Koss K/6A (aka Realistic Pro 20)- Overview
Not to be confused with the K/6, also known as the Realistic Custom Pro by Radio Shack which was introduced in 1972, the K/6A is the second generation of the K/6 series introduced in the late 70's. The K/6A is also known as the Realistic Pro 20 sold by Radio Shack. By today's standards the K/6A ranks low amongst headphone enthusiasts. The sound quality suffers but the overall build quality and comfort level is decent.
General Description of the Sound
The K/6A is known to many as an inaccurate and poor sounding pair of headphones. Weak in the high frequencies causing them to miss a lot of fine detail in music, extremely bright colored midrange that makes vocals sound like they're being sent over a telephone, and very boxy bass sounding like the bass from a cheap boombox. I've found that if you use a graphic equalizer with them and turn down the 3khz to about -4db, this will help smooth out the shrilly telephony mids.
Trance88 23:37, 12 February 2009 (EST)
Pricing & Other Data of Interest
Originally valued around $25 in 1979. Today, depending on condition and who's selling them, the K/6A can go for just about anything between $2 and $30 USD.
Headphones Technology: 2.5" low angle dynamic paper cone drivers.
Frequency Response: 20 - 16,000 hz