Marantz CD63 & CD67 mods list

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disco

disco

Member
Joined 2006
Re: Re: transformer output

poynton said:

HI.
these are possibly not the best Txs to try - too many windings on the primary !
But if you want to try,
wire the primaries in series / parallel to give a centre tapped winding - centre tap to ground / hot ends to the DAC outputs
wire the secondaries in series - try straight to the amp via a 50k volume control [ the Tx must see a high impedance ]
Andy
Click to expand...

Thanks Andy, will try.

Would these Sowter 3575 do any better?

Kind regards,

Jaap
 
SimontY

SimontY

Member
Joined 2003
diymediahome.org
Evening modders,

I did a couple more minor mods yesterday and have been listening today for hours.

The mods:
Added the two remaining grounds to my star point that I'd missed previously, and connected the star to the IEC socket.

Changed output resistors from 100R/1/4w metal film to 33R 1/2w carbon film.

Changed CD04, CD07, CD15, CD16, (DAC) C510, C511 (decoder) from 47uF and 220uF/10v to 4700uF/6.3v Pana FC.

The sound:
More 'analogue': bigger, more controlled and detailed. Dynamics improved too: it seems there's a clearly lower noise floor.

I'm very happy - cheap upgrades for a good effect :D

(display still dead :dead: )
 
R

ratep2001

Member
Joined 2006
Bigger caps?

There have been several posts about using huge electrolytic caps for decoupling DAC, decoder etc. and I started questioning its adequacy.

I would expect that you start drawing large current from the 7805 regulator when you start it up, but this one is hopefully short-circuit tollerant and will recover. In the same time there is huge cap on the input, so the input and the output voltage will probably track each other until the final voltage at the output is reached.

However, I don't understand why do you want to use 4700uF/6.3V capacitor for the DAC drawing approximately 2+3+35=40mA current? I don't have the numbers for the decoder. You can probably use it with the same success on a switched-mode power supply giving 5V and several Amperes...

You can never put that huge capacitor directly across the supply pins of the DAC; so you will always have the impedance of the interconnects deterioriating your HF performance. I think it is much better if you use modest electrolytic on CD04/05 and then do the decoupling with 100n X7R 0805 or even 0603 SMD right on the chip pins or even putting several caps with different values in parallel. These ceramics or maybe PPS foil have a very low ESR and ESL, so when they are put in parallel with the electrolytics they will always give lower equivalent resistance and better wide bandwidth effectiveness (like when the ESR and ESL of the electrolytic start deterioriating the cap performance, the ceramic cap will take over and extend its effectiveness into higher frequencies).
 
G

gy21

Member
Joined 2006
my.hifi.nl/index.php?user=1651
Re: Bigger caps?

ratep2001 said:
There have been several posts about using huge electrolytic caps for decoupling DAC, decoder etc. and I started questioning its adequacy.

I would expect that you start drawing large current from the 7805 regulator when you start it up, but this one is hopefully short-circuit tollerant and will recover. In the same time there is huge cap on the input, so the input and the output voltage will probably track each other until the final voltage at the output is reached.

However, I don't understand why do you want to use 4700uF/6.3V capacitor for the DAC drawing approximately 2+3+35=40mA current? I don't have the numbers for the decoder. You can probably use it with the same success on a switched-mode power supply giving 5V and several Amperes...

You can never put that huge capacitor directly across the supply pins of the DAC; so you will always have the impedance of the interconnects deterioriating your HF performance. I think it is much better if you use modest electrolytic on CD04/05 and then do the decoupling with 100n X7R 0805 or even 0603 SMD right on the chip pins or even putting several caps with different values in parallel. These ceramics or maybe PPS foil have a very low ESR and ESL, so when they are put in parallel with the electrolytics they will always give lower equivalent resistance and better wide bandwidth effectiveness (like when the ESR and ESL of the electrolytic start deterioriating the cap performance, the ceramic cap will take over and extend its effectiveness into higher frequencies).
Click to expand...

I think you misread. I was talking about C803/804 (3300uF) and C813/C815 (4700uF) in the power supply department.

Anyway i'm mainly follwing the tnt mods and 6h5c document on modding the cd67.
 
6h5c

6h5c

Member
Joined 2004
raylectronics.nl/index_en.html
Re: Bigger caps?

ratep2001 said:
You can never put that huge capacitor directly across the supply pins of the DAC; so you will always have the impedance of the interconnects deterioriating your HF performance. I think it is much better if you use modest electrolytic on CD04/05 and then do the decoupling with 100n X7R 0805 or even 0603 SMD right on the chip pins or even putting several caps with different values in parallel. These ceramics or maybe PPS foil have a very low ESR and ESL, so when they are put in parallel with the electrolytics they will always give lower equivalent resistance and better wide bandwidth effectiveness (like when the ESR and ESL of the electrolytic start deterioriating the cap performance, the ceramic cap will take over and extend its effectiveness into higher frequencies).
Click to expand...

Hi ratep2001,

I agree, a small cap can perform better than a big one. Big ones have more parasitic inductance because of their construction. For the amount of current it is certainly not nescessary.

Regards,

Ray.
 
poynton

poynton

Member
Joined 2005
6h5c said:


Hi gy21,

You can safely increase those if you like :yes:. There's no fire-hazard :clown:

Regards,

Ray.
Click to expand...


Hi.

Ray , are you sure? I have heard that some CD Players have a tendency to spontaneous combustion !


The size and type of capacitor after the regulator is a matter of some debate.
Some say that a large cap. does not allow the regulator to react fast enough.
Certainly some regulators do not like low ESR caps such as Oscons.
Also if the cap is large, a reverse diode must be used.

Andy
 
G

gy21

Member
Joined 2006
my.hifi.nl/index.php?user=1651
poynton said:



Hi.

Ray , are you sure? I have heard that some CD Players have a tendency to spontaneous combustion !


The size and type of capacitor after the regulator is a matter of some debate.
Some say that a large cap. does not allow the regulator to react fast enough.
Certainly some regulators do not like low ESR caps such as Oscons.
Also if the cap is large, a reverse diode must be used.

Andy
Click to expand...

Wich cap do you mean with the cap after the regulator? C813?

On my player I did not touch the regulators, so they are the default ones.
 
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