[Sonido]

  Where did you buy the upgrade PSU?  Please share link if possible.

 
Here:
 
Quote:

   
congrats.
 
I expect to get mine back from Koss this next week some time (had a horrid distortion in the left channel for some reason).
 
In the mean time, not having a gazillion bucks laying about and not wanting to use the Koss energizer, I bought a new Stax SRM-252 for use with the Koss cans and a set of SR-307's I also have.
 
I initially wanted to get a SRM-323S but it's just too big to co exist with my other desktop gear. The 252 will sit/stack nicely and I can use it's parallel outputs to in turn patch my dynamic amp in to the chain.
 
Looking forward to it...
 
If you end up using just the Koss energizer, you might check out this 9V 3.00A regulated AC adapter that according to others makes a fairly significant difference in sound over the stock wall wart .. here is what I'm talking about: AC ADAPTER
 
I bought one for mine but am going to just store it with the Koss amp as I'll be using the Stax 252S for main duty.
 
Haven't had a chance to try the AC adapter as my Koss kit arrived with that distortion but when I get it back from Koss, I'm going to compare it to the wall wart.
 
Just a thought ...

 

[s1rrah]

Not sure how active this thread is but thought I'd mention this...
 
I'm selling a brand new Stax SRM-252S amplifier in the for sale/trade forum. It's an outstanding little amp and far and away better than the Koss stock energizer (many times better). In fact, it sounds just about as good as the SRM-323S at reasonable listening levels but the 323S over takes it when pushing much higher volumes and hard to drive electrostat cans.
 
I've only had it a few days and am only selling it cause I immediately re invested in a SRM-323S, which costs over twice as much as the 252S. 
 
Anyway, I plan on simply returning it to Headamp.com for a refund but am trying to sell it here first as I can offer a good deal to somebody and then Headamp could keep their money too (everybody wins).
 
So check the thread and let me know if your interested. Make an offer if the price isn't to your liking:
 
http://www.head-fi.org/t/696062/stax-srm-252s-brand-new
 
...
 
FYI.

 

[purk]

For those who want to make their own Koss to Stax adapter, Moon-audio sells the connector for $15 + shipping charge.
 
http://www.moon-audio.com/stax-cable-mount-5-pin-din.html#
 
I made my adapter earlier today and the Koss sounded like a different headphones out of my BHSE.

 

[AlanHell]

 you know where to get the extra extension cable?
I am also trying to make one, but want to keep the old connector too~~
 
I tired phoning Koss, and they tend not pick up their phone when it is close to holiday

 

[purk]

   you know where to get the extra extension cable?
I am also trying to make one, but want to keep the old connector too~~
 
I tired phoning Koss, and they tend not pick up their phone when it is close to holiday

Just try a little harder.  My extension cord was ordered directly from Koss for $15 + shipping charge.  I always wonder how Koss makes any profit from their sales.  My adapter is made from the extension cable as well. 

 

[s1rrah]

  For those who want to make their own Koss to Stax adapter, Moon-audio sells the connector for $15 + shipping charge.
 
http://www.moon-audio.com/stax-cable-mount-5-pin-din.html#
 
I made my adapter earlier today and the Koss sounded like a different headphones out of my BHSE.

 
Hell yeah.

 

[Gary in MD]

1.  Is there a wiring diagram that shows which wires go to which pins?
 
2.  How are the connections made in that connector?  Solder?  Push in and set-screw?  I saw a set-screw on the side... is that all that is needed (I doubt it, but I can hope, right...)?
 
If it's really easy I might even try it myself, but I am truly soldering-challenged.

 

[purk]

  1.  Is there a wiring diagram that shows which wires go to which pins?
 
2.  How are the connections made in that connector?  Solder?  Push in and set-screw?  I saw a set-screw on the side... is that all that is needed (I doubt it, but I can hope, right...)?
 
If it's really easy I might even try it myself, but I am truly soldering-challenged.

