Schneider

I had benefits when adding an USB 5V linear power supply on an April Stello U3. I had also improvements with dedicating a linux based computer as a music server. There is very few words about OS except dCS wich says: " In the long run, Linux-based music servers have incredible potential as they can be customized to do nothing more than play audio "

Extracts: !!Soundcards recognised by ALSA !!----------------------------- 0 [M20 ]: USB-Audio - M2Tech USB Audio 2.0 M2Tech M2Tech USB Audio 2.0 at usb-0000:00:1a.7-3, high speed !!Loaded sound module options !!-------------------------- !!Module: snd_usb_audio async_unlink : Y device_setup : 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 enable : Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y id : (null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null) ignore_ctl_error : N index : -2,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 nrpacks : 8 pid : -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 vid : -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 !!USB Mixer information !!--------------------------- --startcollapse-- USB Mixer: usb_id=0x249c930b, ctrlif=0, ctlerr=0 Card: M2Tech M2Tech USB Audio 2.0 at usb-0000:00:1a.7-3, high speed Unit: 10 Control: name="M2Tech Clock Selector Playback Volume", index=1 Info: id=10, control=2, cmask=0x0, channels=1, type="S16" Volume: min=-32512, max=0, dBmin=-12700, dBmax=0 Unit: 10 Control: name="M2Tech Clock Selector Playback Volume", index=0 Info: id=10, control=2, cmask=0x3, channels=2, type="S16" Volume: min=-32512, max=0, dBmin=-12700, dBmax=0 Unit: 10 Control: name="M2Tech Clock Selector Playback Switch", index=1 Info: id=10, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 10 Control: name="M2Tech Clock Selector Playback Switch", index=0 Info: id=10, control=1, cmask=0x3, channels=2, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 --endcollapse-- !!-------Mixer controls for card 0 [M20] Card hw:0 'M20'/'M2Tech M2Tech USB Audio 2.0 at usb-0000:00:1a.7-3, high speed' Mixer name : 'USB Mixer' Components : 'USB249c:930b' Controls : 4 Simple ctrls : 2 Simple mixer control 'M2Tech Clock Selector',0 Capabilities: pvolume pswitch penum Playback channels: Front Left - Front Right Limits: Playback 0 - 127 Mono: Front Left: Playback 127 [100%] [0.00dB] [off] Front Right: Playback 127 [100%] [0.00dB] [off] Simple mixer control 'M2Tech Clock Selector',1 Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum Playback channels: Mono Limits: Playback 0 - 127 Mono: Playback 127 [100%] [0.00dB] [off] So for an MPD installation, the alsa section should be: audio_output { type "alsa" name "M2tech Hiface Two" auto_resample "no" # important device "hw:0,0" # format "44100:16:2" # important: line to be commented mixer_type "hardware" mixer_device "hw:0" mixer_control "M2Tech Clock Selector" mixer_index "1" }

With a little plugcomputer or similar, you can have something really convincing: GoFlex Net + 24 bits / 192 Khz usb transport (April Stello U3) + V-Dac II + Android smartphone or iPhone. Here is one of my systems with a v-Dac I:

The drivers for Windows are out on the M2tech website. And, as presumed, the USB chip is an XMOS, so natively supported under Linux and OsX.

So did you get your Stello U3? And what have you decided for the DAC? Metrum Octave or Audiolab M-Dac? I am also considering changing my V-Dac to something better: Musical Fidelity M1, Metrum Octave or Rega Dac. So I'm expecting to read your choice and your impressions.

Glad to read that. :-) For the DAC, maybe you can have a look at XMOS based DAC or Transport: DAC USB Audio Class 2.0 (supported in Linux since kernel 2.6.36) - Ayre QB-9 (XMOS) - April Eximus (XMOS) - Grace Design m903 (XMOS) - Debussy dCS (XMOS) - Lindemann DAC (XMOS) - Calyx DAC, (XMOS) - IZO IHA 21 DAC (XMOS) - Meitner Audio MA1 (XMOS) - Ratoc Audio Lab RAL-24192UT1 (XMOS) - PhaseTech USB-DAC HD-7A192 & USB-DDC HD-7D192 (XMOS) - Bladelius USB DAC(XMOS) - CYP AU-D160 Cypress Technology Co Ltd (XMOS) or Tenor 8802 based - Firestone ILTW (Tenor 8802) - Teac UD-H01 (Tenor 8802) Transport USB Audio class 2 - Wavelength Wavelink HS 24/192 (XMOS) - April Music Stello U3 (XMOS) ** I have one and I really enjoy ** - Lindemann USB DDC 24/192 (Tenor 8802) - announced Musical Fidelity V-Link 192 (probably XMOS based)

