Summary: Understand they are 'studio' headphones, extra connection port, etc. I bought my 1st set WAY back in late 1972/early 1973. While in the service, shipped them 3X across country--they were flawless. The oil-filled pads wore out. Bought the 2nd set from Sam Goody's in NYC after 4+ years.
Summary: To this day I won't settle for any other brand than Koss & these headphones are the reason! I bought mine around 1976 in CA but they, along with my entire music collection were stolen in 1979. Recommend, heck Yeah!!
Pros: This is the ideal, the one against all others are judged
Cons: The price (When I bought mine they were about $30)
Summary: I had these lying around for years never thinking about combining them with my rig. Plugged them in and lo and behold, they are amazing. As a user of apple ear buds for the longest time, these cans help me pick out the weakest signals. I was actually astounded to hear how much I was missing.
Summary: Bought these in 1978. Used them until they were worn out at least 20yrs. had them in a cabinet for years then found out they were guaranteed for life .Sent them back to Koss and they sent me a new set. After 38 yrs they still stand behind their phones and they sound incredible couldn't be happier .
Summary: Bestest headphones ever. I must have had them nearly 40 years and they are as good as new! Once, one of the 'speakers' became loose so I sent them to Koss for repair - they did a full service - everything, new 'speakers', foams and cushions and at a very reasonable cost.
Summary: When I order these, shall be my 4th set since about 1971-72. They have traveled with me through my time in the service, been moved a number of times around the country, in boxes/trunks/car-trunks. Only problems I've had is getting the oil-filled ear-pads replaced.
Pros: Magnificent sound, very full range, massive bass response
Cons: They do weigh a bit more than most may care for.
Summary: I purchased my "AA's" in '72 and use them almost daily. I have gone through several sets of pads but other than that they are still the set I go to when I want to listen to music in a busy room.
Pros: Audio quality, construction
Cons: A little heavy but weight is well distributed
Summary: I used these phones from 1977 till 1987 and beyond. I assume the original owner still has them. They were used to record and mix tracks in our small studio along with some other types. These were the favorites. They isolated you from room noise and they didn't lie.
Pros: Rugged, good sound, neutral, good isolation
Cons: Heavy, sonically flat, can be uncomfortable...
Summary: I had a pair of the Koss PRO 4/AAs and they had stopped working. Not only that, the coiled cord was no longer very coiled and the plastic headband part was coming apart. These were very old friends used for Ham Radio and stereo listening.
Summary: I have owned multiple KOSS Pro 4/AA headphones over the years. The Original high power, high volume, super durable headphones from the 1970s - there is a reason they still make them. The Good: They provide good, solid, clear communications audio.