I am Ralf from Frankfurt, Germany.
I use Volumio on a Cubox pro. I started with RPi + Hifyberry and Volumio. I improved my setup with RPI-DAC.
I found out, that the psu is very important and than I build my own psu for the RPI-DAC. Every step brought an improvement. So I decided to design my own DAC and pcb.

I investigated the theory of DACs and digital audio and discovered a lot of myths. In short: There is no need for 24 Bit audio. It is possible to convert and save analog audio without any loss to digital audio. 16 Bit is more than you need. Just examine the math behind this.You don’t loose anything within the music when limiting it to 20kHz. A sample rate of 44kHz is more than you ever need! The thing you have to take care about is jitter and a very good psu. In my DAC I used 6 PCM1794 in parallel and a passive IV convertion.

Do not believe to get high end audio with RPi and some of these funny mini DACs (hifiberry)! But Volumio is really great!

The complete DAC!
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I Ralf, nice work !!!
can you give me the main differences in sound between your own dac and the other too?

Hi nuno,

thank you. The wirering is a litle chaotic! But works!

First of all, you need a DAC (chip). I decided to use the PCM1794 from TI. This is the best DAC you can buy.
Then you need a well designed layout, a very good psu and high quality parts (resistors, condensators). The main difference between the most other DACs is that I used 6 PCM1794 in parallel.
They all feed one passive I/V stage with just 60 Ohms. So between my DAC and my power amplifier is just a resistor no other active parts (OP amps). 6 PCM 1794 give enough power to drive my power amplifier. With 6 DACs working in parallel you minimize all statistical errors to 1/SQRT(6). The result is a very clean sound and a very deep and broad sound stage. There are other DACs using similar principles (DDDAC dddac.com/). But DDDAC is a NOS DAC. All filtering and oversampling of the PCM1794 is turned off. This is the wrong way to go! But you have to examine the math behind DACs to understand this. Just be aware of people telling you, that they can hear a difference between 24bit and 16bit audio or between 44 kHz and 96 kHz. (You have to compare studio master quality recordings in 16/44 and 24/96 quality. )
There is no difference! Just believe in math.

Some words about the psu. A good psu will cost you about 250,- EUR. It starts with very good trafos and ends with high quality regulators to feed the PCM1794. You also have to separate the digital and analog domains.



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