[Andykong]

I wish I could find a place seeling the ESP-950 at $600, have been hunting since Christmas with no luck so far.

Finally collected the ESP950 from a Head-Fier during my LA trip, good condition and good price, really happy about that.

The headphone is newly repaired by Koss (a minor squeal), the repair notes stated that the following items has been replaced:
Cushions
Elements
Cover foam
ADh Ring's
Carton

So what exactly are the items? is there a diagram illustrate the ESP950 components with "proper" names?

Can I assume the Elements are equivalent to the diaphragm/membrance of the ear piece?

Cover foam is something like this?


And what exactly are the ADh Rings and Carton?

 

[Mr.Sneis]

I wanted to share some of my recent personal experiences with the venerable ESP-950 powered off some Stax built amps and the modern Stax Lambda SR-407. Hopefully it is of value to someone looking for something other than the latest, greatest, or most expensive gear around! 
 
To begin I consider the ESP950's on the neutral and somewhat aggressive side but just smooth enough to be non-fatiguing, the Koss are also less open or expansive sounding than the best available but at least better than the Senn hd6x0 series.  The bass is a weakness to my ears with only a little kick but still the ability to play low regardless.  I also describe the e/90 as not a bad amp but it tends to smooth over or smear some of the details that the Koss is most definitely capable of and just like the phones themselves, the amp has a really uninspiring tactile build quality.
 
I use a one of a kind, warm sounding, source with the associated equipment: a once TOTL Adcom GCD-750 cd player with an upgraded uber analog stage. For media I use both CD's and FLAC files of various mastering quality pushed through its old 20 bits PCM1702 DAC fed from a bottom of the line m2tech Hiface 1.
 
ESP-950 + Stax amps:
 
I picked up a srm-007tii (Raytheon tubes) because I was hoping the hybrid tube amp would mate well with the Koss to produce some flavor and add some robustness to the sound, after some listening I felt like the combo was a bit lacking - the Koss became flatter than usual so it was more or less just too boring for me and I quickly dismissed the affair.  The 007tii however paired very well with the SR-407's which helps to hide the brighter (I never found it horrible) nature of the Stax.  My guess is that maybe the amp just didn't push enough voltage/current/juice to bring the Koss to life; maybe they needed an amp with a bit more finesse than I was lead to believe.
 
I also went through a 252s and now a 323s.  The 252s did very well, definitely helped to give the Koss a light kick in the pants while not changing the overall tonality.  The 323s kicked harder and sounded bigger or arier with a very clean clear and under control presentation.  Though not the injection of flavor I was shooting, it seemed the esp950 really liked the two solid state amps and that neither could change the tonality of the Koss but rather improve upon what was there to begin with.  If there was a winner in the context of this posting I guess I would call it the esp950 + 323s but I know deep down there's better more expensive free trade amps out there.
 
My biggest gripe with the 323s is the build quality; it's like comparing a modern 18lb stereo receiver versus a 45lb vintage receiver.  Most full sized Stax amps tend to be be built like tanks weighing a lot and can be made into portable heat generators while the 323s feels like Stax put a 252s circuit board in a new lightweight enclosure with two jacks and in-built a power supply as a cost reduction move.  My cell phone burner probably packs more heat than the 323s.  This is of course is a cosmetic thing but I happen to subscribe to the bigger is better mentality and I'm not sure why it isn't brought up more often.
 
SR-407:
 
The 407 has better fit and finish than the esp950, you will find greater heft and clamping force but similar construction using the finest of plastics and a superior fake leather.  The 407 does not sound at all similar to the esp950, it has wider left to right sound staging and more fun and engaging of a listen.  I don't recommend listening to both back to back for musical enjoyment as that's when the differences become an issue.  I found myself unable to go back to the Koss after extended sessions with the 407 unless I had some adjustment time in between. Out of the amps above I determined the 252s is a bad fit for the 407 becoming lifeless and dull while the 323s was much improved albiet introducing a hint of brightness when I went looking for it. The 007tii was a compromise and had more sparkle and bass weight but rolled off the highs and smeared some of the details.  The 007tii made the 407's sound maybe like sitting in a dirty smoke filled jazz club while with the 323s your are in the recording studio behind the glass yelling at the band to do more drugs.  I could live with the 407 + 007tii or even the 323s but this stupid hobby has me chasing (read: throwing away more money at) some of the older Stax lambdas already.
 
