KOSS ESP-950 Thread

[edstrelow]

Quote:

I have heard about this "squeal."  My ESP 950's don't do that. I think that some do, and some don't.  My original pair of ESP-9's used to have a little of this (in 1970...)  It sounded like arcing or static discharge of some sort, very very quiet but still audible.  If I jiggled the plug it would stop, and usually not come back for a long time.
 
Yeah they are "plasticky" in terms of construction but the fit and finish is good -   for plastic. But, being plastic, they are also very lightweight and quite comfy.  And even though they are plastic, they seem quite sturdy.
 
The earpads are leather.  Which you don't get on most Stax....
 
Hey!  Maybe that's it!  The earpads might be made of pigskin leather, hence the squealing....  

 

I had a set for many years and thought they were better than the lower ranked lambdas especially when run from a Stax amp, which I recommend.  As regards the squeal, mine  was fixed by opening the cups and pulling the cable a bit further away from the visible electrode.  In other words the electrode was very close to the cable and would short even against the plastic cable. I could actually see the sparks in the dark.  Very low level but still visible.  It is bizarre that Koss hasn't been able to fix this after years of complaints. 
 
I finally sold mine but still have an ESP 6 and ESP 9 which being wholely sealed are good in noisey conditions.  I never managed to get the 9 to run off a Stax amp.  I can'tfigure out what to do with the circuit board in the cups. Should one keep it in or just ditch it?  I know there is a problem about the common ground, when used with many amps.

 

[spritzer]

The circuit boards have to be completely bypassed on the ESP9 for it to work off a Stax amp.  Even then you have to work around the completely different diaphragm setup and it's bias. 

 

[milosz]

Quote:

The circuit boards have to be completely bypassed on the ESP9 for it to work off a Stax amp.  Even then you have to work around the completely different diaphragm setup and it's bias. 

And when you do that, what do you end up with?  How's it sound, compared to the E9 transformer / bias supply?  Is it worth the trouble?
 
I remember thinking that my ESP-9's in 1972 sounded SOOOOO great, and I suppose compared to the other phones of the day, they did.  But BOY were they uncomfortable!  What was Koss thinking with those very stiff silicone goop- filled earpads?  I suppose they are very good at sealing out outside noise, but they feel like something the CIA would use to get a terrorist to talk.

 

[spritzer]

It's been way too long since I was playing with the ESP's but the presentation is very different from the stock Koss setup.  I compensated by altering the damping but there was a lot of "processing" going on in the Koss box. 

 

[Reticuli2]

Do both the 6 and 9 use silicone-filled earpads and have about the same attenuation of outside noise?

 

[milosz]

Quote:

Do both the 6 and 9 use silicone-filled earpads and have about the same attenuation of outside noise?

I think the ESP-6 and ESP-9 used the same earpads as the Koss Pro-4AA.  I think they ALL have the same level of isolation, within a small margin.
 
Some variant of these silicone-filled earpads are still being made, the Pro-4AA remains on sale by Koss.  It is my understanding that the Pro-4AA earpads fit the ESP-9 & ESP-6.
 
So, if you wanted to get replacement earpads for your 40 year old ESP-9's, it's no problem, Koss will sell you a set at a reasonable price.  Compare that to other manufacturers- I contacted Beyer for replacement earpads for my Beyer ET-1000 electrostatic headphones  and they said "Sorry- no."

 

[ESL-1]

Good to see some recent comments on the ESP-950's. I have owned a second hand set for several years now and find their sound quite neutral, clean, open and reasonably quick. Although mostly plastic, construction quality is actually pretty good and as stated they are light and comfortable to wear for long periods of time. I would consider them a good value in the $400 - $600 price range. I have a set of ESP-9's as a reminder of the "old days" but the heavy headclamp effect limits my exposure to short bouts of nostalgia. Their sound, although good for their day is very different and was greatly surpassed when Stax introduced their SRX and then SRX MkIII's in my opinion. I was selling HiFi gear back then and purchased my first set of the SRX MkIII's which began my addiction to all things headphone.

To put things in perspective I currently still have a set of the Stax SRX Mk3 along with SR- Lambda's and SR-5's, Grado RS-1 (1997-98 vintage purchased new), PS500, SR-125, GR10, Beyer DT-880 and Paridigm e3m to name a few.

