Why PCB DAC's?

Whats the deal with everybody is using DAC PCBs like HiFiBerry?

Is there something wrong with USB sound cards?
I think about multichannel sound (SACD/FLAC) and there are no 5.1/7.1 PCB DAC’s.

Also why not just HDMI set to PCM and passing it to the AVR?

Principally because the RPi has only the one chip, the SMSC LAN9514-JZX USB and Ethernet controller, to do most of the comms. The result of this is that the USB bus can easily become ‘stressed’, leading to glitches and lowered sound quality. All USB ports and the Ethernet jack have a combined maximum throughput equal to one USB 2.0 port. I2S doesn’t go that way, so the sound quality is markedly higher.

That’s not to say that it won’t work, it certainly does, but as you increase the resolution, the quantity of bits to be moved increases dramatically and the port suffers.

On your last question, I’d rather let someone who knows these things answer…

Chris M

Yes the RPi is sharing USB and Ethernet. But I use a Odroid C2.

Apologies, I jumped to a conclusion…

Has to be sheer numbers, then. The RPi marketplace is huge by comparison with anything else that size. One can see the direct comparison with the Apple vs Wintel competition; there simply isn’t the range of stuff for Macs as there is for PCs. Given that, the Odroid C2 costs nearly twice the RPi3, simple volume issues answer your question. I agree, there are markedly capable USB DACs such as made by Chord Electronics, but at the low-cost end, it’s simply numbers.

Chris M

Also a reason, there is even a blogpost about it on the Volumio blog (look it up), is the very short path when directly using a single I2S bus from the source SBC to the PCB DAC.

I think all, I am not aware of any that don’t, DAC chips use I2S as their input, and maybe some I2C for controls if any.

So al other transport do mean coming from something producing digital sound, most likely I2S, conversions to others, sometimes even multiple conversions, back to I2S for the DAC.

Each conversion causes issues on many different levels that have to be countered somehow. So less conversion, probably a better signal :slight_smile:

A lot of factors are in play but, if you can afford it, a good DAC that can act as a master and can utilize asynchronous USB input and has a good power supply would be a very good ‘source’ for any Amp :slight_smile:

Verzonden vanaf mijn iPhone met Tapatalk

Oh, on multi-channel sound; using either HDMI or SPDIF can be good inputs to an AVR as the AVR does all the multi-channel decoding AND the D/A conversion.

Verzonden vanaf mijn iPhone met Tapatalk

I’m not talking about super expensive USB DACs.
But the ones for computers. There nobody seems to care about short path and conversions.
People who call themselves audiophile prefer USB because the sound card is outside the PC and away from electrical noise.

I have a old Terratec Aureon 5.1 USB MKII (just 44KHz/16bit) for testing and it works.

I ask myself if this cheap PCB DAC thing is just a temporary fashion.
I mean if you have a AVR with 24bit/192kHz BurrBrown D/A i guess it makes no sense.

I think it comes down to cost/convenience; I can buy a RPi for £32, a case for £10, a DAC for £50(I’m pushing the boat out here…), a PSU for £10 and voila! For <£110, I have a complete new digital player, able to give any other device a run for its money. I think that’s what motivates a lot of us, getting really good sound for very little. Along the way, there’s all sorts of rationalisations that can and are made about it, but…

On the computer side, no-one bothers about signal path lengths etc. because the environment is just so abominably noisy. If you get anything recognisable it’s a win.

I could give the official UK government reason for anything; because terrorism! Or I could use the physicists answer; because quantum!

If it works and you enjoy the music, then that’s good enough for me…

Chris M

So if i get it right there is no improvement with a PCB DAC vs HDMI.

Yep. So long as it works, that’s all that’s needed. It’s not a religious thing (although some enthusiasts may make it look that way…), so if you get really good sound out of , tell the world and the world may beat a path to your door. Or just go ‘Meh…’, worlds are funny things…

Chris M

Hello all, I know this is an old topic but I figured I would revive it instead of making a new one.

I have been using Volumio for a while now and my main system has been using an Allo Boss player (original version of Boss). I ended up picking up a Yamaha RX-V1800 AVR a while ago and have been using it as a preamp which is total overkill. I decided to try using HDMI from the Raspberry Pi to feed the AVR and use it’s DAC instead and I’m actually really happy with the results.

My question is just out of curiosity - have others around here played with the various I2S DAC out there and decided on just using the HDMI output instead?

I was using a Raspberry Pi 1 B with a Pifi Digi+ connected through optical cable to my Onkyo TX-SR313 receiver with a pair of Yamaha NS-F51 floorstanders and the sound was amazing! Then I changed to HDMI on the same setup and the sound is virtually the same which is VERY good.