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The Asynchronous USB Audio class 2 module.

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Hi Russ

Great to hear you have found some proper hobby time to bring this project up to date.

If you are providing the option for off-boarding the Audio Master clock, a separate high performance master module with buffered outputs that could run both this device and the Buffalo might be a nice step up.

Thoughts?

Mark
 
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Joined 2007
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You could also use an ADC and use your PC as the DSP. :)

So many ideas, so little free time. :D

Very true! First things first... :)

I have no complaints about the quality of the crossover filters that are running in my PC. It just means 3 or 4 stereo USB boards unless an 8 channel version might be offered. ...much more elegant to delegate that job to later in the chain, IMVHO...

All the best for an energizing project, Russ!

Frank
 
May I ask one more?

I guess you must have found a definite advantage of TPS7A4700 comparing to your familiar LT1763 series regulators.
Have you made any fine tuning on the selection of bypass & NR caps used for the regs?

Honestly I need to evaluate it further, but on paper it has much lower noise, and better PSRR. I am happy with it so far.

I will be able to report my better tempered results soon. :)

I expect it will perform quite well. From a design perspective, it is a nice part to use because it is simple and easy to configure for multiple projects. It has a ton of up-side. I think TI did a nice job with this one.

Cheers!
Russ
 
Hi Russ

Great to hear you have found some proper hobby time to bring this project up to date.

If you are providing the option for off-boarding the Audio Master clock, a separate high performance master module with buffered outputs that could run both this device and the Buffalo might be a nice step up.

Thoughts?

Mark

Hi Mark - food for thought. But I think this particular module is useful in it's current incarnation.

Cheers!
Russ
 
Also...

Hi Mark - food for thought. But I think this particular module is useful in it's current incarnation.

Cheers!
Russ

Mark: I think what Russ is trying to say, is that there might be little to no advantage to incorporating an external master clock. Consider the way he has this board configured (at least as I understand it): the processor (XMOS) is on the USB side, and the (onboard) master clock is on the isolated/output side. the masterclock will be a very good, low phase noise, part, with a clean power supply isolated from the processor and USB noise. The data stream will be re-clocked, directly by the onboard clock, on the isolated/output side. And, master clock output will be available on a u.fl connector to directly clock the Buffalo DAC in synchronous mode. If you distribute the masterclock signal from the board to the B-IIIse via a short u.fl cable, and run the I2S lines on short u.fl cables, you should have sonic performance which is about as good as it gets, with jitter levels fully isolated from the source noise (computer/server) and the processor noise, without having to use the asynchronous sample rate converter onboard the Buffalo.
 
5. I2C control for DAC
Is the USB board configurable to send commands for setting registers in DAC over I2C?

Hi Russ,

I would love to have this capability, with the endgame objective to be able to utilise the volume control of the Buffalo (2) directly from within windows, without having to use an arduino or similar.

Really glad it's finally all coming together :D

Cheers,
Phil
 
This is interesting.

I'm looking to put together a multi amped "any speaker" PC setup.
That means all filtering handled by the PC, outputted by USB (8 channels), converted to I2S, feeding a Buffalo3.
Then 8 channels of amplification (a pair of sureelectronic 4x100W tk2050 is a likely candidate).
I figure with that setup, I can get any drivers I like, put them in a box and make them work properly in room with minimal effort.

I hope you don't mind me mentioning this here, but since TPA have such good rep here I don't think it will hurt you. I was looking at the USBStreamer to do the USB-I2S bit, will your board be able to manage it?
I have a lot of respect for your work, and going all TPA sounds preferable if it would work
 
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