I am selling off my headphones
I have 2 pairs of Sennheiser hd600 with hd650 cables:
hd600 with hd650 cable ~ $260

- the hd600 is my absolute favorite headphone. To me, it is unmatched in musicality and really offers a clear window in to the depth of the music
General Description
The HD 600 is an audiophile-grade open dynamic hi-fi/professional stereo headphone. The advanced diaphragm design eliminates standing waves resulting in a clean sound free of artifacts and acoustical disturbances. The HD 600 is a fantastic addition to a hi-fi stack or dedicated listening room, and is a favorite among mastering engineers worldwide.
What the experts are saying:
"I have used my HD 600's for casual and critical listening ever since I got my pair. I can depend on the HD 600 in many different environments and can always expect great results out of it." -Kazuri Arai, Recording/Mix Engineer
Features
High-quality open metal mesh grilles deliver extremely transparent sound
Computer optimized magnet systems minimize harmonic and intermodulation distortion
Extremely lightweight aluminum voice coils ensure excellent transient response
Neodymium ferrous magnet systems ensure optimum sensitivity and an excellent dynamic response
Exceptionally natural, spatial and accurate sound
Detachable, Kevlar reinforced, OFC copper cable
Technical Data
Cable length 10 ft. (3 m)
Ear coupling Around-the-ear
Frequency response (headphones) 12 - 39,000 Hz
Jack plug 1/8
Nominal impedance 300 Ù
Sound pressure level (SPL) 97 dB (SPL), at 1 mW
Total harmonic distortion (THD) 0.1 %
Transducer principle Open-Aire, dynamic
I also have a like new pair of dt880 600Ω ~ $230
The 600Ω high-end audiophile version

FEATURES
• Semi-open back design
• Rugged headband construction
• Single-sided cable
• Soft headband pad
• Excellent sound location
• Gold-plated 1/8" mini stereo jack plug (3.5 mm)
and 1/4" adapter (6.35 mm)
DESCRIPTION
The DT 880 combines the strengths of open and closed studio
headphones. The improved systems of the legendary DT 880 now
offer a high quality headphone with excellent analytical properties,
especially for classical music. The DT 880 reproduces an amazing
sound spectrum, with clean, clear detail from the deepest bass to
the highest highs. The highs are crystal-clear without being
unpleasant, impressive even at low levels. The neutral balanced
mids are analytical and strong, without being predominant. The
DT 880’s bass is voluminous without being too obtrusive. The
single-sided cable, the soft ear pads and the padded headband
make the DT 880 extra-comfortable for extended listening sessions.
The DT 880 is still manufactured in Germany, providing an excellent
quality.
VERSIONS
DT 880 32 Ω, for portable players . . . . . . . Order # 483.931
DT 880 250 Ω, for home hi-fi systems . . . . Order # 481.793
DT 880 600 Ω, for high end systems . . . . . Order # 491.322
TECHNICAL SPECIFICATIONS
Transducer type . . . . . . . . . . . . . . . . Dynamic
Operating principle. . . . . . . . . . . . . . Semi-open
Frequency response . . . . . . . . . . . . . 5 - 35,000 Hz
Nominal impedance . . . . . . . . . . . . . 32 Ω / 250 Ω / 600 Ω
Nominal SPL . . . . . . . . . . . . . . . . . . 96 dB
T.H.D. . . . . . . . . . . . . . . . . . . . . . . . < 0.2%
Power handling capacity. . . . . . . . . . 100 mW
Sound coupling to the ear . . . . . . . . Circumaural
Nominal headband pressure. . . . . . . approx. 2.8 N
Cable length and type . . . . . . . . . . . 3 m / straight cable
Connection . . . . . . . . . . . . . . . . . . . Gold-plated 1/8" mini stereo
jack plug (3.5 mm)
and 1/4" adapter (6.35 mm)
The 600ohm is a substantial improvement over the other versions it uses a lighter driver and is better through the entire frequency spectrum. The dt880 has clearer highs than the hd600 and is musical enough to not leave me feeling cold. I am still partial to the hd600 but the dt880 is excellent. This pair has about 120 hours on them and look beautiful. It is also the most comfortable headphone I have tried.
Thanks

Sam -