Async USB Dac Experiments - testers wanted...

[praganj]

Highly interesting thread, thanks for all developpers work

Does anybody knows if SBT with kernel updates will work with M2tech hiface ?

[Phil Leigh]

Highly interesting thread, thanks for all developpers work

Does anybody knows if SBT with kernel updates will work with M2tech hiface ?

The last thing you want to do is to connect a USB-S/pdif interface to the Touch! The existing s/pdif on the Touch will outperform that.

The point of this thread is to get async USB working so that an ASYNC DAC can be connected via USB to the Touch, minimising jitter. Putting s/pdif back into the setup does not minimise jitter!

[praganj]

The last thing you want to do is to connect a USB-S/pdif interface to the Touch! The existing s/pdif on the Touch will outperform that.

The point of this thread is to get async USB working so that an ASYNC DAC can be connected via USB to the Touch, minimising jitter. Putting s/pdif back into the setup does not minimise jitter!

I understand. I have Buffalo II DAC (i want to keep it definetely), which has i2s input. It means that i need one usb-i2s converter working with tweaked SBT. Twisted Pear announced something like that, but it is still not available.

Any recommendations ?

[Triode]

I've tried USB audio 0.3 (I hope that's the right one) and it still doesn't work with my 2706 based DAC. It just continuously reboots.

John - I found a bug in the 0.3 version of USB Audio Output - could you try updating to 0.4 and trying again with your 16 bit dac? (Ideally also try the new #3 kernel with the dac too so I know it supports these dacs)

[JohnSwenson]

Highly interesting thread, thanks for all developpers work

Does anybody knows if SBT with kernel updates will work with M2tech hiface ?

It definitely does NOT. The Hiface uses it's own proprietary USB protocol which requires its own special driver. There is no linux version of this driver so there is NO WAY it can run on the Touch. With Triode's recent efforts the Touch can support pretty much anything that uses one of the official USB audio class modes, but not if it will only run with it's own proprietary driver.

John S.

[JohnSwenson]

John - I found a bug in the 0.3 version of USB Audio Output - could you try updating to 0.4 and trying again with your 16 bit dac? (Ideally also try the new #3 kernel with the dac too so I know it supports these dacs)

I'll give that a try today. I'm also going to try the EMU-0404 which run in HS mode but has it's own protocol. ALSA put support for this in the USB driver quite a while back so I'll check and see if it works with the kernel 3.

I really need to get my udev stuff over to you. This keeps the devices in the right order when you have a USB DAC plugged. Hopefully you could install that with the USB audio applet.

Thanks,

John S.

[dsdreamer]

Okay, I haven't been paying attention to what's been happening in Squeezebox land for a while, just listening to my music as often as I can via my SB Touch. So today, I come across this thread and on a whim and decide to try it out. I really don't have any nice USB DACs but I did try this with a REGA DAC, which has a "convenience" USB interface limited to 48kHz and 16 bits. Well this worked fine with kernel #3. Next I borrowed my son's NuForce Icon uDAC-2 and that worked straight away as well, at least for 44.1/16 audio.

The ridiculous thing is that the NuForce is sounding better than the REGA when connected this way to my ears.

Of course the real value of doing this comes Asynchronous USB. I am thinking NuForce does a special edition of their Icon uDAC-2 with Asynchronous USB for $250...I'm pretty tempted right now.

I must say, triode, you've blazed a very useful trail here. Many thanks for the hard work it must have taken!

[JohnSwenson]

John - I found a bug in the 0.3 version of USB Audio Output - could you try updating to 0.4 and trying again with your 16 bit dac? (Ideally also try the new #3 kernel with the dac too so I know it supports these dacs)

Hi Triode,
I tried the new USB audio applet 0.4, with the default kernel, it works great with both the HRT streamerII (async class 1.0) and the 2706 (adaptive, 16 bit class 1) based DAC. The 2706 DAC works at all sample rates (44.1, 48, 88.2 and 96) which is a bit unusual since its only supporting up to 48. So either its using plug, or the server is resampling. I checked the info while it was playing different sample rates, and its just playing 44.1 or 48. I thought your jive_alsa was doing hw not plug so I'm not sure what is going on here.

I tried kernel 3 and got exactly the same results. In addition I also tried the EMU-0404, which works in 44.1 but has bizarre sound in higher rates. So it looks like the EMU-0404 specific code did not make it into this kernel. I do not have any class 2.0 DACs to try at this point.

We'll have to let someone else try a class 2.0 DAC.

Great job on this, it really is working well now.

John S.

[Isflicka]

Known working device:
- Audiolab M-DAC (USB audio class 1) with external high speed hub

- Audiolab M-DAC without USB hub kernel #1, kernel #2 and kernel #3 no problem at all

[tufty]

Audiolab 8200CDQ _not_ working with kernel #3 and no hub.

Given that I have practically no hi-res material, are there any other benefits to going the hub route?