I've been asked to explain how I've set the Dockstar to boot by tftp. So on the client Dockstar (that runs MPD): # /usr/sbin/fw_printenv ethact=egiga0 bootdelay=3 baudrate=115200 mainlineLinux=yes console=ttyS0,115200 led_init=green blinking led_exit=green off led_error=orange blinking mtdparts=mtdparts=orion_nand:1M(u-boot),4M(uImage),32M(rootfs),-(data) mtdids=nand0=orion_nand partition=nand0,2 stdin=serial stdout=serial stderr=serial rescue_set_bootargs=setenv bootargs console=$console ubi.mtd=2 root=ubi0:rootfs ro rootfstype=ubifs $mtdparts $rescue_custom_params rescue_bootcmd=if test $rescue_installed -eq 1; then run rescue_set_bootargs; nand read.e 0x800000 0x100000 0x400000; bootm 0x800000; else run pogo_bootcmd; fi pogo_bootcmd=if fsload uboot-original-mtd0.kwb; then go 0x800200; fi force_rescue=0 force_rescue_bootcmd=if test $force_rescue -eq 1 || ext2load usb 0:1 0x1700000 /rescueme 1 || fatload usb 0:1 0x1700000 /rescueme.txt 1; then run rescue_bootcmd; fi ubifs_mtd=3 ubifs_set_bootargs=setenv bootargs console=$console ubi.mtd=$ubifs_mtd root=ubi0:rootfs rootfstype=ubifs $mtdparts $ubifs_custom_params ubifs_bootcmd=run ubifs_set_bootargs; if ubi part data && ubifsmount rootfs && ubifsload 0x800000 /boot/uImage && ubifsload 0x1100000 /boot/uInitrd; then bootm 0x800000 0x1100000; fi usb_scan=usb_scan_done=0;for scan in $usb_scan_list; do run usb_scan_$scan; if test $usb_scan_done -eq 0 && ext2load usb $usb 0x800000 /boot/uImage 1; then usb_scan_done=1; echo "Found bootable drive on usb $usb"; setenv usb_device $usb; setenv usb_root /dev/$dev; fi; done usb_scan_list=1 2 3 4 usb_scan_1=usb=0:1 dev=sda1 usb_scan_2=usb=1:1 dev=sdb1 usb_scan_3=usb=2:1 dev=sdc1 usb_scan_4=usb=3:1 dev=sdd1 usb_init=run usb_scan usb_rootdelay=10 usb_set_bootargs=setenv bootargs console=$console root=$usb_root rootdelay=$usb_rootdelay rootfstype=$usb_rootfstype $mtdparts $usb_custom_params usb_bootcmd=run usb_init; run usb_set_bootargs; run usb_boot usb_boot=mw 0x800000 0 1; ext2load usb $usb_device 0x800000 /boot/uImage; if ext2load usb $usb_device 0x1100000 /boot/uInitrd; then bootm 0x800000 0x1100000; else bootm 0x800000; fi ethaddr=00:10:75:1A:CB:F6 arcNumber=2097 usb_rootfstype=ext3 usb_root=/dev/sda2 usb_device=0:2 rescue_installed=1 *** NET section *** net_bootargs=root=/dev/nfs rw serverip=192.168.2.10 *** address of the tftp server *** ipaddr=192.168.2.50 *** address of the client *** bootargs_end=:::DB88FXX81:eth0:none mvNetConfig=mv_net_config=(00:10:75:1A:CB:F6,0:1:2:3),mtu=1500 *** mac address of the client *** mvPhoneConfig=mv_phone_config=dev0:fxs,dev1:fxs net_bootcmd=tftpboot 0x2000000 $net_image_name;setenv bootargs $console $net_bootargs nfsroot=$serverip:$net_rootpath ip=$ipaddr:$serverip$bootargs_end $mvNetConfig $mvPhoneConfig; bootm 0x2000000; bootcmd=usb start; run force_rescue_bootcmd; run ubifs_bootcmd; run usb_bootcmd; usb stop; run net_bootcmd; run rescue_bootcmd; run pogo_bootcmd; reset net_rootpath=/srv/tftp/ *** linux system on the tftp server *** net_image_name=/boot/uImage *** uImage name for client Dockstar /boot " To install Archlinux: - download the file here for the system: http://archlinuxarm.org/os/index.php?d=armv5te/ that you will uncompress on the tftp server /srv/tftp - boot your Dockstar client on the network. Updade Pacman and ugrade. Do not reboot. - download and update files for the kernel modules and uImage located here: http://216.146.103.100/sheeva/3/3.0/3.0.7/. Uncompress them to be here on the client: /lib/modules/x.x.x (I use 3.0.7) and there: /boot/uImage Enjoy ;-)

