[bluemonkeyflyer]

  a friend of mine had this sennheiser, so i had the chance to listen to. the sennheiser px100 II is really dark sounding, no highs, so may fit, but i would not use this driver for a mod. if you spend $20 more you could get a sr60i.

Good to know...thank you!

 

[Levictus]

How bout these...

http://www.lunashops.com/goods.php?id=2866

http://www.lunashops.com/goods.php?id=2865

 

[fleasbaby]

Hmmm...they don't give impedance, and why 4 soldering points instead of two? The more expensive ones look more promising, even though they look less like a Grado driver...

 

[wje]

  Check this out:
 
http://www.parts-express.com/pe/showdetl.cfm?partnumber=279-090
 
Too bad it's no longer available. Almost looks like a Grado driver.

 
Oh .... beautiful !!!  I'm going to post a WTB in the Parts Express forum as normally when something like this happens, people might tend to buy up big quantities of this item.  Then, months later, they don't have any use for them and they'll unload them.
 
Now for the really "sad" part about this item at Parts Express.  I used "WayBack Machine" to look for a snapshot of the Web page with additional details.  Back in June, 2013, these drivers sold for an astonishing $1.90 each,  as reflected in the provided graphic.  

 
 

 
 

  Thanks, Wayne! I'm going to order the Koss KSC75 and take look. 
 
Are you aware of any other possible "foster drivers?"

 
Keith, not in my travels yet.  But,  I do keep my search going.
 
 
Edit: Some comments on the drivers from the Parts Express forum.  The driver sounds a bit light on the lower end with respect to bass.  But, there is also a reference in the forum to Mouser electronics where someone indicated that there is a better driver available from Mouser.  I need to check this out, STAT.
 
 
Edit: Mouser has the Kobitone 40mm drivers for $5.14.  None in stock, but over 5,000 on order.  But ... they are 600 Ohm drivers.
 
http://www.mouser.com/ProductDetail/Kobitone/25CE500-RO/?qs=sGAEpiMZZMuTkJYgZlQcSVbB3GhupWizF9xoryPX6%252bQ%3d

 

[jonbmet]

Hmmm...they don't give impedance, and why 4 soldering points instead of two? The more expensive ones look more promising, even though they look less like a Grado driver...

I'm guessing that two of the points go to the voice coils....the other two for the input cable.

WJE....$1.90 is awesome. Makes me wonder if that is what Grado and turbulent labs are paying? Possibly less since I'm sure they buy in large quantities.

 

[wolfetan44]

Hey, Wje if you order those 40mm drivers from Mouser, would you mind telling me how they are? Thanks!

 

[wje]

  Hey, Wje if you order those 40mm drivers from Mouser, would you mind telling me how they are? Thanks!

 
Will do.  I read into the specs a bit and it looks like they go down to 90 Hz and up to 20 kHz.  But, I'm honestly on the fence about the drivers as they are 600 Ohm drivers.  I do still have my Audio-GD amp though to give them some juice.  The price, though, is a no-brainer for a tweaker.  It looks like they have a 14-week lead time.  But they are expected to ship on 11/27/2013.  My guess is that Mouser will have them on the shelves in the 2nd week of December.

 

[wje]

  Hmmm...they don't give impedance, and why 4 soldering points instead of two? The more expensive ones look more promising, even though they look less like a Grado driver...

 
4 Soldering points.  When you FUBAR two of them, you still have two good solder points as backups.  

 

[wolfetan44]

 

  Hey, Wje if you order those 40mm drivers from Mouser, would you mind telling me how they are? Thanks!

 
Will do.  I read into the specs a bit and it looks like they go down to 90 Hz and up to 20 kHz.  But, I'm honestly on the fence about the drivers as they are 600 Ohm drivers.  I do still have my Audio-GD amp though to give them some juice.  The price, though, is a no-brainer for a tweaker.

Are those good specs or no? Sorry, I know next to nothing about the technical side of audio.. 

 

[wje]

  Are those good specs or no? Sorry, I know next to nothing about the technical side of audio.. 

 
I wish the lower end extended a bit below 90Hz.
 
On another note: Sony MDR-MA300 Over-Ear Stereo Headphones Deep Bass 40MM Driver Black.  These beasts sell for $39.99. Keep the 40mm drivers and dump the rest.  

 

[wolfetan44]

 

  Are those good specs or no? Sorry, I know next to nothing about the technical side of audio.. 

 
I wish the lower end extended a bit below 90Hz.
 
On another note: Sony MDR-MA300 Over-Ear Stereo Headphones Deep Bass 40MM Driver Black.  These beasts sell for $39.99. Keep the 40mm drivers and dump the rest.  

Haha

 

[Levictus]

Here is a Link with specs and availability from China, I didn't realize the one I posted before was sold out... Group buy?

http://www.eforchina.com/view/3657/40mm-Repair-Parts-Speaker-Unit-for-Headset--Pair-.htm

 

[Levictus]

Here is the mouser with all the Kobitone drivers, looks like there are some 8ohm models

http://www.mouser.com/catalog/catalogusd/646/2029.pdf

 

[wje]

  Thanks, Wayne! I'm going to order the Koss KSC75 and take look. 
 
Are you aware of any other possible "foster drivers?"

 
I have the KSC-75 drivers in woodies right now.  I have Roberta Gambarini playing some sweet jazz for my ears.  
 