Oh btw, bought a set of replacement ear pads for the ESP-950's not that long ago, $5 which I think may have included shipping, could generate a case of reverse snobbery perhaps.....

 

[Reticuli2]

[size=10pt]I will probably buy another pair when the price comes back down. The ones I used for a week had the hum & channel imbalance. Koss hung up once on me and then didn't return my calls later. Strange. I just told the customer service lady what was going on and asked to talk to a tech who might know if it was normal. Their replacement policy is the customer service that's important, obviously. I wanted to just get a replacement from Amazon, but they would have needed to send it to Tyll again, who I didn't want to bug.  [/size][size=medium]Old warm analog recordings sound too warm on it and the ER4S and DT1350 have vastly superior bass.[/size][size=10pt] I miss the delicacy of the ESP. It's hard to go back to other headphones after getting used to them. I think I will sell some others to make room and assuage the guilt of owning such an expensive pair   I think I could live with just the ER4S, the ESP950, the sporta pros, and my isolation djing headphones.  That covers all the bases for me.[/size]

 

[AudioCats]

the 950 will benefit quite a bit from a recable, to open up the stage and improve details.
 
But since these phones tend to have reliability issues (intermittent static noise) which means you might have to send them back to Koss sometime down the road, it might not be a good idea to recable them. Plus, dust might get introduced into the ear cup during the recabling, and the drivers don't have rear dust cover......

 

[jcx]

 
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of course as an engineer I think most of the cable commentary is silly for any headphone - but do you people realize just how different the operating conditions for ES headphones are?
 
if a cable were to make a difference an engineer would expect this to mean there was a audibly significant voltage difference between one end and the other
 
in case you hadn't noticed the Stax voltage sensitivity number is ~ 100x less than your typical dynamic headphone - which might lead an engineer to suggest any voltage difference across the cable from wire composition has about 100x less influence on ES sound
 
then you need to consider that any cable V drop is also going to dependent on current - at average listening levels, for typical 3 KHz power bandwidth music signal the Stax draw another factor of 10-100x less current than dynamic headphones
 
just to be conservative in piling on the estimates suppose we say cable wire metal in ES headphones is 100 x 10 ~= 1000 less important than it would be for say K70x, much less an ortho
 
 
 
the special conditions of low capacitance and safety required double insulation mean you'd be nuts to buy a 3rd party ES cable anyway

 

 

[Anaxilus]

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Usually the ESP950 recable is with a Stax cable and thus a Stax termination.  Ergo, it's getting plugged into a Stax box not the Koss brick.  I'm not sure what anyone can deduce from that about the inherent effect of the cabling alone.  A lot of bold claims from poor method.  Not to say it doesn't exist, I certainly call into question the observation.

 

[sennheiserhd485]

Hi all,
 
What is a nice, cheap Stax amp that I could use with the Koss (new)?
 
Also, is it possible to buy the headphone without the energizer (new, of course)?
 
Thanks

 

[milosz]

Quote:

Hi all,
 
What is a nice, cheap Stax amp that I could use with the Koss (new)?
 
Also, is it possible to buy the headphone without the energizer (new, of course)?
 
Thanks

Call Koss and ask them if they sell the 'phone without the amp. 1-800-872-5677
I have never seen it advertised on Amazon etc as just the 'phones, so I'm guessing if it's available at all as just the headphones, it would have to come direct from Koss.
 
 

 

[AudioCats]

Quote:

Hi all,
 
What is a nice, cheap Stax amp that I could use with the Koss (new)?
 
Also, is it possible to buy the headphone without the energizer (new, of course)?
 
Thanks

950 requires pro-bias, and it is not particularly easy to drive, so maybe a SRM-3?
 

 

[AudioCats]

Quote:

Usually the ESP950 recable is with a Stax cable and thus a Stax termination.  Ergo, it's getting plugged into a Stax box not the Koss brick.  I'm not sure what anyone can deduce from that about the inherent effect of the cabling alone.  A lot of bold claims from poor method.  Not to say it doesn't exist, I certainly call into question the observation.

Have not done any instrumental measurement on the effect of recabling, but HeadphoneAddict did say my recabled Jade sound differently to his stock pair (at the 2010 Denver meet), so I supposed recabling can change the sound. Now whether it is worth the trouble to recable the 950 is a different story.