Koss Pro/4AA headphones... wow

nadams

I just recently aquired a pair of vintage 1972 Koss Pro/4AA headphones. I am so intensely surprised by the sound these things put out! They put my 2ch system to shame! The isolation from outside noise is especially useful in my bedroom, as I have a number of computers that all have multiple fans for cooling, which makes my room bad for sound, overall.

These things are HEAVY.... I'm already feeling a little off balance and I've only been listening to them for about an hour. I'm feeling the tinges of a headache, but I think that's from the music and the late hour. Minor problems with these 'phones include missing foam from over the drivers, and the earcups have deflated (they are air-filled). Major problem is that there's a short in the cord somewhere that makes the left channel cut out if I am sitting the wrong way.... very annoying.

The cool thing about the headphones I have, in particular, is that I have all the original receipts and literature for these from the 70s.

And now, imagine my surprise that when I go to research these 'phones a little bit more, I find that they are still being sold on amazon.com for $60! Go figure! They've stood the test of over 30 years.... Amazing.

I'm really enjoying them... And thinking about getting a new pair to aleviate the problems I have with the current pair.

nadams

Billm57

They are still selling them new. I didnt liek how expensive they were going for on Ebay for originals so i bought a pair new from J & R.. I had apair of them all through highscholl an dyes they are heavy but man do they isolate outside noise

Billm57

also..the orignal ones were fluid filled earpieces

Tour2ma

Yup, great old headphone. My originals deflated and were resoldered many times. Nabbed a choice pair on ebay for $27 a few months ago.

Billm,
Are the new ones as good as the old?

nadams

Tour-
How do the headphones come apart? I want to fix this wire, but the short is in the left 'phone itself, and I need to get in there somehow. Direction? Thanks,

nadams

Tour2ma

na,
You've likely discovered that unscrewing the silver cap on the outside of the left channel's cup gets you nowhere. In two words the secret is "Exacto knife".

You can carefully cut around and under the ear cushion's lip at the silver ring to remove the cushion. Be careful not to puncture the cushioned part, but it's not too hard as there's about a 3/8" lip.

Then cut around the perimieter of the speaker baffle where it's glued to the shell. The baffle should end up free of the shell. The left channel is normally the one where the connection issues are as the unbilicle enters there.

Once in, the repairs needed may or may not be apparent. Often instead of spotting a broken or loose lead, the wire(s) are broken inside the bundle somewhere. Continuity checks with a VOM help ID the culprit (you unscrew the cover on the jack plug to expose the terminations there). Then you start sniping, but only after sketching which color wire terminates where. You may end up having to snip off a couple inches to find good wire, as often the break is right at the entry point to the shell.

Going back is just a glue job. The ear cushion is the tough part, but get a point glued at the 12 o'clock position and then you can work your way around with a little patience.

It's a job, but if your 4AA's are beyond the old "loop the unbilicle over the left shell trick" to keep from having a channel cut out everytime you move your head, it's not like you have anything to lose.

Wish I knew how to restore the cushions. Lesser Koss models had foam fill, but then they were lesser models.

nadams

It's a little strange... the break is not in the main wire that comes into the left headphone. It actually cuts in and out of the wire coming out of the top of the left 'phone (going to the right) gets moved too much. Now, I would think that it would be cutting the right 'phone out, not the left, but what do I know? Maybe it's touching a short somewhere else or something. I don't know if I really want to cut these things up. I guess I'll probably just live with 'em for now.

Oh, and about the mic boom attachement spot.... I also got all the original literature for these 'phones, so I had already read that it was a boom attachement :-).