Just a word of caution, but it appears as if Hsu is having significant issues with the STF-2 on driver seals as well as amplifier gain settings. I had one for a few hours from CompUSA, found out that mine was afflicted with the dreaded "Darla" disease,(named after the scene in Finding Nemo that reveals the flaw) and returned it for credit,since I wasn't sure if the replacement, when available at my local CompUSA, would have the same symptoms. I bought an EP175, and so far it is fine with my m50's, Vp100 & Qs4's...
b.
