Sony's first consumer d/a converter and companion of the CDP-552ESD integrated player.
Strangely, though, Sony didn't use its own d/a ICs nor Philips' but Burr Brown's... the same as in the CDP-552ESD.
The 702ES has two Burr-Brown PCM-53JP d/a chips teamed with Sony CXD-23034 digital filters, CX-23053 C-Mos LSI for demod' + sync, 7th-order Butterworth GIC-type LPF and special output op-amps which really are PNP/NPN high-fT pairs with MHz bandwidth.
Hardware-wise, this is all typical 1980s Sony : copper bus bars and heat sinking, LC-OFC wiring (99,995% purity), a total of 33,000µF of ELNA for Audio, ELNA Cerafine and metal film caps and one bigga 190V toroidal trafo.
The chassis, although not yet copper-plated, is made of 3mm / 4mm aluminium slabs (top & sides, respectively) plus 10mm & 15mm aluminium structuring corners ; all non-magnetic.
Two digital inputs and two outputs are provided, alongwith one fixed and one variable analogue outputs, plus a quality headphone amp.
As noted by many, the amazing sound quality results not so much from the technologies used but by the care and absolute perfection in build-quality and choice of components.
That's very Sony, be it in the pre-Esprit, ESPRIT or R series : we're in this for the music, not the technical tour-de-force or outer-space specifications : like a TA-E88B, a TA-N902 or a TA-ER1, the 702ES makes
m u s i c.
The 702ES gave way to the much upgraded DAS-703ES, the DAS-R1 masterpiece, the DAS-R1a über-masterpiece and the DAS-R10 best-ever-masterpiece.
A real 702ES here.