Koss K/7 (1975)
A rare on-ear dynamic stereophone from Koss, built for studio and live monitoring in the mid-1970s
Overview
The Koss K/7 is a dynamic stereo headphone model released in 1975, marketed under various similar names including "Koss K-7" and "Koss K/7 K7 Dynamic Stereophone." Designed for professional use, it was suited for DJ, live monitoring, and studio monitoring applications. These headphones feature an on-ear design with a double housing structure and were originally offered in beige. Though not widely documented, surviving units are labeled as rare vintage items and have appeared in mint condition with original packaging.
Specifications
| Frequency Response | 10Hz - 18,000Hz |
| Impedance | 100 ohms at 1kHz |
| Weight | 425gms |
| Total Harmonic Distortion | less than 1% at 1kHz, 100dB-SPL |
| Driver type | Moving coil stereo headphones |
| Color | beige |
| Model / part number | model K7, P/N 13-3714, F/N 74 |
| Suitable for | DJ, Live Monitoring, Studio Monitoring |
Design
The Koss K/7 uses an on-ear design with a double housing configuration, suggesting a focus on isolation and structural rigidity for monitoring use.
Context
Introduced in 1975, the Koss K/7 belongs to a generation of professional-grade headphones designed for durability and accurate audio reproduction in live and studio environments.
Market
Listings from 2025 show Koss K/7 units selling for $40.00 on Mercari, $88 on Facebook Marketplace (Citrus Heights, CA), and C$41.51 on picclick.ca, with one described as fully working and in mint condition with original box.
eBay Listings
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