My good man ehoove, Thank You for the invite to contribute to this thread....
There are way too many vintage tube amps and preamps worthy of collecting, restoring, retro-resto upgrading and enjoying forever. However, that list could fill pages. While I prefer two mono amps for my stereo system, the early stereo era 1958 to 1963 is well deserving of mention. At that time, the serious competition among manufacturers produced intensely good units. I am a huge fan of the first two stereo years, 1958-1959. The early stereo era would be when the following list of stateside made stereo goodies came along:
Arkay SP-6 preamp, a seriously versatile early stereo effort by an obscure kit company.
Bell Carillon 6060 integrated (top shelf 25 wpc); 3D integrated (historically relevant as it was introduced ca.1953).
Dynaco: PAS-2 (later 3 and 3X) preamps; the combo of two stacked PAM-1 mono preamps alongside the DSC-1 stereo controller;
Dynaco: Stereo 70 amp; Stereo 35 amp (considered top shelf stereo EL84 amp by most who hear it). twin Dyna mono amps.
EICO: HF-81 integrated (among the first three stereo integrateds); HF-85 preamp; HF-86, HF-87, HF-89 amps; Eico mono amps very worthy of top shelf mention, especially HF-50, HF-60, HF-35.
Fairchild: 248 stereo pre (two stacked 245 preamps alongside their super rare stereo controller); Fairchild mono amps are all top shelf, if you can find them.
Fisher: 400C preamp; PR-66 phono stage; SA-100 amp (perhaps the finest stereo EL84 amp?); SA-300 amp; 400CX preamp; The 101 or X-101 int. amp. Twin Fisher mono amps worthy of mention here are the 50 series and 20A.
Gott: also labeled "Bigg of California" P3D stereo preamp, which "copied" the McIntosh C-8 switchable phono EQ.
Harmon Kardon: Citation 1 pre; Citation II amp (top shelf); Citation IV pre; Citation V amp.
Lafayette: KT-600 preamp; KT-550 amp; KT-310 amp (top shelf kits or factory assembled).
Madison Fielding: 320 int. amp; 340 preamp; 360 int. amp. (Mad.-Fldg. use top notch Todd Electric opt iron as found in early Fisher and all 1950s Fairchild).
Marantz: 7C pre; all Marantz amps...
McIntosh: C-20; C-22; C-11 preamps; all Mac amps...
Pilot: 210, 215 and 216 preamps; 232 and 260 amps.
Sargent Rayment: stereo preamp and amps; twin mono amps if u r lucky to find two.
Scott (HH Scott): LK-150 amp (top shelf); LC-21 pre.; most Scott integrateds.
Sherwood: S-5000 int. amp. (highly regarded by many); more of their amps...
This list is anything but complete. It's just the beginning of a "worthy contender" list from the early stereo era. I will certainly edit and add more thread lists and comments...