's NOS F1 died within a week...

The example posted by MDR30 has had its bass lens and baffle coupling removed, too, just fyi (looks like a pretty clean job, imo). Anyway, I guess this is an MA900 driver, but the F1 looks very, very similar, if not identical.

 
The diaphragm is rather thin and fragile, iirc, but my guess is that's not why it failed. I suspect misuse either by your friend or the original owner, or both. The F1's are rather sensitive, perhaps a user cranked the volume while trying to use them as desktop speakers, or simply listen to their music from another room. Then again, perhaps the faulty F1 drivers in question were one in the same with the photographed driver sans bass lens, in which case I'm guessing I was actually the one who broke one of the lead in wires and reconnected it with conductive epoxy. If that's the case those drivers went through quite a bit, there's a story behind them. Anyway, I believe I gave those away as a bundled gift during a headphone trade/swap, or just as a gift along with some headphone damping materials and such, I don't quite remember. If they are my drivers I hope they didn't cause too much headache for anyone, I know what that's like. Hopefully it was at least a good learning experience? I'd at least like to know how they sounded in a sealed enclosure for the week that they did work! xD Never got around to that one myself.

 

[takato14]

  I suspect misuse either by your friend or the original owner, or both.

But it was unopened, brand new, it couldn't have been done by the original owner. 
 
And absolutely not misuse; he's meticulously careful with every single one of his possessions. Every single headphone of his I've sold looked brand new, despite several years of ownership. They just started buzzing and distorting out of one side shortly after he got them; it wasn't even a week iirc.

 

[kman1211]

Sennheiser HD 545

 

[MDR30]

  Size? 
 
Also rather interesting, that film looks pretty thin. Maybe that's why my friend's NOS F1 died within a week...

 
Housing diameter: 51,4 mm
 
Effective diaphragm diameter: 46 mm
 
It's thin, but in my opinion the problem with this driver was the low impedance (about 22 ohms without circuit corrections, nominal impedance 12 ohms) which probably made it slow and heavy, and not able to reproduce the high harmonics of violins etc.
 
I cut the drivers out to make place for substitutes in the MDR-F1. Another unusual thing about this driver is the slight cone shape of the centre dome.
 

 

[GREQ]

DERO MODELL D-500
http://www.head-fi.org/t/420490/show-us-your-vintage-headphones/1110#post_10512530
 
 

 

[GoldenboyXD]

Is there a guide on how to remove the AKG 701/702 drivers? Was it just some screws and pullout as is or was there any obstacles like locking mechanism inside the cup.