[Binge]

I continue to be surprised by these cans.  Great find with them on Full Compass!  Koss sends out a 20% discount coupon to me about once every month, and that was just signing up for the newsletter.
 
At $600 these headphones are the absolute greatest phone the money can buy.  Heavily opinionated statement as I do not normally get emotional over recordings like I would over a live set, but the 950s really put me in a place where I enjoy the music greatly!

 

[HiFiGuy528]

+1, these are a real gem.
 

 

[Andykong]

I continue to be surprised by these cans.  Great find with them on Full Compass!  Koss sends out a 20% discount coupon to me about once every month, and that was just signing up for the newsletter.

At $600 these headphones are the absolute greatest phone the money can buy.  Heavily opinionated statement as I do not normally get emotional over recordings like I would over a live set, but the 950s really put me in a place where I enjoy the music greatly!

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

 

[Sonido]

I'm looking to sell mine that I got during the cyber Monday sale last year for $500. I bought it at $600 at the time. I'll include the adapter upgrade as well. I'll create an official listing later today with pictures and link it here.

 

[Buddhahacker]

I'm looking to sell mine that I got during the cyber Monday sale last year for $500. I bought it at $600 at the time. I'll include the adapter upgrade as well. I'll create an official listing later today with pictures and link it here.

What adapter upgrade are you referring?

 

[Sonido]

What adapter upgrade are you referring?

http://www.head-fi.org/t/581491/koss-esp-950-thread/1260#post_10067372

 

[Buddhahacker]

http://www.head-fi.org/t/581491/koss-esp-950-thread/1260#post_10067372

Thanks. I don't have any distortion so I never tried the power supply replacement.  I was hoping you had a Stax adapter.  Someone was selling them a few years ago.  Someday if I get adventurous I might try to solder my own.

The Buddha.

 

[Andykong]

I'm looking to sell mine that I got during the cyber Monday sale last year for $500. I bought it at $600 at the time. I'll include the adapter upgrade as well. I'll create an official listing later today with pictures and link it here.

I am interested, shall we discuss on PM?

 

[satwilson]

  Thanks. I don't have any distortion so I never tried the power supply replacement.  I was hoping you had a Stax adapter.  Someone was selling them a few years ago.  Someday if I get adventurous I might try to solder my own.

The Buddha.

I am the person who suggested the Mouser power supply upgrade based on PM's with Kevin Gilmore. It is not to reduce distortion but allows the energizer to have better transient response, better bass, overall better sound than the stock wall wart. IMHO a must have upgrade. satwilson

 

[Kokomo O]

I recently got the Mouser power supply that Satwilson suggested. To be honest, I don't think I hear any difference. But, I guess you never know when that congested piece of music will come along that tests the amp's capacity to drive the headphones, and then without knowing it you'll be glad it's there supplying more current than the stock supply. That said, I listened to lots of stuff, side by side with both supplies, that should have challenged the smaller and simpler stock supply, and just could not hear a difference.
 
I also just got a new pair of ear pads. Koss is amazing with the pricing on these--five bucks, and free shipping. Had to ask my 14 year old to install them. They're a lot stiffer than the originals, which he commented had pleather that was starting to crack. The foam inside the old pads had gotten much softer than the new ones, and therefore the drivers were much closer to my ears. If anyone's using old 950s with original pads, I'd recommend replacing them. Just find a kid with dexterity to do the job.
 
Koss or a third party manufacturer really ought to make pads out of real leather, and maybe a little deeper. 

 

[satwilson]

  I recently got the Mouser power supply that Satwilson suggested. To be honest, I don't think I hear any difference. But, I guess you never know when that congested piece of music will come along that tests the amp's capacity to drive the headphones, and then without knowing it you'll be glad it's there supplying more current than the stock supply. That said, I listened to lots of stuff, side by side with both supplies, that should have challenged the smaller and simpler stock supply, and just could not hear a difference.
 
I also just got a new pair of ear pads. Koss is amazing with the pricing on these--five bucks, and free shipping. Had to ask my 14 year old to install them. They're a lot stiffer than the originals, which he commented had pleather that was starting to crack. The foam inside the old pads had gotten much softer than the new ones, and therefore the drivers were much closer to my ears. If anyone's using old 950s with original pads, I'd recommend replacing them. Just find a kid with dexterity to do the job.
 
Koss or a third party manufacturer really ought to make pads out of real leather, and maybe a little deeper. 

I appreciate your comments and evaluation of the larger PS. The other thing I do with my setup is rather than a standard 2V line in to the E90 I use the variable out on my AudioGD NFB-12 DAC/amp to control the volume. I set the E90 at about 90% and then adjust the volume on the NFB-12, I estimate 3-3.5V into the E90. Line out voltage varies from some sources from 2-5V. The bigger power supply and hotter input signal are not my ideas but gleaned from other HeadFier's in various Koss 950 threads and posts. satwilson

 

[jcx]

just got a Koss promo email code: SPRING20 - 20% off appears to apply to esp-950 today - $800 isn't too bad recently
 
discounting in distribution seems to have become less deep, less frequent:
 
http://camelcamelcamel.com/Koss-160416-ESP-950-Electrostatic-Stereophone/product/B000056ULH?context=browse

 

[Kokomo O]

