Just chiming in to let y'all know I'm still really diggin' the Zaerix tube.. particularly with the HD600. What a terrific match.
I've got plenty of hours on it at this point & its mellowed out quite nicely.. while remaining very resolving. After 75-100 hours, the treble smoothed out to just the right degree. The midbass has a taut lift that's simply perfect for my tastes. This is a critical area as the HD600's native tuning has a slight boost in the same (midbass) region.. so any excessive boost can throw the HD600's balance off. The Zaerix' midbass boost actually accentuates and enhances the HD600's midbass lift. It gives the low end a soft 'bounce' that jives exceedingly well with hip hop, jazz, and soul. The Zaerix' midrange is thoroughly immersive. Clean, liquid, and dynamic.. possessing a slightly dry tone.. but positively oozes a lively, spacious presentation. Again, this synergizes well with the HD600's tonal qualities.
I might spring for the Gold Lion tube too since I'm interested in hearing it.. and some impressions might be useful for the Tube rolling thread.
I'd like to get the Boulder Cable Company mods for the TD-11, too.. anyone else have this done?