[kleptolia]

Just got these today. Love them so far! One thing I notice, though, is an ever so slight rattle in the left ear on some, but not all, bass notes. The bass in these is far more powerful than I was expecting. It's very controlled, though.
Does anybody have any thoughts on these? Does that rattle I'm hearing mean they need a repair? It's the only "problem" with them that I can find. And it's not a serious problem. It's very faint and only on very heavy sounds, like an 808 kick.
I am planning to make these my main headphones so I also would like to know if there's anything I should watch out for, maintenance-wise.
I was going to buy a set of the Tony Bennett signature headphones because they are exactly like the Pro DJ100s, but with a detachable cable. These HV/1As were spoken of highly by some on this site and so when I saw a set for $40 on Craigslist, I grabbed them. Saved $20 between these and the Tony Bennett's, but I'm wondering if I should have just bought the new ones for the warranty.

 

[Retrovert]

... One thing I notice, though, is an ever so slight rattle in the left ear on some, but not all, bass notes. The bass in these is far more powerful than I was expecting. It's very controlled, though.
Does anybody have any thoughts on these? Does that rattle I'm hearing mean they need a repair?

Having just acquired a pair to replace the ones I listened to many years ago I did a pile of research on how to rebuild them.
 
The big issue seems to be the foam inside that disintegrates and clogs up the drivers.  This is, of course, the perennial problem with older headphones.
 
An excellent, and simple, guide to repair can be found here: http://www.audiokarma.org/forums/showthread.php?p=7508836
 
I know that mine have disintegrated foam and I haven't yet removed all of it and replaced it with something suitable.
 
If you have bits and pieces of decayed foam in your drivers that could account for the sonic weirdness.
 
Koss, by the way, will have replacement foam earpieces back in stock at the end of the month.  (I called to find out what "out of stock" meant in reality.)

 

[dwayniac]

Having just acquired a pair to replace the ones I listened to many years ago I did a pile of research on how to rebuild them.

The big issue seems to be the foam inside that disintegrates and clogs up the drivers.  This is, of course, the perennial problem with older headphones.

An excellent, and simple, guide to repair can be found here: http://www.audiokarma.org/forums/showthread.php?p=7508836

I know that mine have disintegrated foam and I haven't yet removed all of it and replaced it with something suitable.

If you have bits and pieces of decayed foam in your drivers that could account for the sonic weirdness.

Koss, by the way, will have replacement foam earpieces back in stock at the end of the month.  (I called to find out what "out of stock" meant in reality.)

A good alternative to the Koss pads are Grado L cushions made by Earzonk. They fit perfectly but they have to be glued on or use double sided tape.

 

[Retrovert]

dwayniac /img/forum/go_quote.gif
A good alternative to the Koss pads are Grado L cushions made by Earzonk. They fit perfectly but they have to be glued on or use double sided tape.

 
That is good to know.
 
The Koss ones are, I believe, $5 delivered, though.  Hard to beat that.

 

[dwayniac]

   
That is good to know.
 
The Koss ones are, I believe, $5 delivered, though.  Hard to beat that.

True. I live in Milwaukee so for me,delivery is free and fast. I just think the L cushions improved the sound quality to my ears. Better bass to be specific because the drivers sit closer to my ears.

 

[Retrovert]

dwayniac /img/forum/go_quote.gif

True. I live in Milwaukee so for me,delivery is free and fast. I just think the L cushions improved the sound quality to my ears. Better bass to be specific because the drivers sit closer to my ears.

Can't be next day delivery when paying for regular mail.
 
Your bass comment is an interesting observation, and I've been thinking about it.
 
Sound should not be lost in the intervening half inch, as the Koss foam cushion is simply not lossy enough to provide any significant signal attenuation.  That foam is acoustically dead and sufficiently solid to be  impermeable to much sound leakage.  Here's how you can test that.  Put them on your leg and see how much sound leaks out.  (I'd do it and report back, except, as I noted, I need new cushions, as well as to take my drivers apart to remove all of the deteriorated internal foam.)
 
My guess is that the shorter distance may make it slightly louder at the same volume level, and humans tend to pick the louder sound as better.  (This is how, many years ago, I ended up being sold a pair of Cerwin-Vega U123s instead of the smaller AR bookshelfs I wanted.) Or it might be that the more solid cushions more effectively isolate you from the room more so you get a more intense experience.  Other than that, I would think that cushion choice should be a comfort and aesthetic issue, not a sound one.

 

[dwayniac]

  Can't be next day delivery when paying for regular mail.
 
Your bass comment is an interesting observation, and I've been thinking about it.
 
