After reading much about diy audio I decided that the time was right to start building my first piece of audio gear. At that moment my setup could need a better CD transport, because this was the weakest link. There are many examples of diy CD player around on the web, but I choose the "Mini CD pro-2 Transport" from the Chinese manufacturer called Hifidiy also known as Aune. They make some nice kits using quality components.
The reason I choose for the "Mini CD pro-2 Transport" is because is of the CD-Pro2 module (VAU1254) from Philips. Lots of audio fanatics claim this transport to be the best in the world and I totally agree with them, although there are some other nice transports on the market too! The CD-Pro2 is is designed to deliver extremely good playabilty and very low mechanical playing noise. A unique feature of the transport is the pre-amplifier that moves along with the optics. The optics and laser are very secure aligned to the chassis. This all ensures quality tracking and very low jitter. A lot of information about the transport can be found on the Daisy Laser website.
Another reason to buy this kit was the nice chassis that comes with it. All panels of it are made of solid aluminium. The front panel looks nice and professional.
The CD-Pro2 is a top loader transport so in the top panel a sliding lid is mounted, which works very well. All holes for the PCBs, transformer, display and connections are pre-drilled making it really easy to build. Because I wanted to use a IEC power inlet with a mains filter I had to enlarge the hole for it. Using a mains filter the torroid transformer also needed to be placed a bit further away from the back panel. Apart from these adjustments I used the chassis just like it arrived.
At the time I began with with diy audio I had no experience with soldering and did not trust myself enough with it to solder all components to the PCBs. Especially the smd parts are quite tricky without having any experience! Therefore I cheated a bit and ordered the whole kit from Akustik Perfekt/Audio Intense. The man behind it is Horst Wenzel, who also builds some other nice stuff. It arrived with all components soldered. He changed some of the original Nichicon KG capacitors for Panasonic FC types, because he is convinced they are better sounding. I have not heard the transport with the Nichicon KGs, so I can not confirm this.
The aluminium plate onto where the CD-Pro2 transport is mounted normally rests on four metal springs to damp vibrations. There are now some rubber rings placed between the springs and the plate to provide better damping of any vibrations. I have done some tests without the rubber rings and noticed that the transport makes a little bit more noise when a disk is spinning. This noise is probably caused by metal to metal contact between the aluminium plate and the springs. Soundwise I could't hear any difference, but I figured that when there are less vibrations applied to the transport it must do something good in terms of tracking and jitter. When I finished the transport I placed it into my audio rack. This rack consists of glass plates on a metal frame. Because the transport weighs 7.5 kg and its feet are cone like shaped I was a bit worried that they would damage the glass plate. After a few days of worrying I decided to place the transport on a thin rubber mat. I immediately noticed that the sound became much more calm and detailed. I ques this mat is damping a lot of unwanted vibrations!
When the build finished it was time to compare it to my other transport. This was a Rega Apollo, which I used just as a transport by feeding its S/PDIF out to my Rega DAC. The Apollo is also a real nice CD player with a very good transport, so I was a bit frightened that my build couldn't compete with it. Luckily for me it could! The sound of the CD-Pro2 transport is more open compared to the Apollo. The Apollo tended to sound a bit restrained when switching back to it from the CD-Pro2. The CD-pro2 also reveals quite a lot more details without getting too clinical. Which is for sure a good thing!
After almost a year later it's still playing rock solid. I'm very happy that I choose it and I will probably never build another one anymore! This is mainly because of the rise of high resolution digital audio and not because I'm not satisfied with it! It still sounds much better then my Squeezebox Touch playing these high resolution files!
Upgrade: I2S output via Teleporter From Twisted Pear audio.
Although using the S/PDIF output it already sounds very good I thought I could even make it better using the I2S output of the CD-Pro2 transport. I2S is most commonly used to carry PCM information between the transport and the DAC in a CD player. The I2S bus separates clock and data signals, resulting in a very low jitter connection. The connection must be kept as short as possible and is therefore not suitable to use between a separated transport - DAC configuration. When using a LVDS transceiver is becomes possible to convert and transmit the I2S signals over a long distance and receive them on the other side of the line with another transceiver. This transceiver converts the signals back to normal I2S signals. The Teleporter module from Twisted Pear Audio (TPA) does exactly this. So I installed one Teleporter module in my CD-Pro2 and another one in my DAC. I tapped the I2S from the CD-Pro2 and connected it to the Teleporter modules as shown in the image.
There was one obstacle to overcome when using I2S from the CD-Pro2 and connecting this to my Buffalo DAC. The Buffalo DAC, also from TPA, makes use of the ESS ES9018 SABRE32 Reference 32-bit 8 channel Audio DAC. The CD-Pro2 outputs 48fs data, but the Buffalo DAC requires 64fs. The signals need to be re-clocked, so I used the Metronome module from TPA to re-clock and upsample its I2S signals to 192 kHz. The Metronome is placed inside my DAC and will not be further discussed here.
The key questions is "Does it improve the sound?". Well, it's very hard to tell. I have the feeling that it sounds slightly better compared to S/PDIF, but it could be that I desperately want it to sound better and therefore I might interpreter it as better sounding. At least it was fun to build and a good learning experience!