Here are links to the wiring diagram thanks to Wikiphonia.  You will have to match Koss to Stax pin-outs.
 
http://wiki.faust3d.com/wiki/index.php?title=ImageinOut_ESP950.jpg
 
http://wiki.faust3d.com/wiki/images/f/f0/Stax_Headphone_Cable_Connectors.jpg
 
It will require a decent soldering skill.  I advise you to get a spare stax connectors in case of any mistake.  You will have to strip the wire to expose a bare copper, match the pin out, and solder the wiring to each pin.  Finally, you will need to use multi-meter to check for continuity of each connection and double check again to be sure.  It isn't easy but give it a try as you can easily save $100.

 

[spritzer]

Also make sure to remove the Kevlar threads inside the cable before tinning it.  You can burn them off but make sure you clean the copper before soldering. 

 

[satwilson]

  I got that 9V 3.00A regulated AC adapter today, and I have to say it does address my biggest concern on the transparency. While it's still not the last word in transparency, it's definitely helped a noticeable amount, especially for fast-paced, congested tracks like rock music. For $30, it's definitely worth considering.
 
Also for fun, I hooked up a subwoofer and with crossover at 100 Hz to compensate for the bass roll off. Defeated the purpose of headphones not disturbing others, but it sounds pretty good.

Only the bass having a much larger soundstage and slower is a bit odd and takes away from the coherency of the overall sound.

I am glad to hear you also hear an improvement in sound using the upgraded power supply. I mentioned this back on post #1176. The other thing I found really improves the sound is to increase the input voltage. See some of my previous posts for details. On another thing, I am puzzled why some owners overlook these two simple upgrades and assume the "best" improvement is a Stax amp. Some people who have posted in this thread think the Stax is an improvement and others don't, so in my opinion there is no "consensus" the Stax amp is better. Please read the entire thread for the various opinions if you need to verify.

 

[purk]

 
I am glad to hear you also hear an improvement in sound using the upgraded power supply. I mentioned this back on post #1176. The other thing I found really improves the sound is to increase the input voltage. See some of my previous posts for details. On another thing, I am puzzled why some owners overlook these two simple upgrades and assume the "best" improvement is a Stax amp. Some people who have posted in this thread think the Stax is an improvement and others don't, so in my opinion there is no "consensus" the Stax amp is better. Please read the entire thread for the various opinions if you need to verify.

Thanks for your advice.  However, there are many Stax amplifiers ranging from a basic to extremely expensive ones.  I'm sure the Koss will behave best with ones with higher voltage swing such as the SRM-323S or 717.

 

[satwilson]

  Thanks for your advice.  However, there are many Stax amplifiers ranging from a basic to extremely expensive ones.  I'm sure the Koss will behave best with ones with higher voltage swing such as the SRM-323S or 717.

I am certainly aware of the various Stax amps and agree the two you mention are worthy, however the lower end amps may not provide any improvement if any over the E90. My point was more to the improvement that can be had for a cheap power supply upgrade and increasing the input voltage. That being said I certainly agree the E90 is not the best amp for the 950's, but for me right now monetarily the 950/E90 combo sounds great. When my budget allows either the McAlister or one of  KGs amp would be my choice.

 

[s1rrah]

After three weeks of waiting, I finally got my ESP-90 system back from Koss...
 
I had sent it in initially after buying it used off of Amazon and finding after it arrived that it had a pretty bad, low frequency distortion in the right channel; pretty sh1tty of the seller cause he basically admitted he had heard it too but always thought it was just a natural flaw of the Koss energizer and that he never heard it with his Blue Hawaii amp ... 
 
Anyway ... Koss fixed it up right nice and it sounds perfect. Here's the notes Koss' repair department made on the return invoice; can any of you more technical folk explain this?
 
...
 

 
...
 
Whatever it is, it worked ... so I'm happy. With the Koss amp, the headphones sound perfect, no buzzing, no distortion, no squealing just perfect. And, believe it or not, I'm rather surprised at how good the Koss energizer sounds when demo'ing back and forth with the my new Stax SRM-323S amp.
 
