Skip this paragraph if you know HiFi equipment well. For those who don't know HiFi or only use HiFi for music, DAC stand for digital-to-analog converter. It converts the digital signal from a, say, CD to analog signal that is required for amplifier and speaker. It is usually built inside the CD player of your HiFi set. For serious HiFi fever, they sometimes change the DAC to tune the sound quality of their HiFi set. Some CD player has digital output. Such output feeds into a DAC, like the one I posted here, to convert the digital signal.
This DAC is a DIY kit. In other words, I bought the whole and complete kit and assembled it myself. The kit includes all electronics, print circuit board, transformer, chassis, chassis accessaries and even power cord. Only the cables for internal connections and the human efforts are not included. I bought it via a local hifi diy forum, which organises group-buy from a China web site. The forum is here and the China web site is here. The forum is very well organised for group-buy. But when it comes to technical discussion, this English forum is much better because of international participants.
The DAC uses components:
- LM2940T for +5V for digital
- LM317, NE5532 for +5V and +3.3V for analog
- TIP41C, NE5532 for +-15V for audio parts
- CS8420 for digital input
- PCM1794 for digital-to-analog conversion
- NE5534 I/V
- OPA604 low pass filter
- 2SC1815 output buffer


After soldering all the components on the PCB. I put it inside the chasis that comes with the kit. The wire at the bottom of the photo runs the AC power to the power switch at the lower right corner, and in turn to the primary of the transformer (also comes with the kit). There are 3 secondary from the transformer to the 3 power supply/regulator of the PCB. The digital input from CD player feeds into PCB via the coaxial at the upper left corner. The analog output runs from the lower part of the PCB to the RCA socket. Other wiring are for power, lock, and constant current source indicating LED.


Finished. I put it under the CDM12 CD player (only the transportation, my other DIY project). Not bad, right? But I found that the power LED is too bright.
That's all. Thanks for reading.