  I appreciate your comments and evaluation of the larger PS. The other thing I do with my setup is rather than a standard 2V line in to the E90 I use the variable out on my AudioGD NFB-12 DAC/amp to control the volume. I set the E90 at about 90% and then adjust the volume on the NFB-12, I estimate 3-3.5V into the E90. Line out voltage varies from some sources from 2-5V. The bigger power supply and hotter input signal are not my ideas but gleaned from other HeadFier's in various Koss 950 threads and posts. satwilson

Satwilson, I've been thinking about this post for a long time. My guess is that if you're setting the volume at 90% on the E90, you're actually not running very hot input into the E90--in fact, you're probably not running below the nominal 2V that many, maybe most, unpotted DACs claim they put out. With most DACs as inputs, I would think 90% volume on the E90 would be literally deafening. I know it would be with my ODAC. 
 
What got me concerned about your approach was that your estimate of running 3-3.5V into the E90 had me thinking that you were inadvertently generating overload into the input stage of the E90 at that relatively high voltage, which could lead to distortion. Perhaps this distortion would be audible, perhaps not, but if not you would probably still not want it. But then it occurred to me that you had so much gain on the E90 that you were probably actually turning your source down pretty far, far enough that you didn't have such high voltage, and therefore didn't have this problem I was thinking you had.
 
Anyway, if this is the way you choose to operate, why not remove the volume pot entirely, and replace it with a fixed resistor of appropriate value? This is what George Kaye does as part of his upgrade to the SuperIt phono preamp (replacing both the volume pot and the balance control). If you still wanted to have a volume controlled E90, or other amp for the ESP-950s, you could probably find an E90 on eBay or somewhere else, or get a Stax amp.

 

[satwilson]

  Satwilson, I've been thinking about this post for a long time. My guess is that if you're setting the volume at 90% on the E90, you're actually not running very hot input into the E90--in fact, you're probably not running below the nominal 2V that many, maybe most, unpotted DACs claim they put out. With most DACs as inputs, I would think 90% volume on the E90 would be literally deafening. I know it would be with my ODAC. 
 
What got me concerned about your approach was that your estimate of running 3-3.5V into the E90 had me thinking that you were inadvertently generating overload into the input stage of the E90 at that relatively high voltage, which could lead to distortion. Perhaps this distortion would be audible, perhaps not, but if not you would probably still not want it. But then it occurred to me that you had so much gain on the E90 that you were probably actually turning your source down pretty far, far enough that you didn't have such high voltage, and therefore didn't have this problem I was thinking you had.
 
Anyway, if this is the way you choose to operate, why not remove the volume pot entirely, and replace it with a fixed resistor of appropriate value? This is what George Kaye does as part of his upgrade to the SuperIt phono preamp (replacing both the volume pot and the balance control). If you still wanted to have a volume controlled E90, or other amp for the ESP-950s, you could probably find an E90 on eBay or somewhere else, or get a Stax amp.

Thanks for your analysis of my setup. I have to agree, running the E90@ 90%, the input signal could not be 3-3.5V. I made the mistake of assuming my variable out was 2-5V when in fact it is 0-5V. I am still curious as to why some report better sound with the upgraded PS and others don't. Perhaps running my E90@90% places more demand on available power supply? Some have reported better sound with the battery pack which has considerably greater current than the wallwart. I assume measuring the current draw of the E90 under load with the larger PS to see if it draws more than the wallwart provides would answer that question. I really like the sound of the 950's and have been exploring ways to tweak the stock setup on the cheap, but yes, a better amp is in the works when budget permits.

 

[Kokomo O]

  Thanks for your analysis of my setup. I have to agree, running the E90@ 90%, the input signal could not be 3-3.5V. I made the mistake of assuming my variable out was 2-5V when in fact it is 0-5V. I am still curious as to why some report better sound with the upgraded PS and others don't. Perhaps running my E90@90% places more demand on available power supply? Some have reported better sound with the battery pack which has considerably greater current than the wallwart. I assume measuring the current draw of the E90 under load with the larger PS to see if it draws more than the wallwart provides would answer that question. I really like the sound of the 950's and have been exploring ways to tweak the stock setup on the cheap, but yes, a better amp is in the works when budget permits.

Yes, funny how the mind works. I had been mulling this ever since you put up the post a month ago and had the "a-ha" moment last night.
 
I don't know about your hypothesis that running the E90 at 90% places more demand on available power supply. I suspect the key parameter is the maximum voltage of the output signal, and that's going to be the same no matter what, given the same listening level. But someone with more knowledge of electrical engineering than I have would have to answer that.
 
And yes, I too really like the 950s, always have. Granted, it's been a long, long time since I've heard any Stax or any other modern high-end headphones, electrostatic or otherwise--like about 20 years--but I liked the 950s better than any other headphones I heard back then. But I too have been thinking about what to do to upgrade when the budget permits. One thing I've obviously been considering is one of the various ES amp options. Another is the Woo WEE, along with an amp that works well for headphones, and also can drive speakers, so I could use the speaker taps for the WEE and the 950s. One of the amps I've been looking at for that purpose is the Bottlehead S.E.X., which looks like a relatively easy build I could do with my son, and also a great amp for any headphones. I wonder how it works for electrostatics out of the speaker taps through the WEE.