With the Stax amp, things are a touch brighter, a touch more detailed, better separation of instruments and a touch more bass impact. Also, the Stax amp, on tracks with lots of silence between other sounds, has a noticeably better, more 3D sound stage ... just more articulate. Another thing I noticed about the Koss energizer and specifically on electronic tracks with very heavily produced bass elements (think Gaudi or Kaya Project) ... was that at higher volume levels and as you push the Koss amp, a bit of distortion in the lower bass begins to show. With the Stax amp, this distortion does not exist and you can push the volume further (but really, it's getting to pretty loud listening levels at this point and so such tracks are enjoyable with either amp, just more headroom with the Stax amp.
 
But again, I'm totally surprised that the Koss energizer is just mere steps behind the Stax 323S in *everything*; it also, overall, has a slightly warmer sound. The SRM-323S is only about 30 minutes old/in-use at the time of the listening but I have no idea if that means anything or not.
 
BTW: when doing those comparisons and making those brief assessments, I was using the Koss energizer with a 3rd party 9V 3.00A regulated AC adapter; here is the one I am using: AC ADAPTER 
 
...
 

 
 
...
 
Ear speaker comparisons:
 
Some other words re: my Stax SR-307 earspeakers and the Koss earspeakers; for the following comments, I was listening to both headphones via my SRM-323s amplifier.
 
Here, just speaking of the two headphones sound sigs, I found the differences to be much more dramatic:
 
SR-307 Ear speakers: a good bit more articulate and detailed, more resolving and transparent. More refined. Tad better sound stage. Also, more "cold" sounding across the board; this last bit is not necessarily unpleasant but would amount to a matter of taste. The highs are better in the SR-307's, more sparkle. The Koss earspeakers, in comparison, sound quite rolled off in the high frequencies. 
 
Koss ESP-950 Ear speakers: a much "warmer" sounding headphone, more "musical" and easy on the ears. Bass at times sounds more prominent maybe but could be imagination. Also, the Koss headphones are less detailed and multiple sounds are a bit more "blended" together ... some might call this "congested." But it's a more musical headphone than the SR-307 to my ear and yields itself to more enjoyable and casual listening whereas the SR-307's sound more "reference."
 
...
 
Overall, I couldn't be more pleased with the Koss ESP-950. It's an incredible value, even with the stock amp, which is surprisingly capable; all of that goodness, even at it's list price of $999.99 is still a fantastic value. Find one for $600.00 bucks and it's a genuine steal.
 
Can't say enough about the portability of the whole kit, either, what with the nice, compact bag it comes with and all. Just an insanely good travel piece that could easily be driven from an Ipod or otherwise.
 
And lastly, the Koss lifetime warranty just sweetens the pot; like I said, mine arrived from my Amazon purchase with that horrible distortion in the right channel and so, crushed, I had to (the same day I got it from that Amazon seller, send it straight off to Koss for repair). Today, three weeks or so after sending it in ... it arrived back, with repair notes and everything, and sounds bloody brilliant. It's a super musical kit and just detailed enough to be considered edge of "reference" quality listening. Super fun to listen too ... zero fatigue/etch in anything you can throw at it.
 
I hope Koss never goes out of business cause I'll probably be keeping this kit forever. I'll use it with my Stax amp as it sounds just 10% better in all regards but it's nice to know that the very capable Koss energizer is in the bag for backup if I need it.
 
Just thought I'd share a few of those things...
 
Happy listening.
 

 

[DefQon]

Is that a Stockholm or Havana dac? Any good with the stats? (or in general)..

 

[purk]

  Is that a Stockholm or Havana dac? Any good with the stats? (or in general)..

I had the Havana but not the Stockholm with Ericson 2C51 gold pin and thought that it was a good DAC but it is missing in resolution & solid imaging.  It maybe too warm sounding for the Koss.  s1rrah what do you think?