Re: CD63 Crystal Replacement
Im glad someone did this mod as I have done it with 5ppm crystals to mates cdp with good gains (I dont think people have believed me in the past thinking i'm some mongoloid lol).Also I always ground the can and fit the rubber ring.
Rowey
pantera6 said:
So... I finally got stuck in and replaced the stock clock crystal with the 5PPM one I ordered. To my amazement, it actually worked once I swapped crystals, as the last time I swapped the crystals, I got a whole lot of unintelligible characters on the display so I swapped the original crystal back. (Later on, and thanks to Brent, it turned out to be a weak 5V supply on the microprocessor pin – unrelated to the crystal).
So these very subjective perceptions only relate to swapping the standard CD63 crystal (~50 PPM??) with a high stability crystal (5PPM). I custom ordered mine from here http://www.rakon.com/models/crystal-search
The first thing that I noticed was the 5PPM crystal did not change the character of the sound… it only made it better. For instance, I could here more texture in the lower mids and voices sounded more “natural”. But something was a miss.For some reason, the bass was shallower and the treble was not as extended as before. Puzzled, I tried thinking back to what else I had done to the stock crystal, and then it dawned on me… I had grounded the outer can. Also, the new 5PPM crystal didn’t have the rubber damping ring like the old Marantz one did, so I pulled the player apart again and grounded the new crystal’s outer metal sleeve and wrapped it tightly with blu-tac.
Wow… what a difference!!I don’t know if it was the damping or the grounding that did it, but the base and treble extension returned in spades!! It sounds even more neutral now, less Hi-Fi. If I hadn’t changed the crystal, I would never have known what was missing, as the player sounded great before…but you have to do it to see what you’re missing!! Now the frequency extremes are arguably greater and the mids are sooo natural. Really good rhythm and timing… and did I mention the neutrality J I could only imagine what a dedicated clock would do… which is now on my list (along with the servo clock mod).
What really got me is the difference grounding the crystal and damping it made. Doing these two things made a greater difference than swapping the standard one with the 5PPM crystal.
So there you have it. To sum up, replacing the stock Marantz crystal with a high-stability crystal (5PPM) that is also grounded and properly damped really does take this player up another notch . I had also implemented the Acoustica clock hack and had a dedicated regulator feeding the stock crystal, so these mods did help the overall sound. Wonder how much more a dedicated clock would do??
Next on the mod list (being performed this long weekend)… Ray’s excellent transistor output stage that will replace my LM6172 opamps and HDAM!Will let you know how it goes if anyone's interested.
Have a great (mod-ful) weekend guys!
Champi
Im glad someone did this mod as I have done it with 5ppm crystals to mates cdp with good gains (I dont think people have believed me in the past thinking i'm some mongoloid lol).Also I always ground the can and fit the rubber ring.
Rowey
Re: Re: CD63 Crystal Replacement
Yes Rowe, you are a mongoloid 
But I believed you 😀
My [unanswerable] clock question is: what difference is there between an old Audiocom DVC-1 clock and a Superclock2?
Simon
rowemeister said:
Yes Rowe, you are a mongoloid
But I believed you 😀
My [unanswerable] clock question is: what difference is there between an old Audiocom DVC-1 clock and a Superclock2?
Simon
gy21 said:I just did the first coax mod yesterday, I did not have time to listen to the result.
By the way, there are more coax mods, does anyone have more specific info (cd67) where to put those coaxes?
gy21 said:
Follow the sick and sida lines between dac and decoder. Cut track and fit coax here. Make sure CPU still gets signal though!.
Also mclk (pin 4 DAC) to decoder. This carries 16mhz to decoder.
I have a 63 but these are correct for 67 also
Brent
rowemeister said:
An externally hosted image should be here but it was not working when we last tested it.
Is that the connection from rd14 to r104, see schematic of 67 above, can someone confirm?
gy21 said:
Yes thats the one mate. The 63 has a res like the 67 and a cap next to decoder.
Brent
Thanks Rowemeister!
I don't understand sick and sida? I cannot find those terms in the service manual.
Are there maybe other names for these names?
rowemeister said:
I don't understand sick and sida? I cannot find those terms in the service manual.
Are there maybe other names for these names?
One question, does it matter what kind of coax cable you use? I used George L's cable. Wich is a coax type cable and is a very good cable.
But i don't if it is 50 ohm or 75 ohm coax.
But i don't if it is 50 ohm or 75 ohm coax.
So I was able to get a CDM12.4 off e-bay should be here next week. It was for a lot of 2 and paid 33 USD their NIB so now I will have a spear also. 
Regards
Dave
Regards
Dave
6h5c said:
I only did the 16.9MHz MCLK that runs from the DAC to the decoder for starters. It's a job that requires a good light, and a sharp scalpel knife 😎. I bought the cable at Farnell, it's from Nexans. Overall diameter is 1.22mm! The inner conductor is a 0.1mm copper plated steel wire. Very cool stuff! Felt like a surgeon this afternoon 😀.
I used 75 ohm because that has less capacity/m.
The characteristic impedance doesn't matter much, because it's such a short run, compared to the signal's wavelength. I learned that here. Very good site, with lots of info. So I went for less capacity.
Standard there's a 470R resistor in series with the MCLK line. I noticed the clock signal became quite weak at the decoder after I inserted the coax, probably because of the larger capacity. I tried lowering the resistor to 75R. But the input of the decoder appears to be at ~2.5V DC, and there is actually a DC current running between the two chips
My first impression of the sound is that it has become more like my tubestage 😀 😀.
This is definately a mod I can recommend. Thank you Brent!
Regards,
Ray.
I was just reading some old posts when this post from Ray came across, is this also something I have to worry about when I do the coax mod?
The CD67 has a different decoder compared to the 63. In the 63 there's standard a coupling cap present between the decoder and the DAC. To make the signal a bit stronger after the coax mod (the signal weakens a bit due to the extra capacitive load) you can lower the 470R resistor, or even completely remove it (haven't tried that yet). But as the DC current between the chips gets higher, I recommend to put a 1n coupling cap in series.
Regards,
Ray.
Regards,
Ray.
disco said:
Hi Jaap,
Yep, C521, a.k.a. RD14.
If the output resistance is lower, less filtering of higher harmonics occurs. This can make the square wave a bit steeper or more 'square'. The drawback is that more ringing can occur due to the capacitive load. My guess is that the pro's outnumber the con's, but you'd better listen for yourself. My scope is not that good, so I didn't measure anything here 😀.
Regards,
Ray.