Marantz CD 94 sch

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#6
Here's the list of modifications I did to Marantz CD94 CD player:
Replaced power supply + local decoupling capacitors with my favourites - 2200uF / 35V FK and 0.1uF / 50 NX Black Gates. Capacitor’s paralleling should be avoided.
Installed IEC power connector at the back (silver and then gold plated pins.)
Replaced RCA connectors with high quality types.
Removed back-to-back output signal coupling caps and installed AURI cap 4.7uF / 200V types. You can also try Black Gate 4.7uF / 50V C type. The choice really comes down to your taste.
Used silver ribbon cables everywhere... got rid of connectors.
Used WIMA green-cap polypropylene caps for analogue filtering.
Replaced the xtal with 11.2MHz LC clock with dedicated power supply (with 10 X 470uF / 16V KF Black Gates + two 0.1uF / 50V NX types). The placement of two 0.1uF caps is crucial for obtaining low noise conditions. This is very important – otherwise you are wasting you money on (EXPENSIVE!) LC clock. I removed the original decoupling capacitor that was supplied with the clock (4700uF / 25V, I think...)
Replaced 6 dual ICs with AD8066, AD826 and OP275 in analogue stage.
Replaced two focus / tracking ICs with NE5532AN.
Removed in-series-resistors from the power supply rails and installed ferrite beads. You need a bit of experimenting and CRO to obtain low noise “environment”
(I spent a lot of time getting the CD cradle to run smoothly!)

I did not have the circuit diagram unfortunately. It would’ve helped with mechanism servo and RF, though.

Good luck,
Extreme_Boky
 
#8
I look at the SCH...
I feel that is very good designed
Power Syply is better then usual
mechanics is very good

the tip is to override oversampling
(do not forget to back the mute signal fromSAA7220...)
and work on beter iv conversion

😎
I will probably change the SPDIF cable and connector and use the
CD94 as a transport only😉
 
#9
I use Philips CD 960 which is just identical except for the front panel design. This is what I did in my player:

- changed virtually all electrolitic caps to Panasonic FC. I paralleled 3300uF instead of 6800uF
- instaled Kwak Clock 7
- 3 TDA1541A supply caps and SAA7220 supply cap to BG N (47uF) and removed bypasses on them
- changed tDA5141 for TDA1541A S1
- change SAA7220P/A for P/B version
- change 14 TDA1541 decoupling caps for 0,56uF (one of the best so far are orange Philips MKT caps here, they are even better then some polypropylenes in this location
- changed 5534 op-amps for OPA627BP, all 4 of them
- mounted Siemens MKV output signal caps, BG N are also good in this position, but not as good
- I bypassed all signal path traces from TDA1541 upwords with Cardas solid core enameled wire
- changed PS diodes for MUR860
- mounted IEC power socket

I still have to experiment with soldering transformers primary wires directly to IEC socket (there is some power filter over there) and i also didn't try bypassing big PS caps with orange Philips MKT so far (always worked very good in other players).

The bottom line is this player so far is the best sounding CD player from old Marantz/Philips players based on CDM drives and TDA1541A. I still haven't tried Marantz CD 80 and CD 94MKII (I probably won't as I move to building separate DAC-s and transports from the scratch), but I had Philips CD 304MKII with all the same mods applied and is much inferior to Philips CD 960/Marantz CD 94
 
#12
For me the first things is remove the digital filter
Click to expand...


Yea right!!

And the sound sucks becouse original analog stage would have to be recalculated. I've done this many times and without separate analog stage (OPA660 or AD844 would be good example) the sound is worse than with digital filter in place.

And yes I know, everybody is raving about non os mods lately, but it's not always for the better 🙂
 
#14
zygibajt said:



Yea right!!

And the sound sucks becouse original analog stage would have to be recalculated. I've done this many times and without separate analog stage (OPA660 or AD844 would be good example) the sound is worse than with digital filter in place.

And yes I know, everybody is raving about non os mods lately, but it's not always for the better 🙂
Click to expand...


I have write "the first thing", not "the only thing".

😉
 
#16
zygibajt said:
I use Philips CD 960 which is just identical except for the front panel design. The bottom line is this player so far is the best sounding CD player from old Marantz/Philips players based on CDM drives and TDA1541A.

but I had Philips CD 304MKII with all the same mods applied and is much inferior to Philips CD 960/Marantz CD 94
Click to expand...

Distortion of CD960 is worse than CD304mkII & CD650.
I have three CD960 and three CD304mkII.
 
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