Koss HV/1LC restoration

I've procrastinated again...because my A/B testing between the Pro 60s and the HV/1LCs is inconclusive.

The two headphones sound considerably different. The HV/1LCs have greater clarity, accuracy, and high end frequency response. Their bass is tighter, and more clean. By contrast, the Pro 60s seem bass heavy.

I'm tempted to say the HV/1LC is the over-all winner, however, the Pro 60s have two redeeming qualities that make the decision difficult.

1) Wearing comfort. The light weight, and loose fit of the Pro 60s is very nice. The velour ear pads are awesome compared to the 'scritchiness' of bare foam.

2) A spatial, open quality to the sound of the Pro 60s. While the HV/1LCs have superior music reproduction, the sound seems to originate in my head. The Pro 60 sound seems to originate in a sphere surrounding my head. The HV/1LCs seem rather claustrophobic by contrast.
 
Any idea how to disassemble the plastic parts that keep adjuster tension? Mine are very loose and won't stay adjusted, and I'm wondering what's in there that I can fix. They don't pop apart readily, and I'm worried about breaking something.

Charles.
 
I have an original HV1 I bought in the early 70's and after several years of ownership they replaced the cord for me at no charge.
 
So, I ended up with a Koss HV/1 with a bad driver, and an HV/1A with a bad driver. Some differences of note:

The HV/1 has black plastic, and a shiny chrome ring between the ear cup halves. The head size adjusters are glued together. The drivers are bolted together, and have posts to which wires are clipped. The driver magnet is flat. The cups can be removed from the metal band without disassembly - the fingers just pull right out of the sides of the ear cups. There are metal tabs to keep the ear cups from rotating too far. There are strain relief tabs molded into the ear cups for the wires that go through the band.

The HV/1A has a slightly brown colored plastic and cord, and a matte silver ring between the ear cup halves. The head size adjusters are riveted together with two rivets. The drivers are melted together. They're inserted over plastic posts, and then a hot tool melts the post and the driver frame together. The driver magnet protrudes into the rounded area you can see on the ear cup side, with the mylar cone over top of it of course. (The HV/1 driver magnet is flat, and the rounded area is largely empty, just a little mylar bubble there). The cups cannot be removed from the band without disassembly -- there are metal retainers on the fingers that keep them from being pulled out of the drivers. There are plastic tabs to keep the ear pieces from rotating too far. The ear pieces on the HV/1A can rotate 90 degrees so that the headphones can lie relatively flat. (This can't be done with the HV/1s). There is no plastic strain relief molded into the ear cups. Oh and the drivers don't have posts, they've got standard solder pads.

Sound-wise, I cannot tell any difference between the HV/1 and HV/1A drivers. I had a bad driver in each, so I combined them into one good headphone, and with a mono source both sides sound identical. So that's nice. The drivers in both of these suffer from the mylar cone coming apart from the driver itself. There is a sealing ring, and the glue just dries out. This will give you a buzz or a lack of highs. Be careful when disassembling, as the mylar and voice coil will tend to stick in the ear cup, and the magnet back will fall right off, breaking the voice coil wires. I could have repaired the one if that hadn't happened to me. The HV/1A drivers cannot be repaired without a lot of work and care. You'll need a hobby saw to cut them apart, and then you'll need to drill and tap for screws to reassemble it. (or just use glue, but it would be nice to leave these as repairable in the future).

Neither of the HV headphones I own have volume potentiometers. I'm not sure if that was an option for a different year, a different model, or for the International market.

Either one of these are good headphones. The HV/1s have more strain relief and more shiny parts. The drivers are more easily repaired. The HV/1As can lie flat, and have head-adjusters that you can disassemble and repair and re-rivet. (In both cases, the HV/1s have broken plastic tabs in the head adjusters, making them loose and floppy. This can be repaired with a strong closed-cell foam, like a piece of a Mr. Clean magic eraser, glued into the inside of the adjuster to make it have some tension). In all cases, every bit of cloth and foam inside these headphones was rotted away, and needed to be replaced.

These look great with blue and red scrim cloth -- I just used speaker grill cloth, and a little contact adhesive, then some foam behind the cloth.

