Marantz CD63 & CD67 mods list

[RCruz]

Originally posted by Andre Visser
Hi Ricardo

With your op-amps and Caps there should be no problems in wiring the output directly, I would like to know if there is any difference in sound quality. The other resistors are only for ground reference, needed when you use the series Caps on the output and the 100 Ohms to protect the output stage from the short created by the muting transistors.

Thank you André.

I will bypass everything from U210 U214 to the output plugs.

I already removed output caps and mutting transistors so I believe I can bypass the series 100ohm resistors and the parallel 10k and 100k.

I also removed the 100p ceramics from the output without problem.

My biggest doubt was about removing the 10ohm series (R619 620) but i am sure that with this new opamps I will not have instability.

I will report the results briefly.

Merry Christmas to All.

Ricardo

[Glenn2]

Some op-amps do not like driving capacitive loads.

An interconnect is a capacitive load.

I would always put a 75 ohm resistor between an op-amp and the output jacks. This buffers the op-amp output from the interconnect's capacitance, with no noticeable penalty in sound quality.

You may not need it with all op-amps, but it's good practice and means any op-amp can be used.

A small capacitance on the output reduces the phase margin of the circuit and can introduce ringing or even oscillation.

It's only my opinion but I wouldn't even consider leaving it out, even if it appears to be OK in some cases.

Here's some theory.

[RCruz]

Originally posted by 6h5c
After modding a Marantz CD63 and a CD67OSE I decided to make a list of all the various mod's I found here and elsewhere on the internet.
I'd like to donate my files to this forum, for all to enjoy!

Hi Ray

Why do you leave a 47R R659 / 660 after bypassing the HDAM with a wire ?

I am a little puzzled because I read several quotes instructing I can bypass everything and this seems to be contradictory.

Best Regards and hope you have a good Chrystmas.

Ricardo

[Andre Visser]

Hi Glenn2

I agree with you that it is safer to use a resistor on the output of an op-amp.

With the op-amp Ricardo is using the spec is 100pF load on the output which generally should be Ok if the cable length doesn't exceed 1m.

Regards

André

[RCruz]

Originally posted by Glenn2
Some op-amps do not like driving capacitive loads.

An interconnect is a capacitive load.

I would always put a 75 ohm resistor between an op-amp and the output jacks. This buffers the op-amp output from the interconnect's capacitance, with no noticeable penalty in sound quality.

You may not need it with all op-amps, but it's good practice and means any op-amp can be used.

A small capacitance on the output reduces the phase margin of the circuit and can introduce ringing or even oscillation.

It's only my opinion but I wouldn't even consider leaving it out, even if it appears to be OK in some cases.

Here's some theory.

Originally posted by Andre Visser
I agree with you that it is safer to use a resistor on the output of an op-amp.

With the op-amp Ricardo is using the spec is 100pF load on the output which generally should be Ok if the cable length doesn't exceed 1m.

Thank you Glenn and André

Your comments finally gave me some insight to the problem.

I now understand the function of all the parts and will experiment with some quality resistors.

Will report soon.

Ricardo

[Fidelity Audio]

Merry Christmas and a Happy New year everyone

Brent

[quan]

Merry XMs to you all gents, saviours!!!- from down under. Quan.

[Malefoda]

As you may know I've fitted a Super Regulator, from Sercal aka Brent, in the best CD53 of the world (yes I have no competitors for you are all with 63/67 ).

Here is the pictures of the player at the moment.


The SReg 5V is powered via C813. While upgrading I was listening to a CD52 MkII SE (wich sounds so warm and dull, very round on low-half...).
First I've turned the CDP to check the ribbon cable and the SReg setup: succes! It works fine, had a 10 sec test for CD the playback at low volume... it worked and it seemed that I've gain a bit of bass for what I can tell.
Let's have an hear at the warmed up CDP:
What depth! Yes the change is neat: treble more clear, a bit more bass, overall better. My feeling is an all better, but an even better treble, clearer and faster. Voices has gain air around, depth. I was a bit louder than usual, wich means less distorton I guess. No more Marantz sound as mine sounds sharp and tight beside the unatural warmth of its elder brother!
I've managed to make a pipe to guide the Flea's led light through the removed headphone socket, a faliure as the led is not that shining and the pire carried almost no light out.
The stupid try I had...

Again, Merry Christmas guys!
Matthieu

[Mikko H.]

Hi folks and merry Christmas for everyone. I have followed this forum quite a while. This inspired me to by an upgrage kit to my CD67SE from Sercal. No I have installed the parts and the sound has improved a lot. But, there are some buts. I hope you can give me some advices.

I have made following mods:
* D801-D804 changed to schottkys
* C1 clock for dac powered with S-power reg.
* Sercal discrete output stage with BG STD psu caps and with BG N output cap. (original opamp filter and HDAM bypassed totally)
* DAC caps changed to BG STD (4 pcs).
* All digital electrolytes changed to Rubycon ZLH.
* some shielding over critical parts/chips and flat cables.
* damping to enclosure

Sound is quite good after mods but I have a noise (sounds like white noise) problem on both channels. Noise level is equal on both channels. Measured with oscilloscope, the noise level is 15mV (p-p) and this can be heard clearly when amp volume is a high and there is no signal coming from CD. The output stages are located over HDAM:s and they are (also) grounded to HDAM copper enclosures. This extra grounding reduced noise a little bit. The power wires to output stages are coming on top of the pcb with twisted wire straight from C803, C804. The output stage output is connected straight to RCA connector and muting circuit is disconnected from RCA connector. Input signal to output stage from DAC is coming on top of pcb with twisted wire (no external series resistor). So can you help me where to start on reducing this noise? I could guess that the problem might be the DAC output signal.....

About the sound. I have noticed that the sound is very detailed and the midrange is very good. Highs are a bit too bright and horn instruments sound a bit cold. Bass is good. My hifi setup is following:
- CD76SE player
- Sphinx Myth 5 integrated amp( sofar slightly modified, will be more)
- Qed 3 interconnect and Qed silver anniversary speaker cables (bi-wire) [yes, these are a bit too bright]
- ProAc tablette 2000 speakers on posts.

Br, Mikko from Finland

[SimontY]

Hi Mikko, and Merry Christmas to all!

I have lots of noise too, and I'm not sure where it comes from, so I'll be eagerly following developments.

Re. your sound, I would think about changing the interconnects to ones with pure copper conducters, and putting the CD player on wooden cones. You'll also need to let the new upgrades "settle down" if you haven't already done so. The sound from the CD player should be fairly neutral, so there could be some brightness elsewhere throwing your sound out of balance now that the CD player is more precise.

Simon