Tweaker's Rash

[mjock3]

Nice links on post 54 for those using BBB: http://www.diyaudio.com/forums/twisted- ... nce-6.html

[Aleg]

if we wanted or felt it was necessary to add a separate master clock is it necessary/how do we sync the i2s to it

I don't think you can if you're not able to tap the original MCLK.
An additional masterclock board will IMHO always work asynchronously.

Otherwise it should be (made) possible to have the external masterclock board act as clock master and have both the DAC and the BBB be in slave mode to that external masterclock board.

I have not seen the possibility (didn't look for it) to have an external clock signal into the BBB. I have seen it is possible to switch off the internal oscillator, so that's already halfway there.

Need to delve al little more into the System Reference Manual of the BBB.

Cheers

Aleg

[Aleg]

if we wanted or felt it was necessary to add a separate master clock is it necessary/how do we sync the i2s to it

I have just had mail contact with DIYINHK and they can put on an onboard oscillator so you don't require an external masterclock or an external MCLK signal. Apparently in the design of the board they have foreseen this option. For testing purposes this is the simplest of solutions for me I think.

They put on an US$8.00 49.152MHz NDK ultra low phase noise oscillator: http://www.diyinhk.com/shop/audio-kits/ ... lator.html

I'll let you know when I get it.

Cheers

Aleg

[Aleg]

...
I think the clock may be available on P9 - pin25 in mode 2.

Cheers

Aleg

Apparently I was right about the location of the clock.
This posting confirms the availablity of the BBB clock on pin 25 from the P9 connector:
http://www.element14.com/community/comm ... ment-30089

It is only a 24.576 MHz clock though, so according to the ES9023 datasheet suitable only upto 96 kHz rample rate.

Cheers

Aleg

[jkeny]

...
I think the clock may be available on P9 - pin25 in mode 2.

Cheers

Aleg

Apparently I was right about the location of the clock.
This posting confirms the availablity of the BBB clock on pin 25 from the P9 connector:
http://www.element14.com/community/comm ... ment-30089

It is only a 24.576 MHz clock though, so according to the ES9023 datasheet suitable only upto 96 kHz rample rate.

Cheers

Aleg

If that's a synchronous clock then a masterclock of >192 fs doesn't apply & speeds above 96KHz can be handles by the ES9023 DAC chip? i.e

[Aleg]

...
I think the clock may be available on P9 - pin25 in mode 2.

Cheers

Aleg

Apparently I was right about the location of the clock.
This posting confirms the availablity of the BBB clock on pin 25 from the P9 connector:
http://www.element14.com/community/comm ... ment-30089

It is only a 24.576 MHz clock though, so according to the ES9023 datasheet suitable only upto 96 kHz rample rate.

Cheers

Aleg

If that's a synchronous clock then a masterclock of >192 fs doesn't apply & speeds above 96KHz can be handles by the ES9023 DAC chip? i.e

John

The ES9023 datasheet states:

MCLK
Asynchronous mode: MCLK must be > 192*fs.
Synchronous mode: Please see table below for supported configurations.

For best performance. 256fs or greater is recommended for 32kHz to 96kHz sampling.

So wouldn't this suggest at least 49.152MHz is required for best performance on 192kHz and the 24.576 MHz is supported but as a bare minimum?

Cheers

Aleg

[jkeny]

It will certainly handle 192Khz using a 24.576MHz synchronous clock & from my early experiments trying a 49.152MHz clock, "best performance" produced little or no SQ improvement @ 192KHz sample rates - but of course, there are many variables involved.

My real message is not to get too hung up on what the datasheet says. There is no doubt in my mind, for instance, that using a synchronous clock will show an audible improvement in the sound compared to using an asynchronous clock, irrespective of the clock speed used (this is something that isn't stated in the datasheet but even Dustin Forman?, one of the chief designers of the chip, admitted to on DIYA forum)

[tony]

Now I know why the vinyl heads eyes glaze over on Computer audio threads. But hoping a world beater with clear instructions for dorks emerges a very low cost.

[Aleg]

Now I know why the vinyl heads eyes glaze over on Computer audio threads. But hoping a world beater with clear instructions for dorks emerges a very low cost.

Patience Tony ;-)

I'm just collecting gear right now.
But I have confidence it won't be that difficult once a few people have gotten their head around it of what to connect to what and what sounds best.
The great thing is this basic stuff isn't that expensive either.

If I've got it running and it has a positive result on this basic gear, I'll probably go a step higher w.r.t. spec's of an I2S DAC and PSU.

I'm excited about the prospects.

Cheers

Aleg

[tony]

See MQn and Buildanaudiopc Aleg, I have the patience but it is technically on another level to anything done previously.
Looking forward to the results. A brief look on some other forums suggest this is being pursued on a fairly broad basis on diy sections. I wonder will bringing it to the zuma pc level be the biggest challenge but time will tell?

I will have to use my sons skills and interest in linux to get some handle on this stuff.