I made my little, fanless, MPD music server with GNU/linux on ARM architecture. I had also to make one of this little ARM computer a NAS. http://www.computeraudiophile.com/content/April-Stello-U3-V-dac-MPD-linux-greatly-pleased

Thank you for the link. So exit the Guruplug. The Dockstars do not have this issue. The AC power adapter is external. May the DreamPlug has a better design than the Guruplug ?

Improvement. Now there is no more usb boot key on the mpd server. The usb port is completely dedicated to the April Stello U3. How ? This Dockstar boots on the network by tftp and runs Archlinux. I've played 96 kHz flac files (Brahms by Murray Perahia) and it takes a little 5% processor time.

I have not yet tidy so don't blame me, but it's how it looks like: Click to enlarge

The plugcomputers are Dockstar: one as a NAS, the other as the MPD server The NAS Docktar (nfs, webdavs) runs Debian on the USB disk, has a WiFi usb key and is connected via Gigabit to the MPD Dockstar The MPD server Dockstar The MPD Dockstar has a 4Go USB key that runs Debian without swap and no logs. This part is important for there is only I/O on the usb port that connects to the Stello U3. The mpd server has its own log, pid and database files on the distant NFS. The April Music Stello U3 The V-dac All the collection (classical mainly and jazz) is accessible via WiFi on every computer or with an iphone/ipad/ipod touch/Android smartphone... The guruplug server might be a very good solution, all in one, it has - one usb port for the usb transport (here Stello U3). This one should not be shared. - an e-SATA port for both the MPD server, the music files. And of course, you can add various servers: samba, nfs, webdav... - a Wifi interface, so no matter where is located your amplifier - and extra gigabit interfaces

This post just to tell that I am very pleased with this combination: - dedicated music server (mpd) on a Linux plugcomputer - nas where I store all my flac files on a Linux plugcomputer - April Music Stello U3 async USB audio class 2.0 24 bits /192 Khz, a wonderfull made transport that respects standards (USB audio class 1.0 & 2.0) Bus 001 Device 003: ID 20b1:0002 XMOS Ltd **** List of PLAYBACK Hardware Devices **** card 0: X20 [XMOS USB Audio 2.0], device 0: USB Audio [uSB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 - USB Ultraviolet cable - Musical fidelity V-dac For all Mac/Linux users, because these OS implement USB audio Class 2.0, I think the Stello U3 has to be considered. It is based on XMOS chipset as the Wavelength and has full galvanic isolation. What surprises me really, when I compare to my old CEC CD player, is the depth and width of the stage.

In Switzerland, ABC PCB produces an USB Audio Class 2 card based on XMOS chipset, called Edel USB to I2S/SPDIF. It has full galvanic isolation and a flex connector that accepts BNC, RCA in standard. The datasheet is here. USB Audio Class 2 permits to play natively 24 bits/192 kHz files on MacOsX >= v10.6.4 and recent Linux distributions. It requires a driver for every Windows versions. This one is currently in development. But you can still use the card under Windows with USB audio Class 1 (switch on board). Prices : April 2011

Thank you for the links.<br /> <br /> <cite>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. </cite><br /> <br /> The Dockstar is powerfull enough to play FLAC files and takes only 4% of the processor time <br /> With HRT II+ async DAC, it should go well if the firmware >= v1.5. I've tried with a v1.4 firmware model: everything went good except the DAC energy consumption via USB (a known bug with this firmware).<br /> <br /> As I said, the Arcam rDac plays without any trouble on x86 Linux.