Marantz Sm-7
(late 1978 - mid 1981)

Part of the 1st batch of ESOTECs (not yet named as such), the SM-7 was directly derived from the Model 300DC but with better specs here and there, ESOTEC oblige.

The 2 "sub-speaker" sets benefit from the gain pots while the "direct" set circumvents this extra length of wire and solder. The Japanese versions have a back switch selecting the DC or AC coupling of the inputs, a feature found on 2nd generation ESOTEC (Ma-5, Sm-1000 etc).

Available in black (EU) or in gold (US, JP) with an optional wooden case (US & JP). The Sm-7 was replaced by the fairly similar Sm-9 in mid 1981.

March 4, 2005, UPDATE
Thanks to Wilfred for this:
The Sm-7 output transistors are 2SA1109 & 2SC2589 (180V/10A/200Watts) ; in comparison, the original Model 300DC used the 2SB-645 & 2SD-665 (200V/15A/150 Watts)
The 4 buffer Elco's for the 300DC transformer are 10.000uf and they were upped to 15.000uf for the Sm-7.