Add wings to your CDPRO2 or other DIY CDP!
CDM12 Controller Kit
Yo folks! Ever since I got my CDPRO2 up and running, I’ve been playing a lot of attention to the front end of the system. The front end to me, is more important than the rear end (unless your name is Kylie M). Of course, if you have junk speakers, you can’t hear what you are supposed to hear, but then if you have junk front end, there is nothing to hear at all!
There are a few truisms in audio that has, time and again, proven to be “true-er than others”. One of those is “Thou shalt not believe everything this yeo guy says”. Another more useful one is “where there is less signal processing, the sound is always better”.
Now I’m sure many have put forward the above truisms (including the one about that yeo fella!), but I had direct experience with the later when I hooked up the I2S signal from my CDPRO2 to my TDA1543 (let’s call this Route 1) and compared this with listening via the SPDIF output (Route 2). Using SPDIF, we need to use a digital receiver like CS8412 to convert the signal back to I2S, then only feed TDA1543. As you can see, there is some processing going on, converting the internal I2S to SPDIF, then SPDIF back to I2S when using Route 2. Which is pointless if we could tap I2S directly ala Route 1. Now the sonic difference is not subtle if this idiot can hear it! The sound is more “live”, more immediate, has more prescence. And I think this is all because of less signal processing. Comprehende?
All this is fine and life goes on beautifully until I discover TDA1545. Man, to my ears, this is a much better DAC overall and the next thing I know, I got anal and began fretting about signal conversion I2S-SPDIF-EIAJ. Yes, EIAJ is the format required by TDA1545, so I have to resort to using the endangered species CS8412 again. And I worry about the sonic degradation with all this signal formatting again. Grr…
So I yearn for a way to tap the EIAJ format directly from the CDPRO2. Studying its manual, it seems that the IS2 port’s output format is selectable via software and ONLY software. By default is I2S. The controller that came with my CDPRO2 kit doesn’t have any provisions for this so I’m left to programming a controller myself or the less glamorous option — seek help.
And so came Calv Acoustic Labs to the rescue! Again! Apparently while I was busying myself with all this hoo haa, our master DIYer has already been toying around with a controller for transport units based on the Philips CDM12 family. This includes Short Loader Mk3 used in Marantz CD4000, CD5000 and also our venerable CDPRO2. I wonder can I say “great minds think alike” just because I share the same idea as Calv Acoustic Labs’ head honcho, envisioning a controller that could select different signal formats? But there is a difference. While I pleaded for help, he programmed it! Now you know why I’m forever doomed as a novice diyer…
In addition to the controller, PCB, cables and connectors, the kit also comes with relevant info, like board layout, pin connections, wiring blah blah blah. Since I’m such a nice chap, I was lent a LCD display module.
Wiring everything up is pretty straightforward. The only thing I had to build myself was a 9VDC supply for the CDPRO2 motor. I could use my existing one but it’s too big. You’ll know why in a moment. Back then, I used to have a problem with Stocko connectors but guess what? I grew up! Now I find it pretty easy to use. Hee hee… And before you know it, I got everything wired up and running! [Note the ** DIY Paradise ** on the LCD display. Everyone knows I’m so full of myself!]
Close up of the PIC controller. Please forgive my home-made insulator…
Fitting everything into a small chassis. Another truism in audio. Never use a chassis too small… Real estate at the front and back portion will be utilized very soon!
So it works! Of course it works! Note that the “lent” display is too big to fit into the chassis. The hunt begins for a much smaller HD44780 based LCD display. Anyone?
Finally, with rest of the gang! I can tell you it made a very pleasant debut. Hee hee…
Right now still using SPDIF but this little monster of a TDA1545 DAC will be fitted into the chassis soon, and will be directly driven from the I2S port.
Aha! Now this is the beauty of this kit! Right now driving TDA1545 DAC which requires EIAJ format. Through clever programming, by pressing both “Play” and “Stop” keys simultaneously at power up, the I2S port is programmed to output EIAJ! The non-volatile memory of the controller is written so this will be EIAJ until it senses certain combination of “Play”, “Stop”, “Prev” or “Next” keys being pressed at power up. The various combination of these keys will give between I2S FS, I2S 2FS, I2S 4FS, 16-bit EIAJ FS, 16-bit EIAJ 2FS, 16-bit EIAJ 4FS, 18-bit EIAJ FS and 18-bit EIAJ 2FS! So it’s really up to you whether you want I2S or EIAJ at their various sampling frequencies. Cool eh?
Anyway, I prefer a one-box solution rather than playing around with so many boxes, like Thoreau, “Simplify! Simplify! Simplify!”. However, feel free to apply your engineering acumen to build “state of the art” machines of your choice. Now, if you wire the I2S/EIAJ output to a PC modem connector, you can then have your own dedicated DAC for optimum power supply isolation blah blah blah… You know, like this USD42k+ combo… (Click on image to read review by 6moons)
But you can do better! You can build various DACs and just select which format/FS you want, depending on which DAC chip you prefer at that instant. Ahhhhhhh…. This is better than sex!
Okay, if you have a CDPRO2 or planning to have one or planning to DIY a CDP based on the CDM12 family, and you just want to have your mojo with all these adult toys, you know who to contact. Calv Acoustic Labs at vt4c at hotmail dot com.
WELL DONE vt4c!
PS: Please note that my PCB is the prototype. A nicer version is available directly from Calv Acoustic Labs.