Koss KSC75s modded onto a headband, and with quarter-mod on its pads, are freakishly good. IMO more balanced-sounding and with better timbre than most headphones under $400.
Relative to headphones costing under $400 that I've recently auditioned or own, I prefer its sound over Audio Technica M50, Hifiman HE300, AKG Q701, YUIN G2A, Grado Sr60i, in no particular order. The only two headphones under $400 I've heard or own so far that trump these modded KSC75s are LFF's Paradox T50RP, and Hifiman HE400. Even then I really think these are more musical.
The clamping and proper seal induced by the headband does something with the KSC75's sound that is major and accidentally fantastic, bass is suddenly at a perfect level, mids become silky smooth, liquid, and almost perfectly neutral and clean as hell, treble gets tamed 2 notches but still retains a slight zing that makes acoustics and instruments pop. Theoretical headphones with this particular sound but with higher resolution and better extension, and tighter bass with a fuller body, would be perfect...pretty much akin to LCD3's sound.
I find them freakishly good as well. I have mine on the Parts-express headband, and replaced the plastic driver covers with metal mesh. I really like the slightly less clamping force with the Parts-express headband (I tried them on the Portapro headband for about a week). It would be interesting to know how they sound compared to your modded pair (your mod is simpler).
At any rate, yes, they sound awesome. I also have PX100-II's which sound amazing in a completely different way, but I find myself listening to the KSC75's as much if not more. And while I wait to get higher end phones, these two pairs are keeping me happy.
Yeah, I was surprised too. I've had my KSC75s for years now, never realized its true potential until I've actually gone quite a ways through this hobby, auditioning and buying lots of great (and not so great) headphones. The particular headband Ive clicked the KSC75s into at the moment is a Portapro headband that my friend gave to me when his portapro driver broke, it has the identical driver-securing mechanism as the KSC75 clips do. And the quarter mod is just cutting quarter-sized holes I cut out in the foam. Do NOT use other types of pleather pads, they actually offset the balanced nature of the sound a lot; the stock foam is the best.
I really think Koss could use the KSC75 drivers, make em into Grado-style on-ear sealed headband headphones, sell em for $200, and people will dig the sound a lot. Kind of what the "StratoKOSSer" is (on the full-sized headphones forum). The dangling earclip design just kills the potential of these little guys completely, what a shame.
The SstratoKOSSer's are indeed cool! Fwiw, another combo that I really liked was the Portapro drivers on the KSC75's earclips.
Edited by waynes world - 9/3/12 at 11:01am