The CD Transport

[Peter Daniel]

This is how it's being done in ML31.5: Stereophile: Stereophile: Mark Levinson No.31.5 Reference CD transport

"More important from a sound-quality point of view, they remove the Philips-supplied 1000ppm-accuracy oscillator from the servo board and replace it with a TCXO (Temperature-Controlled Crystal Oscillator). Spec'd at 5ppm and run at a 256fs rate, this is mounted on its own sprung printed circuit board next to the output. And even more important with respect to sound quality, the transport has changed conceptually. That master oscillator controls not the transport mechanism but the output stage, a flip-flop chip that could be considered a 1-bit FIFO. The output data thus have the maximum timing precision, which is where it is needed. The mechanical drive is slaved to the output stage and therefore needs to be able to respond to its demands, which is why a 2x drive mechanism, with its inherently fast response, comes in useful. (This topology, referred to by Madrigal as Closed-Loop Jitter Reduction, or CLJR, was developed for the less expensive No.37 and Proceed CDD transports.)"

[Peter Daniel]

And this how I prototyped it in my transport. Please see attached edited CEC schematic (according to board layout the RCA output is actually taken from pin 9 of the flip-flop)

I added a small board with two chips and few additional parts (used exactly same chips as CEC, some experimenting here with different types maybe worthwhile and will follow), crystal is Citizen and output transformer Scientific Conversion. I didn't use output coupling cap, it's not really needed here as long the DAC does not show any input DC offset.

I didn't use any additional regulator (TL0 does not use one either) the power, data and ground are simply taken from main board, another wire connects clock signal from output board to main board (use resonator pad which is further away from LC78601 chip)

How does it sound? Well, I didn't find anything wrong with the transport in a first place, with a mod though, it has a bit less of edginess and thin sounding, which some people may find sort of annoying. It produces sounds that are better defined in space and possibly more refined. It's certainly worth trying and I would be interested how others find it.

[Peter Daniel]

That concludes the transport construction chapter. I also have two other well respected transports: CEC TL0 and Levinson ML31.5 but use Shigaclone most often. It really matches the other two units performance.

[Peter Daniel]

Now comes the PS part.

48VA Hammond transformer (166L24) fits perfectly in a Hammond 1590T enclosure. The diodes are mounted directly to connector socket and the whole thing came out quite elegant and simple.

[Peter Daniel]

I recently tried slightly different PS enclosure, made out of 3 x 2 aluminum tubing and 2 x 2 angle. The transformer type is the same I'm using with my DACs (229D20)

[woodturner-fran]

Great thread peter - this is a great help to !anyone who has or is building a shiga......

Fran

[jtktam]

a work of art as always

-joe

[ejfud]

You always amaze me with your builds.

[leoparleur]

Hello Peter,

This resumé was a great idea. It will become a nice reference to all. I always asked myself why there still wasn't one, now it's there. :0)

Cheers!

Guy

[Tea-Bag]

Yep, I realize now, that I dont have to do much to get mine in the box downstairs going. Of course i dont know about re-wiring the display and buttons yet.