Open-source USB interface: Audio Widget

[starn02]

Originally Posted by borges

Hi Starn02,

could you please try the track from my post 748 with the newest firmware? I was having some problems with that today, but didn't have the time to finish debugging. It would be interesting to see if it plays flawlessly and with correct word clock on other people's systems.

Børge

I can confirm that on my Win XP with UAC2 everything is OK! I tested with the file you indicated.
Perfect reproduction at 96 and 192k. Also fast forward and rewind work flawlessly at any rate (always in foobar 2000 1.1.10).

I can also add that:
- my PC is actually a 11" notebook from Acer, with ULV CPU, so no much horsepower here, but the CPU stays at 2 - 6% even when upsampling
- everything was ok even with a 800KBPS download from 2L in background ...

Even if you switch on and off the resampler while playing there are no strange noises, only a very small silence (0,1 sec) and then music again. Perfect.

[oneoclock]

Originally Posted by borges

Hi John,

Try removing R26 and feed your +5V to pin 2 of J5. Then your supply powers the entire Audio Widget.

Alternatively, remove L2 and put your supply to the + pin of C21 to power the DAC. Or remove L1 and put your supply to the + pin of C31 to power the XOs. These two may be combined.

There are numerous I2S to SPDIF converter chips. You'll have to patch such a device onto the analog board or module. This should be fairly doable, the largest challenge probably being the pinout and control of the converter chip.

Børge

I want only replace power supply AVCC and VCC-XO.

If you remove L2 and put supply to pin C21 you do external power analog DAC supply.
If you remove L1 and put supply to pin C31 you do external power clock supply.
Yes, but through ADP151 regulators.

Remove R23 and put supply to connector J4 analog DAC supply.
Remove R22 and put supply to connector J3 clock supply.
This put power supply to DAC and clock without through ADP151 regulators.

What is the function of pin 3 EN ADP151 regulators?
What is the function of J2 J3 and J4 connectors?

I think that putting 3.3 V. on connector J2 ADP151 regulators off (ADP151 EN pin 3).

And you can put external power supply to J3 and J4 without desoldering components R22 and R23, or L1 and L2. And without through ADP151 regulators. It's easier.

Thank you very much for your help.

[sampler]

Originally Posted by 1audio

The Windows problem is lack of an opensource driver. Perhaps we could "package" a Linux player and small Linux distro so that it could run in a virtual box inside Windows. The big roadblock would be whether Windows would get in the way of the hardware access. Otherwise it may be possible to package a mini Voyage MPD in a way that it would run inside Windows as a virtual session. The UI would still be on the Windows side.

That's exactly my thoughts too, but from lack of responses it's seems no one has tried that yet. Theoretically this sounds doable and would enable at least some uac2 support for higher sample rates without hacking 3d parity drivers of other vendors. Borges, UnixMan, anyone ?

[borges]

Hi Oneclock,

The EN pin is to enable/disable the regulators. It will play a role for USB power down. It is called VBUS_EN because it determines wheter or not additional points of load from VBUS may be in use.

J2 is a future upgrade power sense by which the MCU may learn something about an external power. It is connected to an ADC pin of the MCU.

J3 and J4 are for bypassing the ADP151s. Or for tapping their output to whatever you choose to patch onto the board. Remove R22, R23, respectively, for bypass.


Børge

[borges]

Hi guys,

I'm sensing the same kinds of thoughs on a lot of different channels here: screw the driver, let's make a VM. This we can do!

I'm all for it! There is much more Linux knowledge than Windows knowledge in our group. Here are some loose thoughts. Let's bring out our ideas first before we start cutting them down. Do pardon my lack of proper lingo...

- Which VMs are available with sensible licenses?
- Will a VM forward a raw USB port not supported by the host OS?
- A "driver" should be split in multiple parts/layers to make it portable and
spread out our efforts
- UAC2 hardware interface on (realtime?) stripped-down Linux kernel
- Target "HW" is VM on host, lowcost Linux box in stereo kit, eventually
Android phone
- GUI over httpd to put it on browser or player plugin
- GUI may be pyisically separate from player kernel
- Audio data over streaming or mounted fs
- Player program(s) installable and accessible through X/ssh
- We might even make a Windows ASIO driver which talks to the VM :-)

I want to hear your ideas too before we start eliminating and straightening things out!


Børge

[oneoclock]

Originally Posted by UnixMan

I see two different pictures with the exact same label... what's the difference between the two?

What I made ​​is two types of details in the measurements. One covers 20 to 20 kHz and another one of 9 kHz to 13 kHz. The label is program and settings used.

The J-test signal is Explained here:
http://www.nanophon.com/audio/diagnose.pdf

I use J-test 44.1 khz. 16 bit. It is a tone of 11 kHz at -3 dBFS over a square wave of 1 bit to 229 hz with many harmonics.

The best measure of Jtest that I have is Hiface Buffalo DAC and has an analog output + 3 dBu in the spectrum analyzer.

In absolute values ​​for hiface images should have a scale of 6 dB less.

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.

Jtest: Hiface+ Buffalo DAC

AB-1.1 has output + 5 dBu. It should come down 8 dB to absolute values.

[borges]

Hi Oneclock,

interesting stuff! What is the analyzer you're using?

In your opinion, is this good or bad? I'm new to Jtest.

Børge

[oneoclock]

AB-1.1exceptional measures. In AM700 Tektronix spectrum analyzer similar measures to Benchmark DAC1 USB and Hiface + Buffalo USB DAC.

All DAC I measure, have many differences in quality between programs with default setings.

This DAC with proper program settings, all programs measures identically, as well as Hiface work. It works really asynchronous.

In other DAC, is always very big differences one program to other in quality when the clock is provided by the PC and there are only DAC PLL clock.

[borges]

I'm glad we're on the right track :-)

Happy New Year to you all!

Børge

[johnm]

I've attached an external 5v supply to J5. Nothing exotic just a Black Gate 1000uF 50v cap before and after a 7805 OnSemi regulator. MUR860 rectifying diodes. Too early to tell yet if it's made a day and night difference - need to dosome serious listening tomorrow. It's allstill working fine however and doesn't sound any worse

A very Happy New Year to you all folks

John