I remember seeing these 'phones back in the Quadraphonic days of the early 70s. I was a BIG Pro4AA fan then, and, knowing Koss' fondness for using the same drivers in several models at a time, I assumed tha the K 2+2 was just a "gussied up" set of Pro4AAs with two drivers in each earcup (it looked STRIKINGLY like the Pro4AA).

Fast forward to today...I have an opportunity to actually buy a vintage pair of K 2+2 'phones. Obviously their Quad capabilities are of little importance. What I want to know is, does anyone here still have a working set, or trust their memory enough to let me know if they actually sounded good (say, in the same league as the Pro4AA)? Also, when in Stereo mode, what happens? Does it turn off the back drivers, or are ALL drivers (front and back) active (which I would greatly prefer...theoretically lower bass distortion should (could) result).

Now don't flame me. I KNOW these aren't the all-time best 'phones. I don't expect them to compete with HD-580s or 600s (my favorites today). But I DO enjoy that classic Koss sound. The fact that so many 20-35 year old Koss cans end up on Ebay is a testament to how well the damn things were built! SO, anybody got any comments on what I could expect sound-quality-wise?

I actually found a set of these in my barn last night, cleaned them up and plugged them into my reciever.
 
Aside from the 2/4 channel switch being nearly dead, they are in great shape and sound awesome, considering how they were stored for the last 30-ish years.

I know it is a little late to reply to this but I still have my 2+2's and the manual, every once in a while I take them out and they sound as good as when I bought them. I had to take the controller apart and clean the contacts and replace the cushions. Koss sent me some a few years ago that I had to cut out and make due but it worked out OK. The music still spins around in my head when I play around with the controls.  

My Dad had them and so I used the headphones for my 'formative' years on his vintage Akai quadraphonic Hi-fi and Reel-to-Reel.  He was stationed in Thailand in 1971, apparently his components were all featured in Playboy as the 'toys' to own.  The quadraphonic effect was quite similar to SACD/DVD-A of a few years ago - you kind of felt like in the middle of the soundstage.  Anyway, I would not put them in the same area of quality as my Grado SR225's but I remember them being of high quality - especially in reproducing bass response.  One caveat, as they got older the buildup of static electricity would be released on occasion - into my ear lobe (not the greatest sensation).  This may have been a result of my abuse of the vintage equipment - I WAS a teenager.  I still have them, but don't use them b/c of the static discharge.  Before they developed the 'quirk' of zapping my ears, they did sound great/good.  Other things to look for - the 2ch/4ch selector switch can break and using them in 4ch mode on a 2ch source can introduce some hum into the music.  In your shoes, I would buy them, but I have a nostalgic feeling for them...

not only remember, I still have and use a pair of the 2+2's.  Had a Teac 3340 4 ch deck, and this was just the thing to be able to review/preview all 4 tracks.
 I'd get 'em, if they're still working.
HS