AK4499EQ - Best DAC ever

[syn08]

^^^
I am afraid that's not the root cause.

 

[scottjoplin]

Better just to say you haven't done any proper listening tests and be done with pointless arguing.

 

[andrea_mori]

^^^
I am afraid that's not the root cause.

In fact, I believe I should buy an FFT analyzer like yours to measure the jitter at the DAC output.

Can you provide brand and model?

 

[andrea_mori]

Better just to say you haven't done any proper listening tests and be done with pointless arguing.

And then I should use your ears to listen, mine are not suitable.

 

[syn08]

In fact, I believe I should buy an FFT analyzer like yours to measure the jitter at the DAC output.

Can you provide brand and model?

I believe you don't need one to support your findings, there's no business case to justify the expense.

 

[scottjoplin]

And then I should use your ears to listen, mine are not suitable.

That wouldn't help, mine are as fragile as yours.

 

[andrea_mori]

I believe you don't need one to support your findings, there's no business case to justify the expense.

Business is your problem and not mine.

 

[chris719]

If I'm not mistaken they're basically talking of a masking effect where low level signals get masked/buried by the widening of the base by lf phase noise of an adjacent stronger signal. Kind of like the average mp3 is defined.
Now if only we could calculate when this masking effect takes place and becomes detrimental to our perceived SQ.

For instance, is it true that a clock with a lf phase noise of -60dB at 1 Hz makes for a base -60dB wide at 99 and 101 Hz, if the high level signal of e.g. 0dB at 100Hz was taken?

I'd really like to know if that reasoning is correct, because to me this seems like a rather noisy signal.
Nothing at all like the free of rumble, hum and wobblefree digital source it supposedly should be.

And this happens when digitizing as well as when putting back to analog, so we're now hypothetically talking about -54 dB?

I am imagining my speakers being shaken -54dB on the rhythm of every signal it gets.

I think you’ve described the effect correctly but not the magnitude. Consider what would happen to the DNR if there is that much spreading into adjacent bins.

See: Analyzing and Managing the Impact of Supply Noise and Clock Jitter on High Speed DAC Phase Noise | Analog Devices

 

[mterbekke]

It gets funnier and funnier, so upconversion improves the sound. There must be a lot of information hidden from inquiring ears in that original 16bit/44.1KHz encoding.

Since this is the AK449EQ thread,

How do you think those 16 bits of PCM data get fed into the delta sigma modulator?

 

[chris719]

Since this is the AK449EQ thread,

How do you think those 16 bits of PCM data get fed into the delta sigma modulator?

All you and Mark need to say is that you are using HQPlayer to feed the DAC DSD in an attempt to "substitute" the sigma delta modulator inside the DAC with one implemented in software. This is much simpler than leading people into believing you are performing this conversion for other reasons.

Of course, this is of no real value, and how it works depends highly on what DAC chip you are feeding and how it handles DSD. We are already way off-topic and turning this into an HQPlayer BS thread probably isn't going to help.

 

[scott wurcer]

no equipment consistency or description

Don't forget:

But then I added the sand into the chassis, and the sound was elevated to a level beyond any other configuration.

 

[syn08]

^^^
You beat me in the patience required for reading such crap. I got to the point where I need not more than 1 second to decide what is worth spending the next 5 minutes and what is not.

https://www.diyaudio.com/forums/dig...itter-crystal-oscillator-185.html#post5887495

 

[scott wurcer]

If he looked hard I think the 12" cables that come with an HP calibration kit are $700 or so.

 

[syn08]

Poor me, I'm crimping my own RG-316 SMA cables at a total cost of about $5 a pop. Certainly not audiophile grade stuff.

 

[andrea_mori]

Poor me, I'm crimping my own RG-316 SMA cables at a total cost of about $5 a pop. Certainly not audiophile grade stuff.

But perfect cables for your stellar FFT analyzer with which you measure the phase noise.

Since mine are crappy, where are your designs (if any)?

 

[mterbekke]

I think you’ve described the effect correctly but not the magnitude. Consider what would happen to the DNR if there is that much spreading into adjacent bins.

See: Analyzing and Managing the Impact of Supply Noise and Clock Jitter on High Speed DAC Phase Noise | Analog Devices

Great article, thanks for that, it explains a lot.

So the relation of clock phase noise to signal phase noise is straightforward, like Frequency Clock = 10 times Freq Signal => N Signal = N Clock÷10 = -20dB.

If pcm Red Book format is being used, the F Signal and F Clock can be really close to one another (e.g. FSignal 10 KHz vs FClock 44K1, which would mean that the phase noise at that frequency is only 12.x dB lower than the clock's LF Phase Noise.

This shows that in order for all high frequencies, one should really take good care about the implementation, layout etc of the word clock for the dac chip. Iow I'm pretty sure a 7805 regulator could prove problematic, as would crosstalk etc.

Those should show up in bins, wouldn't they?

 

[Simon1972]

That could be viewed as both ignorant and offensive. I'll assume you didn't intend offense.

I'd just assume one would choose to go after the low hanging fruit which will make a differenc, as opposed to pouring funds into something so obviously on the edge of audibility.

Ymmv

 

[chris719]

Well, the clock isn't the frame clock in most cases (ex. 44.1 kHz). It's at least 8x that and more likely to be something like 11.2896 MHz in a sigma delta part.

It seems likely that if the phase noise were bad enough it would show up in a DFT.

 

[mterbekke]

"in an attempt to "substitute" the sigma delta modulator inside the DAC with one implemented in software".
.....
We are already way off-topic and turning this into an HQPlayer BS thread probably isn't going to help.

Hahahaha, so my response to Syn08's suggesting that PCM is what the converter core of this AKM dac needs, is someone who's off topic, yet your made up story about what you suspect I would have others believe isn't?

To boldly go where no man has gone before!

Insightful, thanks again.

But I have to give credit where credit's due. HQPlayer is indeed, as you were afraid of, the smartest way to feed this dac.

Thanks yet again, for bringing it up.

 

[mterbekke]

Well, the clock isn't the frame clock in most cases (ex. 44.1 kHz). It's at least 8x that and more likely to be something like 11.2896 MHz in a sigma delta part.

It seems likely that if the phase noise were bad enough it would show up in a DFT.

Well, yeah, but ranging from the a-typical NOS dac consumer all the way to HQPlayer, ahem, DSD256 recordings, worst case would be NOS.

Edit: to measure these, wouldn't one need the same measuring time (at least many minutes), as for the normal LF phase noise measurements?