Marantz CD63 & CD67 mods list

[SimontY]

Originally posted by Biskit
Any news on the custom TX.

I'm thinking of potting my frame tranny in a mu metal can.

Gordon

Mu-metal is the dogs for shielding EMI isn't it? Won't you be better off getting this custom toroid though?

[Fidelity Audio]

Yeah custom or KI tx. Much more headroom

[6h5c]

Originally posted by poynton
Or a noisy tube or FET ??
I would also be tempted to play with the values of the 620pf caps ?? The original circuit has more filtering - a passive filter may also be an answer??

Originally posted by poynton
Did you use ecc88?
What B+ did you use?
Did you check the current through the FET?
What voltage did you get at the A-K junction.

Hi Andy!

Well, I know a bit more now. The remaining noise is not coming from a tube or the FET.
I measured in my CD63 to compare the results, and it too has this noise at the output .
Would you, or somebody else with a scope be so kind to verify this on his player? With the player in stop-mode and no muting circuit and HDAM installed, I can measure allmost 20mVpp.

For Thorstens circuit I used ECC82 on a B+ of about 220V. I didn't have 4k7 around for the PSU series resistor, so I gave each channel a 6k8. I upped the B+ a little so the voltage behind it reaches the desired 190V. The A-K voltage should be about 100V. The voltage over the FET is less than expected, because the DAC's 2,5V DC voltage is divided by the 10k-22k combination. The current through the FET is about 4mA. The FETs are not very equal....

Regards,

Ray.

[Fidelity Audio]

I have 22mV on outputs with no HDAM

[6h5c]

Originally posted by Franz G
Absolutely no noise, just music!
Gerald Gessner is selling his modifications, so I am not allowed to publish the exactly circuit.
It is really just a LC filter, 1mH in series with the signal, 10 nF to ground.
And: no output cap!
When I use this player with my DC coupled PL519 amp, then I have absolutely no cap in the signal path after the DAC chip.

Franz

Thanks Franz. I think the noise is there, but you'll have to set your volume to max. to hear it. The tubestage's amplification is less, so I noticed it when I turned the volume up.

Originally posted by rowemeister
I have 22mV on outputs with no HDAM

Thanks Brent, for measuring so fast !
Thank goodness i'm not the only one, apparently this is normal for this player.

Regards,

Ray.

[Bas Horneman]

Hi Ray,

Just popped in to say this is indeed a cool thread...!!! Plenty of co-operation. And a lot of interested people.....gotta get me an old Marantz somewhere..

So is the tube stage all you dreamed of?

Regards,
Bas

[6h5c]

Originally posted by Bas Horneman
Hi Ray,

Just popped in to say this is indeed a cool thread...!!! Plenty of co-operation. And a lot of interested parties.....gotta get me an old Marantz somewhere..

Regards,
Bas

Hi Bas!

Thanks for the compliments! How's your PP project?
I haven't had time yet to put your chokes in my amp, but PSU designer shows it's a good thing. Been busy with this tubestage...
Maybe next week, I'll let you know what the results are.

I've got a CD63 for you, but it's already modded....

Regards,

Ray.

[poynton]

Originally posted by 6h5c


Thanks Franz. I think the noise is there, but you'll have to set your volume to max. to hear it. The tubestage's amplification is less, so I noticed it when I turned the volume up.



Thanks Brent, for measuring so fast !
Thank goodness i'm not the only one, apparently this is normal for this player.

Regards,

Ray.

HI.

To find the source of the noise and so reduce / eliminate it, you need to measure earlier preferably just after the dac.



Andy

[poynton]

Originally posted by Bas Horneman
............ co-operation. ..............

After all............


...............Resistance is futile ..............

[Bas Horneman]

Thanks for the compliments! How's your PP project?

Haven't started yet...maybe tonight

I haven't had time yet to put your chokes in my amp, but PSU designer shows it's a good thing. Been busy with this tubestage...
Maybe next week, I'll let you know what the results are.

NO hurries mate.

I've got a CD63 for you, but it's already modded....

Thanks...but that would be a waste of a great sounding CD player..since I'll would probably end up using it as a transport for my RAKK DAC.