[manywelps]

I'm getting an intermittent squeal/hiss in the right earphone.  It's obvious when there's no sound, and audible if I'm playing music at a low volume...
 
Back to koss for driver replacement?
 
Edit: really intermittent.  Only heard it 3 times today.

 

[ericj]

  I'm getting an intermittent squeal/hiss in the right earphone.  It's obvious when there's no sound, and audible if I'm playing music at a low volume...
 
Back to koss for driver replacement?
 
Edit: really intermittent.  Only heard it 3 times today.

 
If you are quite brave, sometimes this is just wires too close where they attach to the stators and diaphragm. or sometimes because sweat has worked it's way in there, and there is salt in the area. 
 
You can open them up and see how things are, maybe use a bit of fabric clenched in tweezers to clean things up if they seem to be corrupted. 
 
Or you can pay for shipping both ways with koss. Include the complete headphone (w/ headband) and the e/90. They will tune up the amp at the same time and return it with a fresh faceplate sticker. 

 

[manywelps]

These are brand new (<50 hours).
 
I tapped them with my hand and it stopped...  maybe something got in there.
 
If it doesn't stop, I'll send it to koss.
 
Edit: It came back and it's REALLY loud.  Tapping it gets it to change volume...
 
Edit2: tapping made it stop... no idea.

 

[dwest1023]

These are brand new (<50 hours).

I tapped them with my hand and it stopped...  maybe something got in there.

If it doesn't stop, I'll send it to koss.

Edit: It came back and it's REALLY loud.  Tapping it gets it to change volume...

Edit2: tapping made it stop... no idea.

Blow in the cups. I think dust gets in the earcups and causes the noise. I bought mine brand new a year ago, with the same noise issue. Blew in the earcups and no problem since. YMMV

 

[manywelps]

 

These are brand new (<50 hours).

I tapped them with my hand and it stopped...  maybe something got in there.

If it doesn't stop, I'll send it to koss.

Edit: It came back and it's REALLY loud.  Tapping it gets it to change volume...

Edit2: tapping made it stop... no idea.

Blow in the cups. I think dust gets in the earcups and causes the noise. I bought mine brand new a year ago, with the same noise issue. Blew in the earcups and no problem since. YMMV

That's kind of what I was thinking.
 
Where? Inside? Outside? both sides?

 

[AudioCats]

I suppose that is what the life-time warranty is for. The warranty is intended to be used, not just as bragging rights. 
 
Send them back and let Koss fix it..
 
 

 

[manywelps]

  I suppose that is what the life-time warranty is for. The warranty is intended to be used, not just as bragging rights. 
 
Send them back and let Koss fix it..
 
 
 

Yeah, I blew on it and it got much louder.
 
At least it won't cost much in shipping because the earpieces are crazy light.

 

[OJNeg]

A friend has Stax energizer (just a step up transformer + bias supply) that I'm going to try to mod for Koss use. I'll see how that turns out.

 

[ericj]

  A friend has Stax energizer (just a step up transformer + bias supply) that I'm going to try to mod for Koss use. I'll see how that turns out.

 
hope it's a pro energizer

 

[crazychile]

has anybody tried maxxing out the E90 (better opamps, better internal supply parts etc)?

Either earlier in this thread, or in another Koss (maybe even a Stax thread) I seem to remember that Kevin Gilmore or Spritzer mentioned that the parts in the E90 were actually pretty good. But I think the circuit design goal was to just make it work well enough and to keep the system price affordable.

My upgrade progression since owning theKoss' since last Fall has gone like this:

1. Upgraded the power cord and powersupply that feeds the E90. This made a noticeable improvement for a very reasonable price. You can search back through this thread for specifics. I' m leaning towards it was the power supply that made most of the improvement, the upgraded power cord I already had.

2. Drilled out the back plate of the E90 so I could get my cables to go on all the way. This didn't really change the sound but I felt better about it, and it cost me about 10 minutes of my time.

