My ESP950's right earcup is hissing - help please
Jun 20, 2006 at 9:19 PM Thread Starter Post #1 of 10

Spiug31

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Hello all,
I have a problem with my newly acquired Koss ESP950's:

My right earcup is hissing - this hiss doesn't vary with volume nor is there any sign of hiss from my left earcup, apart from this issue both the earcups play music very well. I have searched for "koss, ESP950 and static / hiss" but found no clear answer to this problem.

Has anyone found a simple solution for this problem and is there a reason for its occurence ?

All help appreciated.


p.s. the ESP950's even with the hiss sound better than my Proline 750's so I'm really looking forward to getting rid of the hiss
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Jun 20, 2006 at 10:27 PM Post #2 of 10
Koss 'stats, unlike Stax ones, don't have dust covers on the rear of the drivers. If a bit of dust gets stuck even part of the way between the stators and the diaphram, it'll arc over and make a hissing sound. The HE60s also do this for the same reason.

There are two solutions:

First option is to get a vacuum cleaner with a varible level of suction, Starting with the suction level as low as possible, put the end of the vacuum on the back of the headphone (the part that is on the other side of the headphone from your head) so that it is close, but not quite touching the headphone and vacuum it. Slowly increase the suction making sure you don't go too high so as not to stretch or damage the diaphram or bend the stators (all the components in electrostats are very thin). Take your time and give the whole driver area a going over. Once you're done, plug it in and let the diaphram polarise for a while, and then give it a listen. You may, or may not have dislodged the gunk in there.

Second option is to send it back to Koss to get the diaphrams replaced. It has a lifetime warrenty, might as well use it.


Neither option will last forever. Unless you have an exceptionally dust free home, dust will begin making assults on the headphones again. To slow it down, putting some kind of dust cover over the headphones when they aren't in use is a good idea. Even a couple of sheets of cling rap over the backs of the earpieces will work.
 
Jun 20, 2006 at 11:11 PM Post #3 of 10
Not putting dust protection on the back of an electrostatic headphone seems a silly oversight to me, especially for a company with a lifetime warrenty policy. Is there some sort of sonic or technical merit in not doing so?
 
Jun 21, 2006 at 2:59 AM Post #5 of 10
I bought a reconditoned ESP/950 real cheap, and it had terrible distortion at higher volume settings. Back it went to Koss, under their lifetime warranty, and they replaced the energizer unit. It came back in perfect condition, and still works perfectly. I suggest that you send it to them.
 
Jun 21, 2006 at 4:53 AM Post #6 of 10
Quote:

Originally Posted by Duggeh
Not putting dust protection on the back of an electrostatic headphone seems a silly oversight to me, especially for a company with a lifetime warrenty policy. Is there some sort of sonic or technical merit in not doing so?


One of the biggest problems in designing an electrostatic is dealing with the out of phase backwave. Even a single sheet of mylar will reflect some of it back, which is why some stats escue using a dustcover on the outsides of the drivers. It's pretty easy to prove in practice that that ain't a smart idea, of course.
 
Jun 21, 2006 at 5:57 AM Post #7 of 10
Several years ago I discovered that the reason for the 950 noise, usually more a squeal than a hiss, was that the cord leading into the earcup ran too close to the brass (gold plated?) electrode on the diaphragm and caused some leakage. You could actually see a flow of sparks in dim light. The answer, pull the cord out a ways, I mean like another couple of mm. Not easily done though and you will have to open the cups to see and do this.

Now you say its more like hiss. Could be something else, possibly the dust as was suggested although I have personally never encountered the latter.
 
Jun 21, 2006 at 9:49 AM Post #8 of 10
The vacuum did have an effect and the hiss is diminished though as it repolarised it did squeal for a while. The remaining low volume hiss/squeal may be subtle enough for me to ignore once music is playing so I'll give it several more hours before I decide if its worth sending it off to Koss.
(I'm hoping I won't have to open up the phones.)
Thanks for the helpful suggestions.

Edit: I forwarded my headphones to Koss in the UK and they are sending them to America to get fixed - should be two weeks
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Jun 21, 2006 at 1:16 PM Post #9 of 10
if they dont get better send them off for repair.

there is no good reason to live with poorly functioning equiptment when it can be fixed cheaply. it does suck to be without your headphones for a couple weeks though.
 
Jul 3, 2006 at 5:24 PM Post #10 of 10
My headphones arrived back today and work very well, the hiss is completely gone and the only cost to me was the £8 (I used a large box
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) to send my headphones to the UK Koss distributor, really an excellent service.

Thankyou for all your help


now for more listening
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