Sound should not be lost in the intervening half inch, as the Koss foam cushion is simply not lossy enough to provide any significant signal attenuation.  That foam is acoustically dead and sufficiently solid to be  impermeable to much sound leakage.  Here's how you can test that.  Put them on your leg and see how much sound leaks out.  (I'd do it and report back, except, as I noted, I need new cushions, as well as to take my drivers apart to remove all of the deteriorated internal foam.)
 
My guess is that the shorter distance may make it slightly louder at the same volume level, and humans tend to pick the louder sound as better.  (This is how, many years ago, I ended up being sold a pair of Cerwin-Vega U123s instead of the smaller AR bookshelfs I wanted.) Or it might be that the more solid cushions more effectively isolate you from the room more so you get a more intense experience.  Other than that, I would think that cushion choice should be a comfort and aesthetic issue, not a sound one.

I never said anything about next day delivery. 
 
I tried the L cushions on a whim and on my ears,the L cushions cover them almost completely as opposed to the Koss cushions that are supra-aural. I heard enough of a difference to have a preference for them on the HV/1 for "better" sound,comfort and aesthetics. 

 

[Retrovert]

dwayniac /img/forum/go_quote.gifI never said anything about next day delivery. 

True, but as Koss is in Milwaukee, I figured how long can it take for a package to go from the post office to you since you're in the same city?  It normally takes only a few days after ordering to travel from Koss to me (or so it did when I bought a pair of covers a few years back), so its shipping is pretty fast.
 
Quote:

dwayniac /img/forum/go_quote.gif I tried the L cushions on a whim and on my ears,the L cushions cover them almost completely as opposed to the Koss cushions that are supra-aural. I heard enough of a difference to have a preference for them on the HV/1 for "better" sound,comfort and aesthetics. 

 
Hey, if you like the L cushions use them.  (Not that you need approval, of course, just saying listen to what thou wilt shall be the whole of the law.)  Was just commenting that the foams likely were not different enough to have different acoustic losses, and that placement was so close it couldn't matter much, so it had to be a different factor in the sound.  As a technical matter, not an aesthetic matter.  That's all.  I totally believe you and agree with you that cushions covering the ears sound very different; that's why I switched from an on-the-ear Sennheiser to an over-the-ear AKG.  I just find the over-the-ears to be a little hot and heavy for prolonged use, that's all.

 

[audio19]

I've owned a few pairs of these and that rattle is in the manufacturing. It's the power wires attached to the cones. Little I know of can be done about that aside from turning down the bass. These are after all high velocity headphones. It's part of their pros and cons. It makes them lifelike, but causes a rattle doing so.

 

[Retrovert]

I've owned a few pairs of these and that rattle is in the manufacturing. It's the power wires attached to the cones. Little I know of can be done about that aside from turning down the bass. These are after all high velocity headphones. It's part of their pros and cons. It makes them lifelike, but causes a rattle doing so.

Is this because the wires were once glued down to the cone and are no longer fixed in place?
 
Or is it that the wire is sort of hanging in space and hits the cone on the long excursion from the bass?
 
It might just be foam rattling around.  This posting ( http://www.head-fi.org/t/246812/parts-for-vintage-koss-stereophone-koss-tech-2 ) says that the foam construction for the Tech/2 driver was similar to the HV/1 driver.  Maybe it's just hard foam bits that vibrate?
 
Caution seems to apply when tinkering with the drivers.  See: http://www.head-fi.org/t/461765/repair-of-koss-hv-1

 

[audio19]

Yes to your second question.
I've never owned them that long where the foam pads disintegrate and particles clog or interference with cone movement? If it did? It wouldn't be a ticking sound I'm sure.
I have replaced pads because they go flat, not because of dry rot.

 

[Retrovert]

Yes to your second question.
I've never owned them that long where the foam pads disintegrate and particles clog or interference with cone movement? If it did? It wouldn't be a ticking sound I'm sure.
I have replaced pads because they go flat, not because of dry rot.

Mine were a replacement pair and had dry-rotted external foam.  I don't yet know about the internal foam.  The internal foam (damping foam?) is around the magnet, so if it has dried out, hardened, and shrunk, as well as detached from both the magnet and surrounding housing, it could be resonating or just vibrating at low frequencies.  See:
 

http://www.head-fi.org/t/593769/koss-realistic-pro-ii-headphones-one-side-dead-advice
this is _the_ common problem in Koss drivers of this era (along with damping foam disintegrating and getting into the magnet gap through the venting holes in the back, sometimes even corroding out the magnet).

