• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Confused about the best way to get digital audio into my DAC

GoldenOne

Not Active
Joined
Jun 25, 2019
Messages
201
Likes
1,469
So, I should shortly be receiving a Holo May dac, and i'm a bit confused about some of the things that people have said about it/the spring online.

Typically, I'd just connect my DAC to my PC via a decent USB cable (Just a Supra one, not super cheap, but nothing snakeoil)
A lot of people have said that the holo dacs sound better when fed I2S input, rather than USB. And i'm wondering if there could be any truth to this.

As far as I can see there are three options:

Option 1: Connect DAC to PC straight USB
Option 2: Connect a good SPDIF bridge like the Singxer SU-2 or Matrix x-SPDIF 2 via USB, then the dac to the bridge via I2S
Option 3: Use a Pi2AES and connect the dac to the I2S output of that, so that in theory you avoid anything to do with USB altogether.

People have said that option 2 sounds better than option 1, but the only reason I can think of for this to be true is if the USB module or clock in your dac was worse than the bridge, which for some dacs may be true. But the Holo May has a much better USB module so I can't imagine this would be true. (The early spring dacs did have an iffy USB module which was later upgraded so this could be the reason for the subjective opinions about USB vs I2S online)

Am I missing something? Is there some other benefit to using a bridge vs just connecting the DAC via USB?

With Option 3, I'm guessing the benefit here is that you have nothing to do with USB at all. the Pi communicates via I2S to the pi2AES board, and then you output I2S from that whilst utilising the high quality clocks, so there should be no issue at all.

If anyone could shed some light on why Options 1/2/3 could be better than the others I'd really appreciate it.
 

tmtomh

Major Contributor
Forum Donor
Joined
Aug 14, 2018
Messages
2,636
Likes
7,497
It would appear all the sound-quality difference claims are based on the conviction that the USB connection sends noise down the line. That very well might be true - but as amir's tests have shown, you have to have an exceptionally noisy USB output on your PC, combined with an exceptionally poor USB implementation on the DAC, for USB noise to result in any degradation of performance in terms of the analogue signal that emerges from the DAC's outputs.

So if it were me, I'd go with option 1 and forget about it.
 

Trdat

Addicted to Fun and Learning
Forum Donor
Joined
Sep 6, 2019
Messages
967
Likes
396
Location
Yerevan "Sydney Born"
Most manufacturers (although we don't know how accurately or how definitively they are testing there digital inputs) recommend using USB.

Like Tmtomh said, go with option one and forget about it.

In no way we are trying to be rude, but your better off researching another aspect of audio that interests you which can lead you to an overall better understanding of a new skill set.

Analysing what digital input to use on a DAC, well it pretty simple most DACS accept USB and that is the most common connection. Unless we have a measurement of each digital input on that particular DAC we will never know which one works better so no point even deliberating about it.
 

dinglehoser

Active Member
Forum Donor
Joined
Nov 19, 2018
Messages
108
Likes
226
+1 to the two posts above. Unless the DAC has an irretrievably broken USB implementation, and/or something in your setup causes a ground loop when using USB, you won't hear the difference. IME the latter is far more frequently the case, and it should be immediately obvious whether there's a problem.

(A technically competent USB implementation will be effectively agnostic to the power and signal quality of the upstream USB source.)
 

BDWoody

Chief Cat Herder
Moderator
Forum Donor
Joined
Jan 9, 2019
Messages
6,948
Likes
22,627
Location
Mid-Atlantic, USA. (Maryland)
People have said that option 2 sounds better than option 1

Welcome!

Lots of people say lots of things...unfortunately, most people also don't implement any controls on their listening, leading to purely subjective impressions which can be misleading at best.

Another vote for simple USB. If you have USB noise issues, try optical, or just go optical...or whatever. One shouldn't sound different than another in most competent implementations.

Don't worry...you aren't missing anything.
 

Koeitje

Major Contributor
Joined
Oct 10, 2019
Messages
2,292
Likes
3,880
I just use what's practical for my use case, I haven't noticed the difference yet.
 

JeffS7444

Major Contributor
Forum Donor
Joined
Jul 21, 2019
Messages
2,347
Likes
3,509
Option #1 ought to be the best option, minus the silly $55/1M USB cable unless you really like the looks of the thing.
 

RayDunzl

Grand Contributor
Central Scrutinizer
Joined
Mar 9, 2016
Messages
13,204
Likes
16,985
Location
Riverview FL
If anyone could shed some light on why Options 1/2/3 could be better than the others I'd really appreciate it.

I just use what's practical for my use case, I haven't noticed the difference yet.


Yeah.

I have a chain of devices, and don't do multichannel...

Currently: Digital sources -> Switch -> Focusrite 4Pre (experimenting) -> DEQ2496 -> miniDSP OpenDRC-DI -> DAC

The PC has USB out, but I convert it to Optical on the way to the switch.

The Switch takes coax or optical S/PDIF and outputs both.

I'd use USB if intermediate devices that accepted it would also output USB (they don't).

No external I2S connections here.

No problems, audible or measurable.
 
Top Bottom