[Ebonyks]

I was digging around the basement a while ago, and i managed to come across a pair of old Koss pro/4AA's. I asked my dad about them, and he said they were his pair from the 70's. I went down 5 minutes to koss world headquarters (I'm a lucky person, ay?), and they fixed them up, and replaced the terrible metal grills on them with some nice foam ones.

Can anyone give me some info on these? I hooked them up to my dad's reciever, and they sounded ok, but i couldn't seem to get a good seal on them. I'd think that they could sound better than my sporta pro's (Which are screwing up again, i'm on my second pair, and the left channel keeps dying. Koss is nice about it though)

Do these cans need an amp? Is there anyway to make them lighter? any reccomendations on getting a good seal with them?

Thanks in advance.

 

[mkmelt]

I know of no way to make these headphones lighter. Koss still sells a version of the Pro/4AA headphone. The current model is somewhat lighter than the original version, but still considerably heavier than most other headphones. Wearing these headphones will definitely build up your neck muscles.

The Pro/4AA would probably benefit from a headphone amp, or the headphone output of a receiver. Today's portables or even a PC sound card are not up to driving these headphones to their full potential.

The people as Koss should be able to sell you replacement cushions for these headphones. The ear cushions of the Pro 4/AA were liquid filled, to provide good seal and sound isolation. Over time the liquid dries out, and the cushions cannot be comfortable or properly seal against your ear.

I recall the sound of the Pro/4AA as sounding very smooth, if a bit laid back. The bass was some of the best available at the time, due to the sealed nature of the design. There are any number of headphones available today that are superior to the Pro 4/AA. That does not mean that they don't have a following, especially among those who have owned them for many years and are used to the sound of this sealed design.

Used Koss Pro/4AA headphones show up frequently on eBay, and are not too pricey, so you should have no trouble buying a second pair to use for parts if you need to replace the driver on your phones.

 

[Ebonyks]

I've got the cusions replaced on them, they are no longer liquid filled, but instead, just bulky rubber. (for free too, gotta love them)

I realize that they're no where near the best, and i plan to replace them with some HP-2's as soon as i can track down a pair (dealing with others now) for my melos. Just wondering if it's worth harassing koss to replace another set of sporta pro's (the left channel has died on my second set of them)

 

[mkmelt]

If I was still living in Milwaukee, as I was in 1993 and 1994, I would be back at the Koss factory in a flash. I always found the people at Koss easy to deal with and they do stand behind their products.

I remember visiting the Koss factory showroom and outlet store in Deerfield (I believe it was ) on more than one occassion and scoring some HD/6 powered speakers for my computer for about $50 when these were selling retail for twice the price. You should be able to pick up some good buys on some discontinued headphones or factory seconds.

I also recall listening to a very fine sounding pair of Koss ESP-900 (I think) electrostatic headphones that were being offered for $500 on close out when the retail price was closer to $1000.

Although not generally recognized by the headphone elite for offering the best headphones, believe it or not the management at Koss is, or at least at one time in the not too distant past was, dedicated to quality sound. As I recall, Koss even had a small catalog of their own label of classical CDs that you could buy, that were especially well recorded and mixed for headphone listening.
Like so many other all too few and infrequent attempts by big corporations to make a stand for quality, sadly this too may have past into the mists of time.

Incidentally, about a year after I bought my HD/6 computer speakers the power supply died. I called the people at Koss and they sent me a replacement at no charge. Good people, good products. (I still have those HD/6 speakers!) If they really wanted to, I bet that Koss could offer a megabucks headphone that would be the equal of any other dynamic or electrostatic headphones regardless of the ultimate price. Unfortunately, the reality of the competitiveness of the mass market for moderately priced headphones precludes Koss and many other large companys such as Sony and Yamaha from devoting their R&D and manufacturing resources to such a small segment of the headphone market.

Your Pro/4AA were from a time when the market for headphones was much smaller than today, and the original retail price for those headphones of $50 back in 1970 would be the equivalent of something like $400 today. Think of the type of buyer who today will pay extra to own a headphone like the Sennheiser HD-600 or Grado RS-1/RS-2 and you get the idea of the target audience for the Koss Pro/4AA headphones.