Marantz CD63 & CD67 mods list

[Fidelity Audio]

LMAO very good indeed

You know when they have failed you get a sweet sticky residue!

Also which one is the better cap? is it the GU or the PA?

Brent

[Malefoda]

Hi guys,

I'm happy the forums are back (with better editing fonctions) as I have no music right now. And the answer may be obvious for some of you, so I need to ask before mess in the player.

I've fitted +5V regulators around, they all work fine.
I've added a third line from the Flea trough a 100R direct to the Decoder CrIN, removed all things on the path wich were R193 and caps. Unfortunately I did not kept them in a separate box and they are mixed with others parts... and the FSM is not the right one...

When turn the player on the tray close, the focus gets OK... but the disc does not spin. Error 10, Radial error. As far as I can understand the FSM it's the Decoder which drive it, no voltage at R513 (even if it's PWM for wich I don't know if my DMM can have a look at it...).

I just hope you get that when the Decoder is out of clock...

Any idea guys?

Matthieu

(PS: if I need to go to factory set-up (and why not the older simple 100R feed between DAC & Decoder?) someone may be kind to gimme values of C521, U193, C522 and R related going to CrOut... thanks!)

[mickie]

Hi guys,
...i could use your advice regarding ground-layout on my 67; as i wish to optimize the ground, connecting dac and decoder to a star point (C813 main digital smoothing cap) i noticed that i may run into trouble because of the clock-coax-cables i use... .
My point is, if i run two coax-cables from my DEXA-Clock to feed the signal to dac AND decoder and connect the shields to ground, the two "grounds" of dac and decoder are connected on the clock-output via the shields, right?
Is this a problem, do i create a ground loop? Ho can i perform my "star-ground" in this case?
Reagrds,
Mickie

[Glenn2]

You should connect the coax between clock and DAC grounded at both ends.
You should connect the coax between clock and decoder grounded at only the decoder end.
If you are powering the clock from the player's main supply you would not normally connect a return ground for the supply either (this would also create a ground loop) but I think the clock you are using is different in this regard and requires it, owing to galvanic isolation of the output.

[Glenn2]

The only ground connection to the clock output should be as close the DAC clock ground pin as possible, not any star grounds.

[Thomo]

Hey guys - Nice work being done by all I think

I too regulated the driver IC's last week, I've used a 12v tx with large smoothers and 12v SPower regs. It's a massive improvement, particularly in bass and detail.



Cheers, Lee.

[mickie]

Thanks Glenn!
Yes indeed the DEXA Clock has an islolated output, nothing to worry about ground loops if you use only ONE coax....
I already tried cutting the shield on the decoder's side...but things got worse (soundwise); i'll try it the other way round as you suggested.

The only ground connection to the clock output should be as close the DAC clock ground pin as possible, not any star grounds.

eerm, sorry i'm afraid i didn't get that, can you elaborate..?

Would you recommend terminating the cable, if so, which resistor value should i choose?

regards,
mickie

[Malefoda]

Originally Posted by Thomo

Hey guys - Nice work being done by all I think
Cheers, Lee.

A faulty player from a working one is not really nice work

[Glenn2]

Originally Posted by mickie

Thanks Glenn!
Yes indeed the DEXA Clock has an islolated output, nothing to worry about ground loops if you use only ONE coax....
I already tried cutting the shield on the decoder's side...but things got worse (soundwise); i'll try it the other way round as you suggested.


eerm, sorry i'm afraid i didn't get that, can you elaborate..?

Would you recommend terminating the cable, if so, which resistor value should i choose?

regards,
mickie

Well if you try it different ways and one sounds better, trust your ears!

If you have the DAC section connected to a star ground, that's fine (if done properly) but the clock ground must be connected to close to the ground pin of the clock input.
I was just hoping your clock output wasn't grounded at the star ground, which I don't think it is, so you're OK.

Basically, do not think of gnd points as 0V. 0V is just a reference point to measure another voltage against.

If you think of gnd at the regulator as 0V then what is gnd at the DAC? If the wire connecting the two has some resistance (and it does) and it has the DAC return currents running through it, then Ohms law says that the wire develops a voltage across it (V=I x R), so there is a voltage difference between regulator gnd and DAC gnd.

The DAC is seeing the voltage between the clock input and clock ground pin (DAC ground), so that is where you want your clock input and clock ground connected. If you add in the impedance of a clock connection to star ground instead and the DAC connection to star ground, you add in the voltages created by the currents running in those grounds.

The grounds get polluted by noise currents just like the +V lines.

This is where we need Martin Clark as he's much better at that stuff and can explain it better than me too.

Anyway, if you just connect the clock input and clock ground where they tell you to, i.e., where the original crystal and capacitors were, you'll be fine because that is the best place.

[mickie]

ok, thanks, these ground "issues" are more complicated then i thought....

so if i were to optimize it, where do i start? Can you give me some spezific instructions regarding the CD67?
For example, the "digital " ground of the DAC is connected to the ground near the signal (cinch) output ground; what i wanted to do is to cut the trace and run a wire to original "star" which seems to be on C813... .
Any comments?