I remember dreaming about this machine. I was very young for sure but this was very impressive to look at and to use. Also it had dbx. Also it had more buttons than necessary - for a young teenager... it counts.
The Z-7000 had all of an already bygone era: an unbelievably solid quality : 17,9kg of diecast zinc alloy for the entire frame and drive assembly plus the sides and top quarters covered with wood (!).
Also four motors, three heads, two closed-loop capstans and all of the future, too : the no less than mirific "Computomatic" system allowed to keep all settings in memory and visualize everything on a huge display window as well as search and memorize tracks.
I'm sure the Teac's marketing wizards came up with a better name which was already registered by another brand so they folded back on this - nevertheless a charming 1960s flavor for a 1980s mini computer.
Computomatic deals with almost everything in the 7000 : block-program/replay, one-touch rewind-to-rec-start (STR), STZ and STC memory points, SES (spot erase), in/out faders, Hi-Extend (high-frequency MOL pinching), 2 to 10s rec-mute, auto-monitoring, 10% pitch control. A battery allows to keep in memory the Auto-Cal calibrations made.
Tape guides are made of ceramic and the heads are set in a big diecast fixer. The play head is DC coupled to FET audio stages with regulated bipolar power-supply overall.
Inside is something of a nightmare with a few vertical PCBs and wiring long enough to equate the diameter of Pluto.
Quite frankly, however, it's a fairly ugly beast.
But, sound-wise, you'd get very close to open-reel quality when recording with the dbx on - really.
And the exact same quality would be found on the Z-6000 "mid-end" deck ; the Z-5000, if impressive, was a more conventional machine (with outstanding specs nevertheless) (and built/T-tagged by KEI, not Teac btw...).
I didn't buy a Z-7000, nor a Nakamichi RX-505 but finally settled for a Denon DR-M4 in 1984 and it seems many potential buyers finally settled for some other recorder.
If I judge by the 1984 price sheet, I can understand why : the Z-7000 was even more expensive than Teac's own X-2000R open-reel recorder - CQFD.
Like a few other Teac cassette recorders, the Z-5000 and Z-7000 were T-tagged by KEI and not by Kurume Denshi, Teac's usual supplier - but the former may be related to the latter...