From: eacj@theory.TC.Cornell.EDU (Julian Vrieslander)
Subject: Sony CDP-X339ES CD player: might be a good base for "poogery"
Organization: Cornell Theory Center
Date: Thu, 30 Jul 1992 03:05:57 GMT

I've obtained some worthwhile improvements to the sound of my Philips CD-680
CD player, by installing some of the usual parts upgrades (better op amps
and capacitors).  Now I am thinking about donating this unit to my parents,
and replacing it with a player using one of the newer convertor technologies.

One product that seems attractive is the new Sony CDP-X339ES.  This unit has
been reviewed in a couple of magazines, with superb bench results and 
favorable subjective ratings.  The build quality, user interface, and styling
are clearly superior to my Philips.

Inside, I found a rugged looking transport and a single fairly beefy
transformer.  There are three compartments, separated by shielding walls, for
the transport, display/control, and digital filter/DAC/analog output 
sub-assemblies.  The filter/DAC/analog circuitry resides on a large
symmetrical PCB, with a copper fence (ground bus) running down the center of
the board.  The PCB has analog ICs on its top side, and the DAC and digital
filter chips (surface mount packages) soldered to the bottom side.  With a
multilayer PCB, this arrangement might improve the isolation of digital
noise from the analog signals.  Unlike my Philips, the analog board in the
Sony has decent separation between parts, and is easily accessible.  If I
felt the urge to do some parts tweaking, it would be quite easy.

Some of the parts appear to be standard consumer grade: JRC 5532 op-amps are
used for the outputs, and 7812/7912 regulators are used for the analog 
supplies (separate IC regulators are used for the transport/control board).
There are generously sized electrolytics for the power supplies, and the
output coupling caps are bypassed with film caps.  There are quite a few
Roederstein film caps, apparently used as local bypasses.

Perhaps someone can help me identify a couple of the other chips.  There are
some JRC 4556D (or maybe they are 45560) chips in 8-pin DIP packages, and
some other 8-pin DIPs marked as 5238 with a tiny logo that looks like
Mitsubishi's.  I cannot find these part numbers in any of my cross-reference
lists.  And does anyone know who makes the electrolytics in brown wrap, with
AVF and AWF markings?

I have the CDP-X339ES home for audition now, and the sound quality of the
stock unit compares well with my modified Philips.  The Sony puts up a 
somewhat deeper image, and sounds a bit smoother and laid back in the highs.
The Philips shows more control in the bass, and has slightly more emphasis
of high frequency details.  If I keep the Sony, I would find it hard to
resist yanking those 5532's for some new op amps (I am using OPA2604's in
the Philips, but I might also try the AD827's that a lot of folks are raving
about).

I would enjoy sharing ideas with anyone else who has tried modifications to
Sony players.  I am also willing to provide more info on the CDP-X339ES,
if anyone is interested.
-- 
Julian Vrieslander 
Neurobiology & Behavior, Mudd Hall, Cornell University, Ithaca NY 14853    
INTERNET: eacj@theory.tc.cornell.edu     BITNET: eacj@crnlthry
UUCP: ..cornell!batcomputer!eacj