Pwr tubes for 300B and 805 series (of Cary) will only half life that normal condition. Tubes biased at 2 times higher than normal condition. That's why they have big power output compare to same model amps from another factory.
I compared : Cary 300B SEI (1,5 years old) sounds bass shy and have smaller soundstage when compare to Opera Audio/Consonance Ref 5.0 (20 hours burn in only since new).
Of course new Ref 5.0 still lose on musicality , noise floor , depth. Ref 5.0 still need more burn in (at least 200 hours). Anyway 5.0 is much more cheaper.
My 2 cents.
Riwin
I compared : Cary 300B SEI (1,5 years old) sounds bass shy and have smaller soundstage when compare to Opera Audio/Consonance Ref 5.0 (20 hours burn in only since new).
Of course new Ref 5.0 still lose on musicality , noise floor , depth. Ref 5.0 still need more burn in (at least 200 hours). Anyway 5.0 is much more cheaper.
My 2 cents.
Riwin