3. Started thinking I would eventually buy some SR-007s so I should be ready with an upgraded amp. Why not buy that first and see what it does with the Koss'? So I bought an upgraded Exstata from Spritzer, and built a Koss adapter cable. That made A little more improvement than when I upgraded the E90 power supply and cord, but at about 8x more money. The Exstata is on the low end of the "good" non-Stax amps at about the cost of an SRM-323.

Buying the better amp satisfied my curiosity about how much better the performance of the Koss' can be with a proper amp. The conclusion is that they get better, but you probably aren't going to have a holy sh!t moment.

I think someone has said it before, but the Koss' are like the gateway drug into electrostatics. You'll get a taste of what stats can do but probably want more... And then that'll cost ya.

 

[ardgedee]

I've been really impressed with the ESP 950 powered by a McIntosh MAC4100 through the Woo WEE. There's more treble and less bass punch (albeit plenty of extension) relative to the E90 amp, which is odd because the Mac can really bring a really tangible bass out of the HE-6.
 
I'll concede it's only cost efficient if you already have the Mac.

 

[doctorjazz]

has anybody tried maxxing out the E90 (better opamps, better internal supply parts etc)?

Either earlier in this thread, or in another Koss (maybe even a Stax thread) I seem to remember that Kevin Gilmore or Spritzer mentioned that the parts in the E90 were actually pretty good. But I think the circuit design goal was to just make it work well enough and to keep the system price affordable.

My upgrade progression since owning theKoss' since last Fall has gone like this:

1. Upgraded the power cord and powersupply that feeds the E90. This made a noticeable improvement for a very reasonable price. You can search back through this thread for specifics. I' m leaning towards it was the power supply that made most of the improvement, the upgraded power cord I already had.

2. Drilled out the back plate of the E90 so I could get my cables to go on all the way. This didn't really change the sound but I felt better about it, and it cost me about 10 minutes of my time.

3. Started thinking I would eventually buy some SR-007s so I should be ready with an upgraded amp. Why not buy that first and see what it does with the Koss'? So I bought an upgraded Exstata from Spritzer, and built a Koss adapter cable. That made A little more improvement than when I upgraded the E90 power supply and cord, but at about 8x more money. The Exstata is on the low end of the "good" non-Stax amps at about the cost of an SRM-323.

Buying the better amp satisfied my curiosity about how much better the performance of the Koss' can be with a proper amp. The conclusion is that they get better, but you probably aren't going to have a holy sh!t moment.

I think someone has said it before, but the Koss' are like the gateway drug into electrostatics. You'll get a taste of what stats can do but probably want more... And then that'll cost ya.

This sounds like my experience...I did the things Crazychile recommended early in the thread, power supply and power cord first, not sure how much the cord did, power supply was actually a significant upgrade sonically. Then I got the 323b (which I guess is not a prime Stax amp, who knew), got a bit of improvement, but I'd say the upgrade to the power supply was the biggest change sonically, at not too crazy a price.
Highs are where I think these Koss cans lose out in my set up.

 

[AudioCats]

 
Yeah, I blew on it and it got much louder.
 
At least it won't cost much in shipping because the earpieces are crazy light.

while you are at it, order some extra ear pads. The plastic top layer will start to flake off the fabric base material in about 5 year.
The pads are only $6, and  it never hurts to have brand new pads at hand just in case you might want to sell the 950 later. 

 

[ssrock64]

Well, it's happened, I'm back to a one-headphone main system. No matter what I buy or try, I can never quite shake the feeling that the ESP950 is as good as it gets for me. After owning an HD650 for a year, I've decided that Sennheiser's former flagship is about as close as a dynamic gets to the E90/ESP950 in terms of sound signature, but the Koss gets rid of the HD650's often frustrating slowness and heaviness of impulse response. The humble ESP950 is like a fusion of all the traits I liked about Grado's PS1000 (speed, air) and the HD650 (warmth, intimacy).
 
I guess it's time now to start looking into upgrading my E90, since it looks like I'm settled into one headphone for the forseeable future.

 

[RAZRr1275]

What's a decent, cheap cable you can use with that Mouser power supply?