Article: Arcam rDAC Asynchronous USB DAC Review

[JDFlood]

I would save a bit more and get the WireWorld Starlight, it is worth it. You get additional detail and great musically. The ultraviolet has more detail and is a little cheaper but is a little harsh. I don't know of anything cheaper that is very good.<br />

<br />

JD

[lo1979]

many thanks

[lo1979]

Good evening thanks for your review , i was wondering if is possible to keep connected both optical and usb cable end switch between them when needed.<br />

<br />

Many thanks<br />

<br />

regards

[Audio_ELF]

Lo1979, the Arcam rDAC has a push button in the top to change input from Optical --> Co-ax --> USB<br />

<br />

Eloise

[Bezmania]

Yes, you can connect different sources at the same time. I've got mine connected to an airport express with optical, to a sat-receiver with coax and to a laptop with USB. Manual switching only, though.<br />

<br />

[lo1979]

ya got it, i was just wondering if for example, streaming music via usb while optical attached to satellite box would add any sort of interference or decrease audio quality .<br />

<br />

cheers

[lo1979]

hi guys yesterday i ran into this, would you recommend it as a good upgrade?<br />

<br />

http://www.squeeze-upgrade.com/squeezeupgrade-lineaire-voeding-voor-arcam-rdac-p-1610.html?language=en<br />

<br />

<br />

thanks

[Elberoth]

I have recently tried Teddy Pardo rDAC PSU with my rDAC. This is basicly a very high quality linear power supply (the stock rDAC power supply is a noisy, switching affair), based on a Teddy Pardo 'superregulator' concept. <br />

<br />

Replacing the stock PSU brings a notable improvement. The rDAC, which is great for the money, becomes really outstanding. There is more clarity, more resolution, more HF air. You can hear much deaper into recording, there is more spatial clueas and much more stage depth. <br />

<br />

The TP PSU bring better delineation of images, there is much greater space between the performers on stage, the sound is more palpable. <br />

<br />

I recently gave it to a friend for a week to try in his system, and basicly, could not listen to the rDAC with the stock PSU anymore. The sound was coarse and congested.<br />

<br />

It is not an inexpensive upgrade, but well woth the money IMO. <br />

<br />

http://www.teddypardo.com/

[Bezmania]

<br />

I don't notice any degradation or interference in my setup. However, I could easily imagine ground-loop issues or interference from cheap sparky psu's. I make it a point to minimize ground connections between links, so both SPDIF and RCA interlinks are grounded at the source end only. TOSlink is optical, so no ground issues there.<br />

<br />

I also guess that it's theoretically possible for digital input on an inactive input to show up in the digital path. However, that would be a major design flaw. I've given it a quick try and notice no such effects.

[lo1979]

ok thanks

[lo1979]

how much this teddy pardo' s psu cost in usa??<br />

I m in europe so i would have to add duty tax, <br />

the one i posted before cost only 138 euros, do you reckon that would be a good upgrade??<br />

<br />

<br />

thanks

[Elberoth]

I'm also EU based. Just ask Teddy to describe the item as 'gift', value $20. That is what I did. No duty, no tax.

[phillip08]

I am newer to this board. Not sure how this upgrade by passes the Arcam rdac. It looks like it just plugs into where the power cord would go? If so how does the internal power supply get by passed? If not do you have to open up the rdac?<br />

<br />

Thank you!!!

[Elberoth]

No need to open the rDAC. The Teddy PSU connects to the 6V input at the back of the DAC. It replaces the stock wall-wart PSU.

[phillip08]

Thank you Elberoth...So the rdac PSU is external?<br />

<br />

Based on your prior post its well worth the ~$200 upgragde? Would there be a DAC better or equal to the rdac + Teddy package at the ~$650 price?

[dizziness]

Which Teddy PSU in specific? Is it a specific model?

