Having an HAT is necessary to improve SQ?

Hi everybody,

I have a Pi 4 connected via USB to my DAC, Chord Mojo.

Do you have direct experiences that using an HAT, like the HiFiBerry Digi+ Pro, using the coaxial cable (not the toslink), I could have a better sound quality?

I have no problem in making this upgrade, I am only a little sad because I just bought two Flirc case (excellent) that I should waste if I buy an HAT (that needs other cases).

Tricky question :wink:

In general I would say: just try, the HAT’s are rather affordable I guess.
But I own a Chord Hugo 2 and I’m running it via USB as well. And in my case I’m rather convinced that is not improving when switching to coaxial.

If you go this route I would suggest you try out optical (instead of coax), because that’s what Rob Watts (designer Chord) advises.

Let us know!

‘Could have better sound’ is highly subjective… however, I will say I’ve tried on numerous HAT’s (optical, coaxial, Allo, HiFiBerry, IQaudiO) and found no quantifiable ‘sound’ difference to the simplicity of my current configuration of a RPi 4 mounted in a Flirc case (agreed, excellent) and onboard USB.

Spend your time and money enjoying the music rather than chasing the (audio) dragon…

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Thank you both for your answers.

I cannot follow the Rob Watts about the Toslink tip because my Toslink of the Mojo is already busy with the TV (with a wonderful sound quality I confess).

So my Mojo has only the USB and the COAX free.

I thought about the HiFiBerry Digi+ Pro for two reasons:

A kind user on another forum told me that “optical prevents transmission of any electrical noise from the Pi to the dac”;

Also, the “The Hans Beekhuyzen Channel” state:

Q: Is the USB on Raspberry Pi 4B still extremely noisy after that update or has that improved so that the best solution for sound Quality is now connecteting a DAC to USB or do you think it is stiil the best way to attache a specific HAT to the RRaspberry Pi 4B for best sound quality?

A: Yes, use a HAT board with USB if you’re serious about audio quality.

That’s why my needs of other users experiences…

Ah, I read elsewhere a total different thing, tell me what you think:

Use optical when you trust more on the source than in the DAC, while, use USB if you trust more in the destination (DAC) than in the source. It’s a jitter thing. I’m confused. :grinning:

Well, the ‘extremely noisy’ statement is rather bold. At least with my ears I’ve never heard a difference: the Chord sounds fantastic over USB.

You ever do those tests? Usb vs spdf vs optical?

I totally changed my setup now, I never tested the spdf vs optical because I only used optical with the TV and USB with the Pi 4 (with Roon endpoint).

(I realize this is a Zombie post but felt like typing this out anyway)

This is a complicated question. Most people answer based on their understanding, or misunderstanding, of Pi USB bus vs the I2S bus which feeds the HAT.

The more important question should be: What is the better interface on your DAC? Some, most, a lot, of DACs have very poor USB implementations and that input should simply be avoided. In that case moving from USB, any USB, to SPDIF, any SPDIF, will give improvement.

But SPDIF, and the quality of the signal, matters more than USB because of the way clocks work different between USB and SPDIF. A really good USB input will be good with any USB feeding it but a good SPDIF interface still needs to see a quality, low jitter, bitstream feeding it.

Of course “try it” is the right answer but start with identifying what the manufacturer of the DAC recommends, what reviewers say, and finally what the community says about the quality of the inputs. Then go find a solution, within budget, that plays to that input.

Very true, Chord recommend optical for their DACs over usb and coax I believe as the preffered input.