Clocking a Marantz CD-94

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In this player, the output stage already has low noise discrete regulation. Changing to separate 78xx 79xx will be a significant downgrade!!!!!! Renewing the cerefine caps in the regs will be an improvement. Also replacing the zenors with low noise vrefs (lm4040???) will improve the regulation no end. These regs only feed the audio output stage.

Whilst separate regulation in general is a very good idea, you need to understand the starting point before you comment!!!!

Separate 5v regs for 7210, 7220, ram and remaining hf components on the board on the side, will make a large difference. It is especially important to give the 7220 it's own low noise reg. it's a greedy chip to, but it's very important because it distributes the clock and it's derivatives to the 7210 and TDA. It is often blamed for less than optimal performance of players with these chipsets. In my extensive experience, decent regulation and careful attention to clock distribution is key to significantly lifting the performance ;-)
 
Did you download the clocking doc I linked too in one of my previous posts? This explains how to directly clock the 7210 and 7220 which you can do with your Trichord ( is it a clock 4?)

I would star by adding 4 7805 regs onto the board on the side of the player. You need to isolate the 5v rails for each of the 3 chips.
Start with the 7220. +5v goes to pin 24. Follow the circuit back across the link to the 2 caps c513 and c514. There is also another link below the chip you can remove and supply the new 5v supply from the separate reg just for this chip.

Do the same working back from pin 40 on the 7210, c505 and 506 are the local decoupling and next to c508 is a link which again can be removed to provid a separate 5v supply from the chip.

Next isolate the RAM chip q502. Local decoupling c508&9 and remove the link under c509 to provide a separate feed for the chip.

The original 5v reg in the player will supply the rest ;-)

Make sure you heatstroke the reg on the 7220 filter as it will get hot.

Later if you are happy, replace this reg for a boutique low noise reg like an SPower....it is worth it!

Back on the discrete reg, replace the red cerefines with similar value rubycon zlg's and the zenors that act s the vref in the regulator d805 and 806. These are 5.6v. You could try some to92 lm4040 5v in there which will drop the rail a fraction or try to find another low noise vref that is about 6v??

You got me thinking about mine now!!!! Lol!!!!

Edit!!! You could use an lm4040-2.5v in series with an lm 4040-3v or 2 x 3v in series to lift the rail a fraction.
 
Thoughts

Well this is a very thought provoking subject and I'm trying to decide where to draw the line between OCD and just making it sound nice. The other worrying thing is I have 2 Sony CDP 101 players and an original Marantz CD-63 all in pristine condition. Do I sell them on eBay and let someone else have the stress or make a start myself ??????/
 
Don't even start me on a cd 63!!!!

7f658d6f.jpg


d40c2db1.jpg


Lol!!!!!!!
 
Lol!!!

That didn't happen in 5 mins I can assure you!!!!

On you 94, seriously, a recap will work wonders. A clock and a single reg on the 7220 will be a the best vfm upgrades you can make ;-)

If it were me doing it again, I'd do those then just listen to the music.......


And yep, I love the oily based big black groved discs too ;-)
 
... Separate 5v regs for 7210, 7220, ram and remaining hf components on the board on the side, will make a large difference. It is especially important to give the 7220 it's own low noise reg. it's a greedy chip to, but it's very important because it distributes the clock and it's derivatives to the 7210 and TDA...

UV101,
You're basically telling FraserSoft that he should start redesigning his player in a fundamental way.

FraserSoft,
Is that what you wanted to hear?

OK, I'll try.

1. Analog supplies:
a) Unless you're going for Black Gates, leave Cerafines in place, they're fine.
b) If you want, parallel them with a small KP/MKP 10nF-0.1uF bypass caps, brand of your choice - Wima, ROE, Rifa, whatever.
c) Replace three polyester bypass caps around 1541 with the same mentioned above.
d) Put a 10-47uF electrolytic across D805/D806 zeners to reduce noise. They're not bypassed originally!!! Just solder the caps on top of zeners.
e) Increase +/- 14 Volt rails to 15 Volts. You have to play with R815-818 values to do that.
f) Get rid of 3.3 Ohm fusible resistors feeding opamps.
g) Optional - replace D807-810 with fast/soft recovery diodes of your choice.
h) Optional - replace R807-C807-R809/R808-C808-R810 with real current sources - current diode or Jfet. I used some Japanese two legged devices -10YD4.5 or something like that in place of the R-C-R string.

2. Analog part.
a) Opamps of your choice.
b) Redesign LP filter to have Bessel characteristic. FYI - SAA7220P/B data sheet calls for Bessel, but CD-94 have filters with Butterworth characteristic! Use polystyrene caps, if possible.
c) Replace R556-C576-R558/ R557-C575-R559 (non-ideal current sources, 2 ma BPO) with real current sources. I use PNP-LED combination there.
d) Replace 14 caps around 1541 with MKPs of your choice.

3. Digital part.
a) Put a couple of 22-47uF Oscons where needed on decoder board. They could be sourced cheaply on ebay or PM me.
b) Some jumper wires that connect +5V traces could be replaced with ferrite beads for better filtering.
c) Make sure you have "B" digital filter.

