You can find out about tube complement, some specs, and pics at:
http://www.sundial.net/~rogerr/tuners.htm#mr71
I talked to McIntosh technical support a couple of weeks who report that the MR-71 is without question the best sounding of all its tuners. But you have to have a good signal or a lesser audio section tuner (including most MDs) but a better RF section tuner will sound better. And sound is subjective, but once you immerse in the 3D sonic landscape of an excellent, updated with NOS hi-end tubes tube tuner you will find it hard to go back to the relatively flat sonic landscape painted by solid state tuners. The best solid state tuners I have heard with this tube sound (actually it is tubes short comings, harmonic distortion that help to create, in part, the effect of harmonic layering that is so palapable) include Naim NAT-01, Accuphase T-101, T-100, T-109 and to a degree the Roksan Caspian and Meridian 504/604.
http://www.sundial.net/~rogerr/tuners.htm#mr71
I talked to McIntosh technical support a couple of weeks who report that the MR-71 is without question the best sounding of all its tuners. But you have to have a good signal or a lesser audio section tuner (including most MDs) but a better RF section tuner will sound better. And sound is subjective, but once you immerse in the 3D sonic landscape of an excellent, updated with NOS hi-end tubes tube tuner you will find it hard to go back to the relatively flat sonic landscape painted by solid state tuners. The best solid state tuners I have heard with this tube sound (actually it is tubes short comings, harmonic distortion that help to create, in part, the effect of harmonic layering that is so palapable) include Naim NAT-01, Accuphase T-101, T-100, T-109 and to a degree the Roksan Caspian and Meridian 504/604.