[lo1979]

Hoe<br />

[phillip08]

The model on TeddyPardo.com is rDac PS

[lo1979]

So how much did you pay including shipping cost??<br />

thanks

[Elberoth]

Here is the link to Teddy PSU:<br />

<br />

http://www.teddypardo.com/products/Powersupplies/rdacPS.html<br />

<br />

The PSU costs 248 euro shipped, which is around ~$300. It is well worth the money IMO, but (as always) will eventually depend on your system context.

[slgarris]

Everyone seems to rave about the PS Audio Digital Link III. I am curious if anyone has had a chance to compare the two. I am replacing my older Musical Fidelity X-DAC and want a true upgrade. Thanks!

[Schneider]

I have tried the Arcam rDac on a GNU/Linux x86 system and it works great without any trouble.<br />

<br />

I've also tried it on one of my plugcomputers Seagate Docstar wich I thought would be very cute for an MPD server.<br />

<img src="http://media.seagate.com/files/2010/08/FreeAgent_Go_silver_rightangle-300x300.jpg"></><br />

<br />

As for <a href="http://forums.slimdevices.com/showthread.php?p=612262#post612262">some users of Squeezebox</a> (linux and arm processors too), I was not able to make it sound on the Dockstar. The whole history is <a href="http://forum.doozan.com/read.php?2,4049">there</a> if you are interested in.<br />

<br />

So I may consider some other DAC.<br />

<br />

(I've already tried also the HRT II+ but with old firmware v1.4 that made the DAC stop playing due probably of too much usb consumption.)

[runeks]

Hi Schneider<br />

<br />

I'm very interested in asserting once and for all, whether Linux really is using the asynchronous USB transfer mode with this DAC. I'm wondering if you could do me a favor, and post the output of the below command when the DAC is connected to some Linux box? The command is:<br />

<br />

lsusb --verbose > usb-info.txt<br />

<br />

This will dump information to the file usb-info.txt, concerning USB devices connected to the system. It should state, among other things, if the synchronization used with the DAC is either "asynchronous", "adaptive" or "synchronous".<br />

<br />

If you do this, you could copy and paste the information from the file to, for example, pastebin.com, and post the link here.<br />

<br />

Thanks for your assistance!

[Schneider]

Hi Runeks,<br />

<br />

Unfortunally, I returned the Arcam rDac to the seller so I can't anymore execute the lsusb -v command.<br />

<br />

If I remember correctly, the output gave something like:<br />

<br />

Transfer Type: Isochronous<br />

Synch Type: Asynchronous<br />

<br />

The Arcam rDac is mentionned to work properly on various GNU/Linux systems as for example Olive 2 server.<br />

<br />

If it helps, here is some words I sent to the Arcam company:<br />

---------------------------------------------------------<br />

Dear Sir/Madam,<br />

<br />

I bought an Arcam rDac. But I can't manage to get sound through usb under linux Debian squeeze, alsa 1.023, kernel 2.6.37<br />

<br />

The rDac is well detected.<br />

<br />

usb 5-1: new full speed USB device using uhci_hcd and address 2<br />

usb 5-1: New USB device found, idVendor=0c56, idProduct=0002<br />

usb 5-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0<br />

usb 5-1: Product: ARCAM DAC<br />

usb 5-1: Manufacturer: ARCAM<br />

2:1:1: cannot get freq at ep 0x1<br />

<br />

root@debian:~# lsmod<br />

Module Size Used by<br />

snd_usb_audio 83873 0 <br />

snd_pcm 64363 1 snd_usb_audio<br />

snd_page_alloc 5443 1 snd_pcm<br />

snd_hwdep 4882 1 snd_usb_audio<br />

snd_usbmidi_lib 16519 1 snd_usb_audio<br />

snd_seq_midi 4302 0 <br />

snd_seq_midi_event 5410 1 snd_seq_midi<br />

snd_rawmidi 16336 2 snd_usbmidi_lib,snd_seq_midi<br />

snd_seq 45929 2 snd_seq_midi,snd_seq_midi_event<br />

snd_timer 17459 2 snd_pcm,snd_seq<br />

snd_seq_device 5591 3 snd_seq_midi,snd_rawmidi,snd_seq<br />

snd 43439 8 <br />

snd_usb_audio,snd_pcm,snd_hwdep,snd_usbmidi_lib,snd_rawmidi,snd_seq,snd_timer,snd_seq_device<br />