Is that enough for a starter? ;)
 
Last edited:
UV101,
You're basically telling FraserSoft that he should start redesigning his player in a fundamental way.

FraserSoft,
Is that what you wanted to hear?

OK, I'll try.

1. Analog supplies:
a) Unless you're going for Black Gates, leave Cerafines in place, they're fine.
b) If you want, parallel them with a small KP/MKP 10nF-0.1uF bypass caps, brand of your choice - Wima, ROE, Rifa, whatever.
c) Replace three polyester bypass caps around 1541 with the same mentioned above.
d) Put a 10-47uF electrolytic across D805/D806 zeners to reduce noise. They're not bypassed originally!!! Just solder the caps on top of zeners.
e) Increase +/- 14 Volt rails to 15 Volts. You have to play with R815-818 values to do that.
f) Get rid of 3.3 Ohm fusible resistors feeding opamps.
g) Optional - replace D807-810 with fast/soft recovery diodes of your choice.
h) Optional - replace R807-C807-R809/R808-C808-R810 with real current sources - current diode or Jfet. I used some Japanese two legged devices -10YD4.5 or something like that in place of the R-C-R string.

2. Analog part.
a) Opamps of your choice.
b) Redesign LP filter to have Bessel characteristic. FYI - SAA7220P/B data sheet calls for Bessel, but CD-94 have filters with Butterworth characteristic! Use polystyrene caps, if possible.
c) Replace R556-C576-R558/ R557-C575-R559 (non-ideal current sources, 2 ma BPO) with real current sources. I use PNP-LED combination there.
d) Replace 14 caps around 1541 with MKPs of your choice.

3. Digital part.
a) Put a couple of 22-47uF Oscons where needed on decoder board. They could be sourced cheaply on ebay or PM me.
b) Some jumper wires that connect +5V traces could be replaced with ferrite beads for better filtering.
c) Make sure you have "B" digital filter.

Is that enough for a starter? ;)

Electroj,

You're basically telling FraserSoft that he should start redesigning his player in a fundamental way.

I pretty much agree with everything you say except about the cerefines but I'm confused as to why my ideas are a redesign and your are not?????

My Philips 960 has considerably more done than I've suggested but I've tried to identify the best bang for buck mods as pointed out in my previous post.
 
Time out !

I am tempted to say that the Marantz is going into a Technics amp and a pair of Wharfdale Diamonds mounted on a bookshelf..... but I won't, nobody has taken into account the rest of the chain in the system.The way things are heading I won't live long enough to do all the tweaks you guys are suggesting so I will do some very basic sensible tweaks and leave it at that.
I can understand that once you start on the upgrading route (or creating a different sound) it can become obsessive. I don't have the understanding of the need to spend so much time and money on one piece of the chain.So many other factors can let the source down when it comes to what you are listening to and I am going to divide my time and limited spending power to the whole system.
The Marantz for now sounds quite good but I am busy mono blocking my 3rd Musical Fidelity Dr Thomas amplifier having just repaired it and then its time to split the xovers and fitting extra speaker terminals to the cabinets ending up with a tri wired tri amplified system....
 
Time Out !

UV101,

The difference is that my suggestions DO NOT REQUIRE extra wiring, hardware or cutting traces, even the PNP-LED CCS mod. ;)

Don't let the thread end up as battle between two opposing views, this is about me and my CD-94 and what I want to do with it and for now I am enjoying the music. I intend to get the tri wiring etc completed then lots more listening then perhaps I'll take some of the ideas on board for the CD 94.....
 
Did you download the clocking doc I linked too in one of my previous posts? This explains how to directly clock the 7210 and 7220 which you can do with your Trichord ( is it a clock 4?)

I would star by adding 4 7805 regs onto the board on the side of the player. You need to isolate the 5v rails for each of the 3 chips.
Start with the 7220. +5v goes to pin 24. Follow the circuit back across the link to the 2 caps c513 and c514. There is also another link below the chip you can remove and supply the new 5v supply from the separate reg just for this chip.

Do the same working back from pin 40 on the 7210, c505 and 506 are the local decoupling and next to c508 is a link which again can be removed to provid a separate 5v supply from the chip.

Next isolate the RAM chip q502. Local decoupling c508&9 and remove the link under c509 to provide a separate feed for the chip.

The original 5v reg in the player will supply the rest ;-)

Make sure you heatstroke the reg on the 7220 filter as it will get hot.

Later if you are happy, replace this reg for a boutique low noise reg like an SPower....it is worth it!

Back on the discrete reg, replace the red cerefines with similar value rubycon zlg's and the zenors that act s the vref in the regulator d805 and 806. These are 5.6v. You could try some to92 lm4040 5v in there which will drop the rail a fraction or try to find another low noise vref that is about 6v??

You got me thinking about mine now!!!! Lol!!!!

Edit!!! You could use an lm4040-2.5v in series with an lm 4040-3v or 2 x 3v in series to lift the rail a fraction.

Why you say 4 regulators is needed? You suggest to feed only 3 chips.
I am doing this now.. just wander.
Thx
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.