IMG_2935.JPG IMG_2936.JPG

Charles.
 
I had a pair I bought brand new. They did not have the volume controls though. I even thought ahead and bought new foam ear cushions. I finely sold them to buy a pair of Koss pro 4X's. Boy was I disappointed. Whithin a few days the ear cushions became stiff and a connecting wire broke of the driver coil.
 
They do.

But the HV/1-LC probably predates that warranty.
I thought my HV1Lc's had a lifetime waranty. I remember sending them in several times up into the mid 1980's for free repair and I bought my original pair as soon as they came out in the late 70's. I'm now told by Koss there are no repair parts or repair service for them except ear cushions for $5.
 
I thought my HV1Lc's had a lifetime waranty. I remember sending them in several times up into the mid 1980's for free repair and I bought my original pair as soon as they came out in the late 70's. I'm now told by Koss there are no repair parts or repair service for them except ear cushions for $5.
ericj what do you mean they predate that warranty? If they had a lifetime warranty I'm still alive and I still own them!!
 
Hiya.New here.I.m wondering how to get to the drivers of the Pro-60s to replace the cords on them.Thanks.

Welcome to AK, marty34 !

I'm flattered that my Koss thread was your point of entry to the AK community.

I replaced the cord on my original pair of Pro 60s...but that was about 27 years ago that I did it...and I really don't remember the specifics.

IIRC...you have to remove the ear cushions, then you'll see plastic tabs that hold the two halves of the ear 'cups' together. Working from the cushion side (with the cushions removed), pry the tabs a little. The inner half will pop loose, and the driver will be exposed, as will the cord connections.

You'll have to solder a new cord on. The old style Pro-60 has the cord going to the left ear cup only. The newer style has a cord going to each ear piece, and the cords meet in a 'V' under the user's neck. I don't much care for the V-neck style.
 
I've done some extended listening to my HV/1LC recently.

I still appreciate the sound quality, however, the replacement ear cushions compress too much. The hard plastic driver 'grills' end up smashed to my ears, and it becomes uncomfortable after about 15 - 20 minutes.

I had to switch to using my Pro 60s with the velour pads. The Pro 60s win the comfort award.
 
Welcome to AK, marty34 !

I'm flattered that my Koss thread was your point of entry to the AK community.

I replaced the cord on my original pair of Pro 60s...but that was about 27 years ago that I did it...and I really don't remember the specifics.

IIRC...you have to remove the ear cushions, then you'll see plastic tabs that hold the two halves of the ear 'cups' together. Working from the cushion side (with the cushions removed), pry the tabs a little. The inner half will pop loose, and the driver will be exposed, as will the cord connections.

You'll have to solder a new cord on. The old style Pro-60 has the cord going to the left ear cup only. The newer style has a cord going to each ear piece, and the cords meet in a 'V' under the user's neck. I don't much care for the V-neck style.
Many thanks.I souldn't have cut the 6.5mm plug off to try and replace it with a 3.5mm plug.Seems as though,the wire doesn't conduct readily,if that makes sense,a problem I thought happens these days with irrepairable headphone leads.Conductivity of the lead may only be achieved by soldering.I have always liked the sound of these pro60s.Probably,best I have heard.
 
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Welcome to AK, marty34 !

I'm flattered that my Koss thread was your point of entry to the AK community.

I replaced the cord on my original pair of Pro 60s...but that was about 27 years ago that I did it...and I really don't remember the specifics.

IIRC...you have to remove the ear cushions, then you'll see plastic tabs that hold the two halves of the ear 'cups' together. Working from the cushion side (with the cushions removed), pry the tabs a little. The inner half will pop loose, and the driver will be exposed, as will the cord connections.

You'll have to solder a new cord on. The old style Pro-60 has the cord going to the left ear cup only. The newer style has a cord going to each ear piece, and the cords meet in a 'V' under the user's neck. I don't much care for the V-neck style.
The Pro 60s are from 1984.Koss wasnt much help!
 
I'd use a 3.5 female inline jack.

Hard mount it with hot glue on the outside of the left ear cup.

Then get a cord with 3.5 mm male plugs on each end.
 
I'd use a 3.5 female inline jack.

