I have a several Koss headphones and I think these might be my favorites sound wise. Still deciding between them and the KPH40. I put them on a porta pro headband as I prefer that form factor.
TymmyNo, the 75s are titanium coated, I don't think they used that driver in anything else (OK maybe the KTXPro, I'd have to re-check metal571's review). The older ones all have the same non-titanium driver: Porta Pro = Sporta Pro = KPH30i. And then the KPH40 I think is some newer design but still not titanium coated, and possibly only the housing is changed vs. the 30 and not the active parts.