Looks like from the Raven web pages and manual , each of the three versions run 12AT7 & 12AU7 preamp tubes so in that regard NOS is not an option solely for Osprey. The power tubes are 6L6GC which again one would expect the same NOS tubes, if desired ,would be an option in all 3; that is unless the Osprey requires the 7518A variant of the 6L6GC . The Osprey comes with the 7518A variant. The Osprey is autobias, the others are self bias