RFT HOK 80-2
RFT HOK 80-2 - Overview
DDR (East German) made headphones. Not much is know about them. The drivers as well as headphone assembly look to be homegrown and not based on other headphones, although is seems that is was inspired by PMB's developments at the same time.
General Description of the Sound
Pricing & Other Data of Interest
EVP 165,- M
Note that the HOK80 v1 has a different headband. The HOK80 v1 is said to have less bass than v2. There is also a dynamic headphone using the same frame as the HOK 80 v2.
It was made by the VEB Keramische Werke Hermsdorf, in and probably around 1986.
Wiedergabefrequenzbereich 20Hz - 20kHz
Nennwiderstand pro Wandler 60 OHM
Betriebsleistung 5mW bei 94 db
Klirrfaktor kleiner ,gleich 0,5%
Gewicht 0,3 kg
Frequency response: 20Hz - 20kHz
Nominal Impedance (per transducer): 60 Ohm
Sensitivity: 94dB for 5mW input
Maximum continuous power: 2W
THD: 0.5% or less (at 94 dB)
Weight: 300 g
Note that the original pads were missing on my set, so I replaced them with lambskin earpads made of eight layers of lambskin. Not extremely comfortable for longer sessions but brings out the bass. The HOK 80 v2 is originally closed back (almost, it's not properly done), but can be converted to fully open by removing a plastic disc from each cup. I converted my set to open to avoid the mess of reflections inside.
Add the white foam baffle you see through the holes to seal the cup. Add the black 5mm foam that the driver rests on. One layer of "dampy" felt on the driver (the stock felt might be too thick, but try it if you want). Then one layer of thin "dampy" woven fabric. Stock springy foam on top. Remove the disc that makes the cans closed. Fasten the plastic ring using blutak. (and then put some air tight pads on, of course...). Then put some rock music on.
It is necessary to follow the instructions by Ericj on head-fi to take these apart and put them together again without breaking anything. http://www.head-fi.org/forums/3173771-post787.html