NOS
Marantz CD94MK2 mod
non-oversampling version of CD94 mkI and MKII too
I was for long time afraid of the NOS mod. It seemed too radical for my
taste. But under the pressure of the internet opinions I decided
to give it a try.
The circuitry which we must modify is on the vertical brown PCB on the
right hand side of the player.
A trained eye will spot the SAA7220p/B digital filter with 8x
oversampling, and SAA7210 demodulator chip which generates the I2S
datastream of 44 kHz.
We want to send the oryginal data straight to TDA1541A without the SAA
7220 manipulation.
Above
there is the first bypass already placed - leg 1 od 7220P/B wired to
the cable leading to leg 1 of the TDA.
We need three such bridges.
Above you see
black lines indicating where to cut the old traces at the exit of the
SAA7220
all bridges
completed.
While I was
already at it I decided to add a clock. Red wire is the new clock
signal, Yellow wire is the ground.
MAN what a
superb sound this mod makes. Everything becomes so good that I want to
shout at the whole world to DO THE NOS for your TDA !
For general note
- jump
HERE
This mod applies to almost all CD players but I have tried it only on
TDA1541 one. So it applies to tens of models which use this chip and
the digital filter 7220.
TO BE CONTINUED in
June 08 ...