They say the Stax x07's further an agenda of the modern Stax sound; that is the brightness faux pas which can make the listener think that what they are hearing is great detail but is truly masked by artificial and fatiguing exaggerations.  While I would agree with this to a certain degree I wouldn't call it a deal killer like some make it out to be. While the 323s made brightness more apparent in the 407's, at least it was nowhere near the level of a Grado, the Sony V6, or the 6k treble peak of the HD800.

 

[s1rrah]

Just an FYI ... but there's a site currently selling ESP-950 to Stax adapters ... they are a bit over the top expensive but for folks like myself, who wouldn't want to DIY or source the parts myself, ... the $150 asking price wouldn't be so bad.
 
I've already got one, though so just mentioning for those who might be wanting one for their own 950's ...
 
https://fongaudio.com/store/default/headphones-16/headphones/koss-esp-950-to-stax-5-pin-adapter-cable.html
 
....
 

 

[ambchang]

That's ridiculous.
 
The extension cable is about $15, the stax plug another $20, it's a very simple soldering job.  I just can't justify that $150 price tag.  Realistically, it's $50 max.

 

[Andykong]

Sorry to ask this again, can someone enlighten me on what exactly have been replaced by Koss in recent repair? I have attached the repair notes for reference.

 

[Mr.Sneis]

Sounds pretty extensive... Is it a new set or the same set with replaced parts?

 

[Andykong]

Sounds pretty extensive... Is it a new set or the same set with replaced parts?

I bought this from a member of Headfi two weeks ago, that was a very smooth deal and I am consider myself lucky to get a good deal in a tight schedule. The unit is around 6 months old, one of the $600 discount deal in last Cyber Monday.

The unit has minor squeal, so the seller sent in to Koss for checkup before selling it to me. I got the unit immediately after Koss done the repair and this is the note I find from the repair. I am surprised that Koss replaced the elements, unfortunately the note didn't listed the problem diagnosed, just a list of parts replaced, so I have no idea if there is any problem other then the squeal issue.

So what exactly is the Ring and Carton in the second line of the replace list? Can someone please help to explain?

 

[n3rdling]

I think "adh" might stand for adhesive?

 

[Kokomo O]

And carton for the box it came in. Ring is anybody's guess. Sorry.

 

[Buddhahacker]

  Just an FYI ... but there's a site currently selling ESP-950 to Stax adapters ... they are a bit over the top expensive but for folks like myself, who wouldn't want to DIY or source the parts myself, ... the $150 asking price wouldn't be so bad.
 
I've already got one, though so just mentioning for those who might be wanting one for their own 950's ...
 
https://fongaudio.com/store/default/headphones-16/headphones/koss-esp-950-to-stax-5-pin-adapter-cable.html
 
....
 

Thanks s1rrah for the link. I hung up my solder gun, solder sucker and flux along time ago. 

 

[Buddhahacker]

Any recommendations on a good amp for the ESP-950?

 

[s1rrah]

  Any recommendations on a good amp for the ESP-950?

 
The affordable option is a Stax SRM-252S. It's tiny but costs around 400 bucks. I had one for a while and it's very nice with the 950's. Currently using a SRM-323S which is also very good with the 950's. I think the 252S sounded just about as good as the 323S but wanted the extra power/headroom of the 323S in case I get into some of the more hard to drive Stax cans.
 
Both 252S and 323S have more drive and body to the sound than the ESP-950 amp ...

 

[Buddhahacker]

Great! Thanks for the guidance. Much appreciated.

 

[fzman]

Anyone compared these with the new King sound offerings? They seem promising as well.

 

[spritzer]

The Koss is far superior, both the phones and the amp.  No comparison really...