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24 bit USB DAC

admin_exported

New member
Aug 10, 2019
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Many DACs arriving, but so many seem to be assuming if you want quality you'll be feeding an optical signal in. But to feed an HD audio signal via optical without sound artefact issues takes some serious tinkering at the operating system level of the device decoding the audio files (which I doubt many people here or generally have the knowhow to do). It gets more confusing when you think that most people will be feeding optical out from CDs which produce at best 16/44, i.e. providing input support for higher assumes a computer as feed and therefore USB would be the most obvious choice as it gives the DAC the best chance of performing at the level it was designed to do. So...

(a) why aren't more DACs coming with support on the USB for 24/96 or higher?

(b) what DACs do have USB supporting 24/96 or greater?

(just some idle thoughts while snowbound 43cm/16.5" and threatening more...)

Cheers

Chris
 
T

the record spot

Guest
Quite a few available on the Pro-audio scene; Roland's Cakewalk UA-25EX offers an ADC/DAC 24/96 capability for around £160 or so. Native Instruments Kontrol 1 has more MIDI production functions, but could also be used and would sit nicely within a system for similar money.
 
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Anonymous

Guest
Thanks for the suggestions of the Roland and Native Instruments options - from an hifi audio listening perspective how would these compare to say the (sadly lacking the 24/96 USB support) Rega DAC?
 

daveh75

Well-known member
Jul 31, 2008
592
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18,920
You could look at MGL Audio Labs range of DACs, they have 24/192 support and start at ?99.

Though they now only supply the DAC 'modules' so you need to source, build or have an enclosure manufactured (they supply plans/instructions/manufacturer list)

The result of this approach though, is the DACs are considerably cheaper than they used to be (my Mini DACPre was around ?900 when i bought it, though i had it upgraded to include extra inputs and R/C, the equivilent DAPRE 200 now starts at ?300)

The Benchmark DAC1 USB also has 24/192 support.
 

The_Lhc

New member
Oct 16, 2008
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Isn't the USB on the Arcam rDAC 24/96? *checks manual* oh yes, it is but you need to use coax iff you want to get beyond 96KHz...
 
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Anonymous

Guest
Ahh, must have missed the 24/96 support on the rDAC - makes it the best contender as a solution at the entry price point then. How would the rDAC compare sonically to the DACmagic?

Anyone any thoughts on why Rega, Cambridge Audio et al have not implemented better USB support?
 

ID.

New member
Feb 22, 2010
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I thought that USB was generally limited to 24/96 (sorry no idea of the technical reasons/explanations). The benchmark is limited to 24/96 via USB.

I think you can get better rates through it, but probably requires the manufacturer to develop/implement their own driver for the computer.

the only "DAC" that I had heard of thus far that was doing 24/192 was the DAC section of Esoteric's new CDPs

http://www.esoteric.jp/products/esoteric/k01/indexe.html

http://www.esoteric.jp/products/esoteric/k01/indexe.htmlhttp://www.esoteric.jp/products/esoteric/k03/indexe.html
 

The_Lhc

New member
Oct 16, 2008
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putt1ck:Anyone any thoughts on why Rega, Cambridge Audio et al have not implemented better USB support?

Well the DACmagic is few years old now, so they may not have seen the need at the time, I daresay the next iteration of the DACmagic will include better USB support.
 

chebby

Well-known member
Jun 2, 2008
1,233
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I plan to try and arrange a three way comparison demo (preferably at home) between the Rega, rDAC and my Beresford.

I use all three inputs (USB for iTunes, optical for BluRay/DVD/BBC iPlayer from BDP-S370 and co-ax for the old DMR-EX78 that I still use for Freeview Radio and recording/playback from it's HDD) so - on balance - I am not too bothered about 24 bit capability from USB as I only use USB for iTunes and occasional Youtube stuff.
 
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Anonymous

Guest
chebby:
I plan to try and arrange a three way comparison demo (preferably at home) between the Rega, rDAC and my Beresford.

Looking forward to your reviews...

chebby:

I use all three inputs (USB for iTunes, optical for BluRay/DVD/BBC iPlayer from BDP-S370 and co-ax for the old DMR-EX78 that I still use for Freeview Radio and recording/playback from it's HDD) so - on balance - I am not too bothered about 24 bit capability from USB as I only use USB for iTunes and occasional Youtube stuff.

I'm growing my music collection primarily from real music sources, kinda rules out iTunes and Amazon ;) - so Society of Sound, HD Tracks, Linn Records - 24/48 flac and upwards wherever possible. All the lowest res stuff I have is ripped CD (cdparanoia wrapped in abcde to maximise the quality of data ripped). And that's why my current setup is optical out; it just seems that it would make more sense to get the DAC to take care of the conversion of the flac to audio, rather than the onboard sound card. That and I have an idea about a really neat future solution based on a tiny embedded PC and some clever supporting technology ;)
 

SteveR750

Well-known member
Mar 11, 2005
530
21
18,895
putt1ck:
Many DACs arriving, but so many seem to be assuming if you want quality you'll be feeding an optical signal in. But to feed an HD audio signal via optical without sound artefact issues takes some serious tinkering at the operating system level of the device decoding the audio files (which I doubt many people here or generally have the knowhow to do). It gets more confusing when you think that most people will be feeding optical out from CDs which produce at best 16/44, i.e. providing input support for higher assumes a computer as feed and therefore USB would be the most obvious choice as it gives the DAC the best chance of performing at the level it was designed to do. So...

