Marantz CD63 & CD67 mods list

[poynton]

Originally posted by rowemeister
I changed C120 and C122 to 16V 3300uF Pana FC.

I changed these to give more headroom. I am also going to seperate the two 5V inputs to the servo has one is for analogue and the other digital.

The voltage between the two points is 4.983V in stop mode and 4.931V when playing. Tracking etc does not affect the voltage

Hi,
Not too late then!

Current on the analog +5v at this point is fairly low and fairly constant, I should think.

Can you measure any ac noise on the line at this point?

Andy

[Fidelity Audio]

The ac noise at this point measures 0.2mV pk-pk in stop and 0.3mV pk-pk in play.

My Audiocom Invisus to the DAC measures less than 0.1mV pk-pk in play or stop mode

Brent

[poynton]

Originally posted by rowemeister
The ac noise at this point measures 0.2mV pk-pk in stop and 0.3mV pk-pk in play.

My Audiocom Invisus to the DAC measures less than 0.1mV pk-pk in play or stop mode

Brent

So No worries then??


Andy

[Fidelity Audio]

not really, I do have the better caps fitted though

[6h5c]

Originally posted by Luke
22mV noise seems quite high, thats about 1% of full output.
Can this player be reengineered to get rid of the noise?

Hi Luke,

I didn't expect this high value. The DAC datasheet says 102dB S/N, so I guess better should be possible. I think the analog section is the problem, maybe not symmetrical enough. If there are more people that would be so kind to measure their output, to confirm this, that would be great.

Originally posted by Franz G
I am very sorry, I just tried it: full volume, >100dB/W speakers (see foto) attached: dead silence.

First: The most critical voltage seems to be AVDD (pin 21 and 22 from the SM5872). It is recommended, to derive it from the 12V "audio" voltage.

Franz

Nice speakers . Just a thought Franz: is your muting circuit still active? My CD67 with relais is also dead silent. That's why I never noticed the noise before.

Pins 17, 19, 21, 22, 24, 26 are all called "analog" supply pins, but the output signal is far from analog: it's a PWM signal. So I wouldn't connect it to the analog PSU. I used a separate regulator for these pins, and draw power from C813.

Regards,

Ray.

[6h5c]

Originally posted by poynton
It may be worth feeding this point fron the 'cleaner' analog +5v and also deriving the VRef +2.5v from a more stable source, TL431.?


Andy

Hi Andy,

I changed the 150R divider resistors (R124/125) to 1k, to give better filtering with the caps. In the CD67 they are standard 1k. I didn't think of a TL431 yet , it is an easy drop-in replacement.

Regards,

Ray.

[poynton]

Originally posted by 6h5c


Hi Andy,

I changed the 150R divider resistors (R124/125) to 1k, to give better filtering with the caps. In the CD67 they are standard 1k. I didn't think of a TL431 yet , it is an easy drop-in replacement.

Regards,

Ray.

Hi Ray,

The Vref does not need to be exactly 2.5v ( I think ) dut it does need to be 'clean'. These are in effect audio amps....... what effect does the psu line noise have on performance??? Cleaning it up cannot do any harm!


Pins 17, 21, 22, 26 supply the output amplifiers so could be considered analog. I think the optimum solution is to power the DAC from 3 independant 5v supplies, clock, digital & analog. Well, thats my plan!

The supply to the servo chip is 5v analog to pin12.
VRef is taken from the feed to pin28, digital supply!

Andy

[Fidelity Audio]

I can honestly say seperating the 5V rails to DAC and Decoder helps the cdp no end. Everything just feels more complete.

Also I have fitted the HF upgrade components and my initial response here at work is wow! it isnt a massive improvement but its good and cheap. Everything is more controlled, better resonance on piano and the vocals are very smooth.

Diana Krall The girl in the other room sounds soooo good.

Roll on the RF mod.....tomorrow hehe

[poynton]

Hi,

So what have you replaced??

C504 with a BG?
Some silver / micas
Holco resistors??

why not c503?

Now all you need to do is feed it +5v from a clean source not the digital 5v and feed the HF signal via screened coax dirct from the HF preamp board.

Andy

[poynton]

Originally posted by rowemeister
.................. The girl in the other room sounds soooo good.

Most women do sound better in another room!