Hard mount it with hot glue on the outside of the left ear cup.

Then get a cord with 3.5 mm male plugs on each end.

Thanks.Wired up a 3.5mm plug to the reusable original lead (luckily).The drivers themselves seem to be in a sealed enclosure on these.Put the new Koss HV/X ear cushions on.Sounds great as always.
 
Thanks.Wired up a 3.5mm plug to the reusable original lead (luckily).The drivers themselves seem to be in a sealed enclosure on these.Put the new Koss HV/X ear cushions on.Sounds great as always.[/Q

Glad this Koss thread is here.AudioKarma helped get these up and running again.The koss company themselves not so great.It may be worth mentioning,that the ear cushion 'Nitto/Nikko?' adhesive tape has a life of its own.When you finally get the tape covers off,It is better to take one side off at a time and stick it down to the headphone bodies first.The Black tape goes into a Pretzel shape if not restrained by taking both sides of backing off.
.Also,the headphone wire has a clear insulation on it.Not readily apparent at first.Once removed,it was ok to solder and get good conductivity again.Try doing that on Human hair thickness wiring on modern Philips headphones made in China ! I also left the original 'plates' off that the original foam was glued to(?).The plates were damaged on removal (to see if there were any screws underneath) sonically,it probably wouldnt make much difference anyway.
Probably to make the foam last longer I might put some 'hygenic' or cloth covers on (from ebay,etc).I also put these on other headphones I have that have pleather ear cushions.Does help stop the ears sweating.
 
Wow. That was over 8 months ago.

I simply called the customer support phone number on the Koss Website, a nice woman answered, and stated she could sell me the earpads for, IIRC, $4.40 a pair.

I said, "Really? How much for shipping? She said that included shipping.

5 days later, they arrived for less than $5.00. They seem a little thicker than the originals, and they're not as comfy as the velours, but the price and fit are perfect.

View attachment 545426View attachment 545427

Project done!
I did this exact same thing about 2 years ago .
 
I did this exact same thing about 2 years ago .
Awe Man.

I pulled my HV1/LC out of 'storage'. Actually they had been laying flat on top an ADS L520 speaker with the 'new' ear cups on the wood veneer for about 2 years.

The foam stuck to the veneer. One of the cups has started to deteriorate. They're only 4 years old.

Bummer.

My new HD6xx Sennheiser cans blow the old Koss cans out of the water.

I'm not sure I want to order another pair of ear cups from Koss, just to continue having a 'dwarf experience'. A paid a C note for the HV1/LCs , about half the price of the HD 6xx.

I'll try to find a better ear cup for the HV1/LC. I searched long and hard four years. Guess i need to look some more.
 
I just signed up for membership on AUDIOKARMA today. Hopefully someone is still following this feed. I've had the link saved for a couple of years, waiting to dig into a rebuild of my HV/1's. I've had them since 1985. They were my late uncle's before that. I have foam ear pads from Koss (I ordered them from Koss once many years ago and again a couple years back in anticipation of this project). This time, I wanted to replace the deteriorated white cloth (scrim cloth I understand). I thought it would be an easy "Covid project" But it has proven to be frustrating

I have scrim cloth fabric but getting the screws out proved a challenge. After ordering 4mm thinwall hex socket drivers that didn't work and checking with some electronic repair shops I opted to use a Dremel cutting tool to cut a grove across the head. Success! But only to find the scrim cloth is locked inside the driver assembly with plastic rivets. I need micro self-tapping screws to close it up again. After a trip into the City (Vancouver) to get some from Lee's Electronics I now have the setback of the human-hair like wires from the copper winding to the + & - pins have broken. So, at this point I'm reaching out here to see if there is anything anyone can suggest for an easy fix. They are probably going to snap on the other driver assembly too when I open it. Grrrr! I want to save these headphones. They worked perfectly other than the deteriorating foam ear pads. I guess I should have left them alone.

Can anyone help with a solution? I'm going to take the drivers back to the speaker repair shop I visited before (to ask about a 4mm tool). If they can't repair them, or I can't get a solution here, then I guess they'll have to go for parts on Ebay. I would really be sad to see that be necessary. Can anyone help me out?
 
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