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.

nos tda1541As1
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.

nos tda1541As1

Above you see black lines indicating where to cut the old traces at the exit of the SAA7220

nos tda1541As1

all bridges completed.

nos tda1541As1 marantz

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 ...