I'm not even sure how to write this...
A decade ago I bought a Senn 600 and HATED it! Was very weary of the 650 but did get one and liked it. Moved to the O2, tried the HiFiMan range, the 800, moved to LCD-2 and now...
Back to the 600 and LOVE it! Its actually annoying me that this relic of a can is so bloody good especially given its price. Was my first one DOA, has Senn used their right to improve the product over time? I don't know. I just know that music sounds quite a bit more "right" through the 600 than it should. No aftermarket cable, just the stock junky cable and its frankly more enjoyable than the LCD-2 with SilverDragon. Would I like bass to extend further? Yes, but the music I listen to really has nearly nothing going on sub 40Hz. So I'm just stuck here, jaw on floor unable to explain why 1) its competing way above its price and 2) why is it not on everyone's short list?
Best I can guess... Amps and DACs have advanced hand over fist since the 600 was released and since we all moved to darker and darker cans that the 600 was forgotten. Which is sad since it's briliant on modern gear. At any rate if my first 600 sounded anything like this one, I wouldn't have 1000+ posts ;)
There was supposedly a driver change at some point. I know that my first HD600 had a treble peak that bordered on sibilance, but my current pair is very smooth. But ironically the newer version of the driver is apparently the brighter one, so my "newer" pair is probably the older version. I bought them both used in mint condition and re-sold the first pair so I never had them side by side to even confirm that the drivers had a different appearance so I'm not sure really, I just know they sounded different.
Edited by grokit - 2/20/12 at 5:13pm