The Marantz ESOTEC series makes for a complex story filled with mistakes, mishaps and three-way changes of ownership.
As for the Sony ESPRIT, the truth lies in the origins and the ESOTEC origins aren't as "high-end" as marketing wanted us to believe in 1979/1980.
When the series was put under development, owner Superscope was in dire need of cash for various reasons but also because Marantz wasn't selling as well as it did only two or three years before.
Despite its asian manufacturing origins since the late 1960s, Marantz was completely behind its competitors when it came to modern features and functions.
Even design still was very "70s-ish" and heavy-handed at a time Yamaha was making the A-1, Sony the TA-F80 and Kenwood the L-01A.
Out of this, Superscope had two solutions : either design something entirely new and somewhat more "trendy" or... sell the entire operation to somebody with more cash reserves.
Option #2 was retained and Philips bought 43% of all Marantz assets in 1980. However, part of what was to be the ESOTEC series was already on its way, or "re-made", without the ESOTEC tag yet (Sc-7 & Sm-7, 1978).
Two other items also were already "developed" : the Sm 1000 and the Tt 1000.
The Sm 1000 is the culmination of the Model 500 series, as designed by Michael Custer and the last of the Marantz A Line, ie, the one designed and built exclusively in the USA.
The Tt 1000 was a repackaged Micro Seiki design built by Micro on Marantz' specs, produced after the higher-end Tt 700 (1978) and Tt 1800 (1979) prototypes.
These two components however showed where Superscope wanted to go so as to "save" Marantz from drowning at the step of the 1980s : pricey high-end with exclusive build-quality. And, previsibly, limited sales.
It is when the two "1000" were launched that the ESOTEC tag appeared, swiftly retrofitted to the original Sc-7 and Sm-7.
It is also during this timeframe that Marantz, still Superscope-owned, launched its first set of classic reissues, limited to Japan release : Model 7K, Model 8BK and Model 9K - the added "K" stands for kit.
These kits sold extremely poorly : if doing a new-old-new thing like the ESOTEC while reissuing 1950s oldies was coherent, it clearly showed Superscope couldn't cope, at all, with modern times.
As planned and initiated by Superscope, this "new" high-end set was mainly made of 1970s "oldies" repackaged with minor modifications and newer looks : the Sm-7 and Sc-7 respectively were a Model 300DC and a Model 3650.
Also offered in late 1978 was the possibility to have the customer's name silkscreened on the front flap of the Sc-7, Sm-7 and Pm-8, along with a "25th Anniversary" tag ; Marantz was founded in 1953 so 1953 + 25 = 1978.
This, however, was not really effective or not advertised enough as I've only seen one such engraved Sc-7 besides the one made for the Marantz-employed "S. Matsumoto" (there are two Matsumotos at Marantz / D&M today : Juro and Hirozaki).
The next 1979/1980 lineups also relied on older components (St-7, aka Model 2130 or Pm-8, aka Model 1300DC) while other, lower-end, variants were made while Philips was about to actually engulf Marantz : Pm-5, Pm-6, Ma-5, Sc-6, etc, all built in Japan in the Kumamoto factory and/or by any of the regular Superscope OEM suppliers such as S&R or the fully-owned Miyako Audio.
An upper-end and really new design Pm-7 integrated amp was planned and prototyped but not produced.
Once the Philips ownership became effective, the dust of this mayhem briefly settled down - "briefly" because of product planning and old Superscope decisions.
First, the ESOTEC lineup, well fitted to the US market and the Marantz "image" there, didn't do too well in Japan after the initial 1979/1980 impetus - planned stars of the new show, the Tt 1000 and Sm 1000 sold very poorly...
Second, the Marantz/Philips team was sued for copyright infringement for the illegal use of the ESOTEC name which had been filed a few years back by another japanese company.
The case being undefendable, Philips had no other solution than to get rid of the Superscope-chosen name, quickly sell at discount prices what was in stock with the ESOTEC name, redo advertising, redo catalogs with (or even without) a generic "E Series" tag (1982/83) and launch new production batches without the name. Costly.
(see one late production Pm-5 with its "Esotec Series" silkscreening blanked out here)
Other designs fell anywhere within a very hectic and disorganized distribution :
mk2 versions for the japanese Pm-8 or St-8, the two-speed Sd-7, St-5, Pm-4, Sm-8 / Sc-8, the upped Sm-9 / Sc-9 or later Pm-6a.
Also made were in-betweens such as the x-rare Sm-10 which was nothing more than two Ma-5 united by a common frontplate in a chassis originally designed for the Model 15, way back in... 1968. That (pretty) chassis shape was also chosen for the Pm-4 and even for the DA-3, a c. 1987 auto-reverse k7/amp karaoke compact combo built by Miyako Audio !
While actual circuit design was gradually being transfered to Marantz Japan by Philips for what used to be the "B" line, newer high-end products were planned and designed but housed, again, in old chassis. They were also drowned on arrival by truly overblown pricetags : enter the Sc 1000, Mc 1000, Sm 700 and Sm 800, all four mainly made for the japanese market and unmarketed or so little elsewhere.
While the dust was somewhat settling, 1982/83, two components were beautifully designed but very vaguely distributed : SH-A20 and SH-T10. The former is a 208,000¥ integrated amp with a bigga toroidal trafo and Heat-Pipe, the latter a 100,000¥ FM-only tuner. "SH" stands for Sound House, a local distributor with ambitions.
Both are the most beautiful of the entire series (with a magnificent enclosure design shared by the extra-extra-rare japanese versions of the CD-73) and were obviously built to more exacting standards than the regular Esotecs. That "SH" set was complemented by a Micro Seiki turntable (yes : who else ?) but all three sold very poorly.
Later Marantz Japan designs tried to follow this (ex-)ESOTEC route but either didn't sell at all or, as often, only in one market : Sc-11 & Sm-11, Ma-6, Ma-7 and, even later on, the DLT-1 or PH-95.
Although several components actually sold very well (Pm-5, Sm-7, Sc-8 etc), the ESOTEC series came in between major ownership changes from an owner, Superscope, who was actually looking backward and got much too greedy regarding pricetags.
Even a crowned name such as Marantz wasn't enough by 1980 to sell repackaged and OEM'ed components - and the new owner, Philips, not really used to selling high-end audio, didn't change the original Superscope slant.
The ESOTEC series vanished silently, unreplaced by anything equivalent : it was time to move forward.