(a) why aren't more DACs coming with support on the USB for 24/96 or higher?

(b) what DACs do have USB supporting 24/96 or greater?

(just some idle thoughts while snowbound 43cm/16.5" and threatening more...)

Cheers

Chris

Chris, what are they? I know that optical s/pdif is far from ideal, but what are the limitations?
 
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Anonymous

Guest
It's mostly about jitter and the requirement to produce the audio signal in realtime. FLAC 24/96 is a lot of data to decode at both steps in the process (tops 3200kbps or an order of magnitude more information than the highest resolution MP3). I realised the sheer impact of the quality of the source material and D/A conversion when I heard two Dynaudio demos at the Bristol show - same speakers, one demo with an iPod, one with Chord Red Reference CD player...

A general purpose operating system e.g. Windows, MacOSX and your home/office equivalents in the Linux world are built to do lots of things, not one thing well. Then there is the issue that S/PDIF is a compromised form of the original pro audio setup - at the time the compromises were about reducing cost, but now of course the cost difference is minimal which is sort of ironic as despite this the consumer audio world seems to have stuck with it. So we have a compromised compromise when we try and use a general purpose operating system to provide information over S/PDIF, with the two types of connection having different issues to overcome.

Generally the issues surrounding optical TOSLINK are easier to mitigate than those with coaxial insofar as the TOSLINK issues are based on the quality of the cable, its length and the paths through which you make it travel. In particular keeping the connection short and keeping it from having to go round any tight bends or being squashed are the most important. A 6m cable neatly routed around the outside of a room is likely to be an issue, a 0.5m cable running in a constant radius of 150mm will be good. Even better (marginal, but better) would be .1m cable in a completely straight run - but for the life of me I couldn't figure out how to do that and still be able to switch both devices on...

Then you need an operating system that has been optimised for the purpose, not built to do lots of things reasonably well. And ideally hardware that has been optimised, which is where the challenges start and why I want to try going down the USB route. So the operating system is not that much of a challenge. Run a Linux realtime low-latency kernel, preferably headless (without a graphical interface device nor producing a graphical output) to prevent any other processes getting involved, and cut down the other processes to a minimum. If you must have a local graphical interface make it monochrome or utterly optimised for minimal graphics processing overhead, you can do the pretty bit somewhere else (and should). Keep it simple, the software that plays music should be just good at you know, playing music (unlike UPnP...), the method you use to get the media store available should also be simple - I use SMB, NFS would also be an option, and an FTP mount would be an interesting approach (very, very low overhead, very fast).

Optimised hardware is harder. The first priority to me was to remove noise; electrical noise was reasonably easy to mitigate, use a TOSLINK. The other noise is the fan found in most computers, but there a number of fanless options now, particularly if you don't need a lot of processing power because you've optimised the operating system; use an SSD rather than traditional hard drive and shortly afterwards you have a computer that acts a lot like a piece of hifi - you press the button on the front to turn it on and off and you only know it is on because there is a light on the front. It makes no noise at all, even you put your ear to it.

But optimisation is about selecting the best possible components and putting them together in an optimised way. Not having my own PCB assembly plant I can't do that, so the sound card which decodes the FLAC, the motherboard quality, etc. is a compromise that I cannot surmount, hence my desire to push the full audio processing part to the purpose-built DAC.

OTOH I think when my EB2s arrive I'll have a setup that would make most audiophiles want to listen some more, I just can't resist looking for further (cost-effective) optimisations...
 
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Anonymous

Guest
unleash_me:
Ayre Acoustics QB-9

Nice. I'll start saving before I audition it though...

"If you haven't heard it, you don't have an opinion." - Ivor Tiefenbrun

I disagree. My opinion on the QB-9 is similar to that for most audiophile gear costing over a £1000/unit: I bet it's lovely but there's no way I'm being allowed to have one, not until the house is finished, estate replaced and those exotic holidays have been had. At the very least...
 

eternaloptimist

New member
Mar 29, 2009
5
0
0
My Wyred-4-Sound DAC-2 does 24/192 asynchronous USB in... and sounds great! :D

Lots of DACs have 24/96 and generally don't require proprietary drivers.

Above 24/96 ie up to 24/192 requires proprietary drivers.

Google "asynchronous USB DACs" and see the debate re: conventional and asynchronous USB. The latter relies on the DAC to clock the incoming data stream so there is less potential for jitter (although newer DAC chips are more forgiving). The former uses the computer to clock the data (as I understand it, please correct me if I am wrong) so there is the potential for jitter... hence... asynchronous is generally thought to be a good idea!

I suggest spending some time at www.computeraudiophile.com - some excellent reference materials there.

Good luck!

Cheers,

D
 

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