Marantz CD63 & CD67 mods list

[SimontY]

Originally posted by rowemeister

"Re-jig of power supplies next, and feed the servo chip from its own regs. I think I'm nearly done then!"

No you are not and you know it LOL

Brent

No sir, sorry sir. I will endevour to place super regs on every voltage rail. I will put better smoothing caps in my external supplies. I will change the HF and RF amp components to precision parts (resistors and caps). I will use a Superclock 3 to feed my DAC and my DVC-1 clock will be dedicated to the servo. Output caps will be exchanged for Black Gate AC type.

Then will I be done???

Simon

[Fidelity Audio]

LOL

Brent

[Glenn2]

Originally posted by SimontY
Re-jig of power supplies next, and feed the servo chip from its own regs.

I don't know if this helps or not, but I modded a 63 years ago (i.e., not the 67SE I'm currently molesting).

The servo controller (TDA1301T) is fed the 5V regulated supply (albeit the same one as everything else in the stock player) but the servo amps (TCA0372 x3) are fed the unregulated +/-10V raw digital supply (actually a bit higher than 10V)

It may have been only because it was still using the one transformer, but I got a huge leap in bass quality when I regulated these servo amps. They draw large currents and it probably stopped the noise generated leaking back into the supply for everything else. Just hypothesising here though.

IIRC I used LM317/337 and regulated them to +/-7.75V

(BTW - In the 67 they run off +5V/0V and have their own dedicated reg - that's what the other 7805 does.)

Having said all that, if you've already got a separate trafo for the DAC supplies, the gains here may be small or non-existent. Just thought it worth bringing up.

(P.S. decided not bother with the tennis today!)

[SimontY]

Cheers Glenn (lol @ molesting a CD67se)! Another to add to the list I think. If your theory is correct it won't make a big difference in mine. I'm using a few extra transformers already. I'd like to try it though (probably after seperated 5v regs for servo chip.)

Simon

ps - this rain is ridiculous now. There are ducks SWIMMING in the local park's cricket pitch! Not just paddling - swimming, really.

[philpoole]

Probably the most action a cricket pitch has seen in years ;-)

It always surprised me why servo amps aren't regulated (my CD940 is the same), Martin told me in a another thread it was due to (if I recall) feedback in the servo loop making it fairly accurate without regulation, but I hadn't thought of its affects on other parts of the circuit, being unregulated.

Maybe one for me to try too one day.

[martin clark]

Yebbut the particular problem the 63 suffers from is that there is only one5v reg...for everything!

Stopping interaction is always a good thing. I'd back Glenn's proposition about reduced interaction for the 'better bass' phenomenon of getting the servo loop(s) off the same raw supply that feeds the clock, the dac, the dac's analogue stage... etc...

[Phil you recall quite correctly, but I meant in the sense that the servo loop bandwidth is entirely set in firmware in the decoder (in Philips chipsets anyway). This is one reason Naim, amongst others, write their own firmware... ]

[philpoole]

Naim really do things properly. Huge number of regulators, for the DAC alone, nevermind the rest of the player, AND rewriting the firmware.
I used to write firmware (not for CD players). Its not exactly fun.
They're dedicated!

[Fidelity Audio]

I did a wee bit of firmware writing myself , eeprom data for Pat testers and calibrators when I worked for Fluke and on a personal note I used to mess around with my cars ECU mapping

And yes it's not fun at all

Brent

[martin clark]

on a personal note I used to mess around with my cars ECU mapping

Modified power supply? Me too

[Fidelity Audio]

Yeah I changed my injector duration , rev limit , idle and some basic WOT parameters

Brent