Hi!
In soviet mostly use Hungary machines (one of them I have at home, soon I buy second machine, and my girlfriend very dissatisfied about this :-) ), this machines - Mechlabor STM-610 (at radio/tv stations also use STM-310 - compact trasportable units, and STM-210 (precedence of 610)).
This heavy (70 kilos) and perfect made machine, here's my, loaded with RadioArts tape:
Sadly this machines had poorly designed amps, but I trow away PCB's and assemble tube amps of my own design.
Mechanics are perfect! with heavy duty die cast chassis, and PAPST motors, also this machines have variable speed FF and switchable tape tension.
Also I perform some modifications of capstan motor, so it can runs at 3.75 ips, so I have 3 speed machine, that have interchangeable headblocks (4 track play; 2 track play; full track play; 2 track record; full track record), on play headblocks only one playback head installed, tape path allows to do it.
Some stations have Studer A80 - best sounding solid state machines I hear.
Older soviet made machines was tubed, example - MEZ-28, it was mono full track an runs at 30 IPS, amp have alot of permalloy transformers, and was very heavy, my frend have some of this amps for parts.
I never seen tubed soviet stereo machine.
In USSR of course was made some stereo solid-state machines, but quality of manufacture was poor, especially on mechanics. So stations prefere to buy STM's.
Hope I answer on you'r question. And sorry for my poor english :-)