Volumio High End Player

Diy and Tweaks Diy Volumio Projects
1

After my expierences with several players for the raspberry PI I finished my best player.
First I started just for fun with an diy dac with PCM1793 directly connected to the I2S port…worked very well. Now I was curious what is possible in terms of sound quality. First choice for the dac was PCM1794. This is my favourite dac at the moment, better than many newer and higher bit dac’s. Followed by an I/V stage with LME49720 and LME49710 output stage.
For internal decoupling and best sound quality there are 3 power supplies, seperate for the PI included hf filter and on/off circuit, one for the dac and the analog output stage.
The most difficult and even very important part is the I2S signal from the PI to the dac, it should be terminated on both sides. Best result I had with coaxial RG174 cable.
For the music data I’m using an external SSD harddisk.
I’m very satisfied with the result.

DSC_5855_DxO.jpg
DSC_5839_DxO.jpg
DSC_5841_DxO.jpg

4 Likes
2

Hi Alex,

Looks very interesting.
Well done!

Best regards
Erwin

3

Very nice!!! Where did you get the boards?

4

The boards are self etched with blue pcb material.

5

Hi Alex,

This looks great! Would you mind sharing some more info and perhaps schematics?

Guus

6

Hello Alex , what do you “i2s cable being terminated”?

Enviado do meu HUAWEI P2-6011 através de Tapatalk

7

For having a nearly ideal square waveform of the signal the wire should be terminated with serial resistors in the source and the end of the trace.
The resistors should be about 20-150 ohm, depends on the source, wires and dac. You can check the waveform with an oscilloscope and optimize the resistors.

8

Hi Alex thanks for the explanation:)
Do you use a separate masterclock or you are using the mstck from the dac?

1 Like
9

I don’t use a seperate masterclock. I use the BCK from the RPI and connect it together to the BCK and SCK at the dac. Very simple and works great.

10

Alex, where did you get your case and what size is it?

11

Yes! Please share info about the case, I’ve been searching all over the forums and internet for a case like that one (high-end like equipment) but it seems not easy to find them!

12

It looks like a hifi2000 case:
modushop.biz

Those cases are quite popular for DYI audio projects.
I’m planning on using on of these for my Odroid C2 - Soukris DAC - Hypex NCore all-in-one project as well.

13

Hi, sorry for my late reply.
Right, this case is from modushop. I’m using these cases for the most of my projects. With a few modifications very usable.

14

Curious about your discrete analogue stage.

Care to share your schematic?

1 Like
15

The schematic is nearly the same from tha datasheet
ti.com/lit/ds/symlink/pcm1794.pdf

The op-amps are LME49720HA and LME49710HA. I have modified the output filter with higher impedances than in the datasheet for lowering the load of the I/V stage.

16

Hello,

Very interresting project! what powersupplies do you use there? and why three different ones?

best regards

paul

17

All power supplies are diy. There are 3 separate ones to give best performance for every stage and to avoid interactions between digital and analog parts.
One power supply is for the raspberry only, it has an extra mains filter for a clean power rail. All computers are noisy, so the raspberry as well. This keeps the noise far from the analog stage.
The second one is for the DAC and the third one for the output stage.

18

My player got a little brother. It is a hat dac for plugging direct on the raspberry. You need an external power supply and 2 cinch jacks.
I think it is one of the best sounding solutions for the raspberry at the moment.
DIAL-DAC.jpg

19

Hi, Alex. Connected right? RPi > pcm1794: 12 > 6+7, 35 > 4, 40 > 5 . gnd > gnd ?

20

all right!

PI >>>>>>>>> PCM1794

12 —BCK/SCK— 6+7
35 —LRCLK------ 4
39 —GND-------- 8 DGND
40 —DATA------- 5