When Marantz launched the CD-7 is left several people
scratching their heads including hardened Marantz followers. In the light of
fast moving DAC technology and increasing popularity of SACD, the CD-7 was a CD
only spinner with 16-bit DAC’s from circa 1985. The DAC’s though were no
ordinary 16-bit type, Marantz and sister company Philips did a limited run of
the TDA1541A S2 ‘Double Crown’ variety, heralded by many to this day as the
best sounding DAC ever made. Looking at the current prices that these DAC’s
sell for, and if you can find them, and you start to get an idea of what it’s
all about. Marantz also developed a brand new filter for the CD7, the regular
SAA7220 which was married with almost every 1541 based player was replaced with
the MZ777f DSP chipset. This enabled a selectable range of filters including an
advanced ‘FIR’ filter as well as a filter which preserved the sonic character
of the classic SAA7220.
Listen to a CD-7, and it sounds quite different to any of
the current 24 bit, even 32 bit players and DAC’s of today. The CD7 has an
earthy quality, highly musical, dynamic, if a tad dark and heavy footed sounding
for some tastes.
Given the fact that the CD7 has been designed to extract
as much as possible from the TDA1541 chipsets, careful consideration was given
to upgrade modifications. We wanted to preserve the sound of the CD7 but take
its performance beyond the cost restraints and limitations that come with mass
production. Identifying and planning the upgrades took considerable time, and
we started with looking at main power supplies, regulated supplies and master
clock; all areas where if improved will lead to better sound. The master clock
although better than earlier generation players like the CD12 was still basic
in design, a simple inverter arrangement, albeit a single gate with a further
gate to buffer the clock output. Replacing this “Superclock” now version 4, brought
major improvements to several areas of the sound, particularly the players
ability to project a wide open, spacious sound-stage, control in the lower
frequencies, improved stereo separation. Adding a separate Superclock 4 power
supply lifted performance again with further gains in clarity, detail and
focus.
The CD7’s power supplies are typical of Marantz in as
much as the analogue supply gets all the attention but the digital supply is
almost forgotten about. OK, so if you have a budget to spend then the analogue
supply is where to go, but digital supplies also contribute to sound quality
and in not such as subtle way. We replaced all the power supply reservoir
capacitors with audio grade low ESR types, upgraded diodes to the IR HexFRED,
and upgraded all digital bypass capacitors with audio grade low ESR type. All
this lead to an increase in openness, detailing, and a fresher feel to the
music; removing some of the dark, heavy footed sound which spoiled performance.
Going back to the AC supplies we added a pair of large
Bybee purifiers to the AC input, followed by slipstream purifiers on the
transformer secondary supplies on the analogue side. This upgrade gave an
amazing increase in clarity and definition, you could now hear far more of what
was going on in the mix rather than your brain interpolating what you think you
are listening to and joining the dots! The sound was far more musical and
involving allowing you to get lost in the music.
Knowing how well the Bybee work on audio signals whether
it be low level or at the loudspeaker, we next added a pair of the Slipstream
purifiers to both left and right analogue outputs. This was a real ear opener,
you could now hear detail in bounds with a layer of ‘mush’ stripped away, voices
were more vivid, palpable and instruments sounded more vibrant, realistic, believable.
