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Koss ESP/950: At wits end

post #1 of 14
Thread Starter 
Well, I'm officially completely fed up. I'm on my fourth pair of brand new ESP/950s. Every one had/has the static and squealing problem; this fourth pair is the worst yet. The second I flicked 'on' the noises started and they haven't let up for a second.

The old advice of 'yeah, some have that issue-- just return them to Koss and they'll replace them' is useless when every pair Koss sends back has exactly the same problem. I'm out $800 (having bought in January--- too late to send them back now). I'm literally ready to throw them out the window at the first person who offers $15. This is just disgracefully bad QC.

Any ideas? The squealing and static makes them completely unusable.
post #2 of 14
I will gladly buy these for 15.
post #3 of 14
Thread Starter 
I'm still open to better ideas first--- but you might just get 'em for that.

OK, more editing...

This is a very simple design. There can only be a few places this is going wrong, let me keep looking for a bit.
Edited by xiphmont - 5/21/13 at 7:42pm
post #4 of 14
Thread Starter 
Yeah, looks like the driver assembly is permanently bonded together-- not surprising. No messing with that.

It appears to be a styrene or similar injection molded assembly in two halves, each of which is silvered in two separately conductive sections, with the conductive diaphragm sandwiched between. It appears the silvering on these is sloppy; there's some overspray or something on the inside, I'm guessing that's leaking given the voltage. So... I'm just screwed. The drivers are ****ed from sloppy manufacture, just like the previous pairs.

Oh, and they helpfully stripped out two of the screws in the right cup.

What a fustercluck. So. Very. Disappointed.
post #5 of 14
I know we're all different, but I'd personally play it patient and fully take advantage of their lifetime warranty until you get a good one. As far as I know it's the only headphone with such a coverage, and it can compete with the worlds best for sound quality. I might even tell them to test their replacement and make sure it doesn't squeal. That's only if you love the sound though. If you don't know if you'd like others, there's a whole rainbow of sound signatures out there.
post #6 of 14
Thread Starter 
In fact I do like the sound. I'm just worried that after four pairs, the liklihood of getting as good pair is shrinking. Not to mention I'm paying shipping for the whole shebang each time.

If I knew for sure I'd have to go through this eight times but I'm certain to get a good one-- well, I'd stick with it. But opening up the cans and peering inside, the manufacturing of the drivers doesn't really look that great (even if the design itself looks both sound and clever), and the soldering job also didn't inspire confidence. I suppose I can try at least once more :-(
post #7 of 14
Ouch. If you're having to pay more than like 10 or so per shipment, I'd fefinitely contact them about the situation. Surely a company already lenient enough to offer a warranty of that magnitude can go an extra step and work with you to prevent excessive shipping costs over time.
post #8 of 14

Might wanna consult existing ESP950 owners in a proper ESP950 thread, they would have more knowledge to help ya out / troubleshoot.

post #9 of 14

What a drag. Really sorry to hear. Are they testing them prior to send out ?


This is the direct Summit-fi dedicated thread to check in with may help somewhat.



post #10 of 14
Thread Starter 
Well, after disassembling things and deciding not to muck around with them (I have a good guess with what went wrong in the manufacture/assembly, and I have no chance in heck of fixing it), I complained politely to Koss and they've sent me a prepaid mailing label to return them. Again.

I like the design I saw inside. In fact I think the design is absolutely bloody ingenious. It's too bad they're having trouble making it consistently... which is weird, because the beauty of the design is how simple/easy it looks like it is to make. Aside from the diaphragm material, I'm pretty sure I could turn out an exact copy of the driver element in my basement shop in a night. That diaphragm though....

Anyway, I'll try one more time :-/
post #11 of 14

Koss products is not exactly known for quality, hence the "Lifetime warranty" they've been offering since the late 70's for all there headphones.

post #12 of 14
Thread Starter 
I collect vintage headphones; quality of earlier Koss stuff (60s and 70s) was great except for some rotten luck: cutting-edge space-age materials that turned out not to hold up. The specific foam formulations they used broke down, and the soft vinyls lost the plasticizers. I doubt they could have seen that coming on a 30-40 year timescale.

Of course then they imploded in the 80s and things have not been so great since.

I have a fantasy now-- enough cash to outright buy control of Koss and fix the manufacturing QC problems. Silly dreams.

[their earliest headphones had relatively little materials problems. The pro/4A especially seems to have escaped the bad foam and bad vinyl issues.]
post #13 of 14

Another reason why I would never pay $999 for the ESP950. After having one in my system for 2 days, I would pay for one at most of $450-500. Not only does it look cheap but feels really flimsy, now there is reported problems of transducer squealing. They are good stat's though, I give you that.

post #14 of 14
Thread Starter 
Having disassembled one as far as I could without crossing the point of no return, it's definitely a design that strives to be simple and easy to make. I can't think of any aspect I'd call deficient or flimsy. My guess is the squeal flaw is very simple-- from what I can see in this pair, the application of the conductive layer to the stator surfaces 'oversprayed'. That's just a smack-your-forehead manufacturing defect. It's not a problem that crops up, it happens straight out of the box.

Personally, I don't see the choice of ABS (and styrene internals) over aluminum and wood as being inappropriate. Acoustically, it's going to behave better and it's lighter. It's also much much less pretentious.

I agree that if Koss got their ducks in a row, this headphone could be sold for much less, and it doesn't have the same 'what the heck?' DIY-type finishing errors the hifiman cans tend to have... though to be fair to hifiman, I'm betting their return rates are lower ;-)

...and I meant it. If I could find a source of 1-2micron mylar, I'd make a go at reproducing these cans in my shop. Damn, now I really really want to buy Koss. I wonder how much I could get on Kickstarter...
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