<br />

aplay -l<br />

**** List of PLAYBACK Hardware Devices ****<br />

card 2: DAC [ARCAM DAC], device 0: USB Audio [uSB Audio]<br />

Subdevices: 0/1<br />

Subdevice #0: subdevice #0<br />

<br />

aplay -D hw:2,0 test.wav gives:<br />

aplay: set_params:1053: Sample format non available<br />

Available formats:<br />

- S24_3LE<br />

<br />

and using: aplay -D plughw:2,0 test.wav gives:<br />

Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo<br />

underrun!!! (at least 0,010 ms long)<br />

underrun!!! (at least 0,013 ms long)<br />

underrun!!! (at least 0,006 ms long)...<br />

<br />

... and no sound<br />

---------------------------------------------------------<br />

<br />

Due to underun, I've compiled the latest alsa without success. So I sent the result of the utils_alsa-info.sh script to the alsa guys.<br />

<br />

But I have to say that my plugcomputer is a special ARM system.<br />

On a Desktop x86 GNU/Linux, the Arcam rDac worked great.<br />

<br />

I whish I could help more <br />

<br />

So now, I am wondering wich DAC I will connect to my Dockstar: probably HRT II+ with firmware >= v1.5 or I may try the <a href="http://www.lindemann-audio.de/en/products/small_utilities/usb-dac-24-192">Lindemann DAC</a> wich is a real usb audio class 2 device like the <a href="http://www.xmos.com/products/development-kits/usbaudio2">XMOS reference design board</a> (this one is a transport to spdif card but is <a href="http://www.head-fi.org/forum/thread/514211/best-mpd-setup/30#post_7148990">seen natively by the Dockstar up to 24/192</a>)<br />

<br />

<a href="http://img4.hostingpics.net/pics/446633usbdac24192frontlargemod.jpg"><img src="http://www.maison-passive-nice.fr/images/usb-dac-24-192_front.jpg" /> </a><br />

<a href="http://img4.hostingpics.net/pics/826747usbdac24192rearlargemod.jpg"><img src="http://www.maison-passive-nice.fr/images/usb-dac-24-192-rear.jpg" /> </a>

[runeks]

Hi Schneider<br />

<br />

Sounds good. You were just the only one I could find via Google that had tried the rDAC on Linux, so I figured I'd ask you. But if you've heard that it's working on Linux then that sounds good. The only thing I wondered about, is whether the chip in the DAC had some way of defaulting to non-asynchronous mode in case the OS doesn't support it. And if so, if it was this that was happening when it was plugged into Linux. I can't seem to get any confirmation that Linux support synchronous USB audio by Google searching. But again, it sounds like it does.<br />

<br />

Concerning the problem running the DAC from you ARM system; have you considered that the system just might be too slow to feed DAC through asynchronous USB? I would imagine that Seagate has equipped that Dockstar with a fairly slow CPU, and dedicated chips are taking care of all the high speed transferring of data. And as ALSA is running on the CPU, it might just be too slow to keep up with it.<br />

Have you tried playing some WAVE files at a lower sample rate/bit rate, to see if it can keep up with, for example, 8 kHz/8 bit WAVE? If it can, it would point towards a bottleneck in the system, rather than a bug.<br />

Or have you managed to play audio fine over the USB port from the Dockstar with other, non-asynchronous DACs? It *could* just be the Linux implementation of asynchronous USB audio syncing that's implemented in a way that is too slow to work on low end ARM CPUs. Have you tried loggin in to the device via SSH (howto: http://ahsoftware.de/dockstar/#backup) and seeing what kind of CPU it has (cat /proc/cpuinfo)?<br />

<br />

But thanks for that link to the Music Player Daemon thread! I had never heard of that program, but it seems to be exactly what I was looking for to put on a low power audio server, when I get to doing that. Has an Android app and everything, so it seems to be just what I need.