 

[audio19]

I guess that's possible? But simply shaking the cups would result in pieces dislodge and falling out, you think?
Have you tried calling Koss customer service for refurbishing? I wouldn't try to disassemble them. They're built like tanks! I've tried and completely ruined a pair, and I consider myself pretty handy with a competent level of mechanical aptitude! I don't know your abilities, but they are glued permanatly shut.

Aside from all this Koss just needs to bring them back anniversary style like they did with their pro AA 4 a few years ago. Which never sound as good or sealed over the ears properly. Or how about Sennheizer's yellow padded 414s open back did. Those Hv-1A are clearly superior sounding to either of those two! Radio shack even had their version! Koss needs to really get on the ball with this headphones revival taking place! They're not even in the runnings?? Sorry Porta pro wearers. That just isn't their best offerings. I had 2 pairs of those until Sennheizer dropped those PX-100 ll which I now own instead! C'mon Koss, the sleeping giant needs to wake up!

 

[Retrovert]

I guess that's possible? But simply shaking the cups would result in pieces dislodge and falling out, you think?
Have you tried calling Koss customer service for refurbishing? I wouldn't try to disassemble them. They're built like tanks! I've tried and completely ruined a pair, and I consider myself pretty handy with a competent level of mechanical aptitude! I don't know your abilities, but they are glued permanatly shut.

The components of any audio system can vibrate.  I've heard rattle from vibration in all sorts of things that aren't audio.  If it's loose, any vibration will rattle it, and everything has a resonant frequency.  When foam shrinks and hardens, it often detaches and bounces around.  Can that cause this buzz?  I don't know.  But it wouldn't surprise me.  It wouldn't necessarily break up into pieces, could just be a big hard lump.   I hope someone who knows about the HV/1 will post some experiences and repair info.
 
I haven't taken mine apart for the very reasons you cite.  Seemed VERY unwise.
 
Here's how to put new scrim in on the LC model, which should be similar:
http://www.audiokarma.org/forums/showthread.php?t=569420
 
Koss does not, alas, service these.  The only part it has is new foam, which I bought.  I haven't had a chance to remove the old adhesive and put these on.

 

[Neighbour]

The voice coil wire isn't glued to the diaphragm.

One possible option is to buy the pro4aa and transplant the HV diaphragm with voice coil onto the pro4aa capsule. Koss redesigned the newer pro4aa capsule with a wire canal to eliminate direct wire contact to the diaphragm.

At all its try and error and if the current pro4aa magnet is stronger or the capsule slightly different from the dampening, the result could be better or bad.

The best way would be to glue the wire on the diaphragm.


A new HV version would be nice to buy. The same aluminium frame, a more aesthetic shell and a better padded Headband. Build on a soild, well known base and it would be worth 150-200$. The design and construction of the HV/1A is up to date worth its 100$.

There is only one problem. Koss made later far better drivers.

I've bought last time the new version of pro4aa. The capsule performance is limited and its outclassed with the introduction of the newer HV lightweight element back in the 80s. Maybe the old pro4aa HV/1 capsule design can match with some optimizations the DT880, HD650 and K701,but the old Koss element has some sort of technical sound signature. The lower bass is also soft textured.

The successor of the HV/1A is the (Realistic pro60) HV/x /pro. More resolution, a more natural sound signature with a natural body and air weighting on instrument reproduction. Koss downgrades the HV/x /pro on some low budget manufacturing process and a more refined K240 Sextett Sound signature with cinematic sound scape. Cleaning up the HV/pro sound with some modifications and its open up with holographic, pin point accurate and natural sense of space and air.

Latest notes on the oldest HV and pro4 drivers.
Rust on the magnet and yokes comes from bad handling and storage.The magnet was made out of a ceramic ferrite compound for the hardest listening sessions. I never had problems with the voice coil, too. At last, a well made product

Koss has some nice humour.
https://www.facebook.com/Koss/photos/a.10152156341692237.1073741829.57608832236/10152181016112237/?type=1
Magnets are cool for more.

Koss made from that picture only two driver elements with some variations for different products. Only the 600 Ohm pro4aa driver is missing.
https://www.facebook.com/Koss/photos/pb.57608832236.-2207520000.1435015775./10152240692862237/?type=3&src=https%3A%2F%2Fscontent-lhr3-1.xx.fbcdn.net%2Fhphotos-xfp1%2Fv%2Ft1.0-9%2F1897864_10152240692862237_4801131708748635668_n.jpg%3Foh%3D4a86178f15a650d6debe93ba194b58fe%26oe%3D55E9451F&size=960%2C672&fbid=10152240692862237
Big drivers for maximum perspective. Great job Koss and the high end Listener want these qualities back, Mr Koss.