[HeadphoneAddict]

Glad to hear they made it back okay!

 

[Bullseye]

Have to revive this thread.

I have checked that both left and right driver squeal when they are connected to the driver unit (either E/90 or SRM-323). They squeal more with the latter, though. It is because the drivers charge up, however stax doesn't do that.

The I asked this in the stax thread, but wanted to know for european koss esp-950 users what was your experience with the warranty and what did you say in order to give them notice and ask for help?

 

[padam]

Just get in touch with the European representative they will give all the details:

Simona Vanin

KOSS Europe
Centro Commerciale
CH-6855 Stabio
Switzerland.
Tel: ++41-91-641 61 20
Fax: ++41-91-641 61 29
E-Mail: svanin@koss.com

They even pay for the shipping and you don't have to worry about customs either.


By the way, the squeal gone away in my set when I just blew on the drivers from the sides.

 

[Bullseye]

Köszönöm!

 

[M3NTAL]

Just received my "new to me" set - fresh from Koss.

I've already noticed a couple things "odd" about them. One is, the foam inside the ear cup rubs on your ears unless you are perfectly still and creates a bothersome scratchy noise. The other thing I noticed is that they are literally shocking! Static build up from movement zapped me right in the dang ears!

I can see how some feel the amp is the biggest draw back. It defiantly can be driven into clipping pretty easily with some dynamic passages.

Overall the sonic characteristics are very interesting. They defiantly are not offensive and are relatively flat through the frequency response. I think the issues in the lower registers could be taken care of by an amplifier that had some grunt to it.

They are very light and pretty comfortable to wear so far. I'm not sure how I feel about build quality yet. One side of me thinks they are a little flimsy, but the most important part of them, the actual ear speaker unit, is solid. Mostly my issue is with the head band and attachment points.

Has anyone come up with something non-invasive to make finding left and right in the dark a little easier?

What sort of improvements are realized with better amplification? I wouldn't mind scaling these up and see what they have to offer.

-Cheers-

 

[jcx]

opened up the K/90, have 2.5KV probe at work - switcher frequency ~ 83KHz
+/- 600 Vsupplies have ~1 Vpp sawtooth ripple
probe loads bias V too much for meaningful measurement
edit: looks like just the V+ == output supply +600 V is also used for bias with 2x 10 Meg R feeding 22nF film cap on bias output - I think bias really should be higher than the max drive V

purchased new this year so should be pretty current:

 

[spritzer]

Do check the bias before the ballast resistor or you won't get an accurate reading without using a VTVM. Could you also find the value of the ballast resitor and post it?

 

[M3NTAL]

Bump - could someone take a look at my post ( I know the huge photos below my post took my posts steam )

I'm very curious about "up-grades". I know about using the stax amplifiers and re-terminating, but I would also like to go the DIY route with an amp built for them if it truly makes an improvement.

My main disappointment seems to be that the bass is easily muddled by complex passages and low end extension seems to be cut a tad short.

 

[dub]

Does anybody know something about a Koss ESP8 electrostatic stereophone that was releised in 1969?

 

[edstrelow]

There are lots of discussions of these phones sounding better of other amps, especially the many Stax amps. You can also get more out of the Koss amp with a bigger power supply. I used to use a 3amp bench upply.


Quote:

Originally Posted by M3NTAL /img/forum/go_quote.gif Just received my "new to me" set - fresh from Koss. I've already noticed a couple things "odd" about them. One is, the foam inside the ear cup rubs on your ears unless you are perfectly still and creates a bothersome scratchy noise. The other thing I noticed is that they are literally shocking! Static build up from movement zapped me right in the dang ears! I can see how some feel the amp is the biggest draw back. It defiantly can be driven into clipping pretty easily with some dynamic passages. Overall the sonic characteristics are very interesting. They defiantly are not offensive and are relatively flat through the frequency response. I think the issues in the lower registers could be taken care of by an amplifier that had some grunt to it. They are very light and pretty comfortable to wear so far. I'm not sure how I feel about build quality yet. One side of me thinks they are a little flimsy, but the most important part of them, the actual ear speaker unit, is solid. Mostly my issue is with the head band and attachment points. Has anyone come up with something non-invasive to make finding left and right in the dark a little easier? What sort of improvements are realized with better amplification? I wouldn't mind scaling these up and see what they have to offer. -Cheers-

 

[dub]

On the picts:









you can see ESP 8 — not 6 or 7 or 9 or 10:

can find any détails about these

 

[spritzer]

Looks like an upgraded version of the ESP7 which had the ESP6 electronics in an external box.

 

[dub]

I'll let you know when I'll have received it - it should be shipped today

 

[wualta]

Everything except the color and the barrier strip looks just like the SE.7 and the ESP.7. Possibly a version of the 7 for language labs or music libraries? Interesting.

 

[edstrelow]

The ESP8 doesn't even make it into the history pages on the Koss website!