Some brief impressions (not scientific):
 

1. Low end - not pulsing.  But, when I hear the upright bass playing, the string plucks are quite evident from a sonic sense.
2. Mids - not really lacking in that regard.  Still need to push some other genres and artists through this setup, though.
3. Highs - Cymbals from the drummer present themselves accurately.  Detailed.  Not really over the top or too excessive -- then again, I'm familiar with the Grado house sound.  Others who don't the Grado sound, might not really love these drivers.  Highs are detailed, yet not piercing.
4. Overall - Performing better than I had ever anticipated.  With the details of the percussion, upright bass, etc., as well as vocal quality, these drivers when one considers the cost are a winner.  I'm not sure which Grado model I'd start to compare this driver too, though.  With the level of detail, maybe, the SR-325.  Then again, I haven't heard the SR-325 in a few years, but was familiar with the sound at one time.   Female vocals to give a presence of sibilance. ***  The sibilance is a bit better controlled with the Grado driver.  However, the sibilance of the KSC75 isn't to the point of being a deal breaker like the HifiMan HE-400 was.
5. Pads utilized: Sennheiser HD-414 pads with the "true" reverse quarter mod and not the mis-understood modification like I see 75% of the people apply.  Also, I used the TTVJ "flats" and the details in the bass were ever present again.
6. Cable, cups, etc. utilized: Wooden Padauk cups.  Standard 4-conductor Grado cable crudely soldered to the leads on the Koss drivers.  Electrical tape was quickly placed on connections to prevent any "shorts" from occurring.
7. Notable items:  I've read some comparisons between the KSC35 and KSC75.  The KSC35 was made several years ago, but some people have reflected that the KSC35 is a bit less sibilant than the KSC75.  Also, other comments indicated that taking the drivers from the Koss Porta-Pro headphones was recommended as the drivers would fit into the casing for the KSC75.  The bass is a bit better in this case.  I don't have the Porta-Pros, but do see they are about $38.00 on Amazon.  Also, about $42.00 on Ebay with free shipping.

 

1. Late breaking comments:  During the write-up summary, I toggled through some different genres.
2.     Jeff Golub in "My Three Kinds" - this a blues album covering the work of the (3) Kings who were all bluesmen with the same last name of King.  The guitars, vocals and lower end is really quite good.
3.     Boney James - Sax and drums on "The Beat" were nicely presented.  The vocals were good too.
4.     Yellowjackets - Great detail in their piano, percussion and saxaphone instruments.  The don't use vocals, so this can't be evaluated with their music.
5.     Bettye Lavette "Thankful and Thoughtful" - Good low-end tracks on this album.  Her vocals are detailed, yet not sibilant.
6.     Melody Gardot "My One and Only Thrill" - Great vocals - brings out the variation and detail of what she really is capable of with her singing.  
7.     Arturo Sandoval "Journey to Chateau de le Feun" -- Great sound and presence with his trumpet.  Keyboards were enjoyable to hear.  This album is detailed ... yet has punchy tracks on it.
8.     John Ginty "Bad News Travels" - John is a Hammond B3 organ king.  This whole album has his B3 whaling away through the tracks.  The man is talented at making this organ run "full throttle" to put lots of intensity into his songs.  The Hammond played                  pleasantly through the Koss drivers.               
9.     Norah Jones "Fees Like Home" - Good.  But, the presence of Norah on these drivers seemed to be trying a bit too hard.  She and her voice wasn't as set back as I remember the songs to be on other speakers and headphones.
10.     Johnny Cash American IV "The Man Comes Around" - Good acoustic guitar and piano.  Johnny's voice came across a bit odd.  Not as "true" as I know for these songs to be on other headphones.  
11.     Johnny Cash "Ain't No Grave" - After trying to decipher Johnny's voice on the previous album, I decided to give this a listen.  Better, yet still not the true Johnny that I recall from other Grado experiences that I've had.  Not sure about this.
12.     10,000 Maniacs.  Natalie Merchant has a very lovely voice.  She sounds "on cue" with the Koss drivers.  

 
*** - I should note that the sibilance on the Roberta Gambarini album that I have is noted to be sibilant.  I've experienced this on other headphones, too.  I don't want to indicate that this is a weakness on the KSC75, when it really is not.
 
### -- I'm getting a bit drowsy.  I think some of my impressions should be taken with a bit of a grain of salt.  My listening isn't as tuned in towards some of the details in the artists and their music to share further detailed impressions.  Again though, I'll give more comments when I'm more awake and have had more listening time.  Also, for those who spring for the $9.99 to play with this driver, I will also be interested in the dialog that could take place.  The KSC75 isn't an RS1i killer by no stretch of the imagination.  Though, I think it is worthy of comparing against the Grado SR-60, 80, 125 and 225 to see how it stacks up against those models.  Time to hit the "Submit" button as I've had this reply open for the past 50 minutes as I was listening and collecting some impressions to share.

Here is a Link with specs and availability from China, I didn't realize the one I posted before was sold out... Group buy?

http://www.eforchina.com/view/3657/40mm-Repair-Parts-Speaker-Unit-for-Headset--Pair-.htm

 
From the pictures, the first thing I noticed on the back magnet of the driver were the two vent holes.  Placed similar to how Grado has theirs on the backs of the drivers.  I'll have to look at other drivers of this nature to discover other likenesses that might be present.  

 

[wolfetan44]

Anybody happen to know what size the Fostex T50RP driver is?