Okto dac8 stereo DAC Review

[pozz]

Reminded me of this... -129dB THD+N
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Just for reference: https://www.uaudio.com/audio-interfaces/apollo-x16.html

 

[pozz]

Well now coming back to the original question. Half of the question is answered. The DAC's noise performance is easily better than the AP's output.
The other half is that dynamic range is low at 127dB instead of 131dB from spec. I would like to know if anyone can help to reproduce the spec.

Isn't it answered in the same way? Their spect SNR is better cause Okto subtracted the analyzer's noise?

 

[Thomas savage]

So nice to read!
This very DAC, Pavel and his colleagues were here:
https://www.sunshipaudio.com/2020/02/okto-dac8-stereo.html
Great DAC, great people.
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@watchnerd look at these bud.

 

[Thomas savage]

Well 80% of the times you accuse intelligent people of being me it's not me. But I'm glad my plan for the forum works after a couple years of failure!

https://www.audiosciencereview.com/...can-we-make-audio-science-review-forum-1.218/

 

[watchnerd]

@watchnerd look at these bud.

Oh those speakers look sweet.

And TAD drivers!!!!

How ridiculously are they priced?

 

[bobbooo]

Two hour suite though? That doesn’t sound too practical. Like imagine that on top of something like a 30 minute thermal test.

There’s also the issue of needing to get liscence free music, on top of opening yourself up to critique about music selection.

Again, the test itself doesn’t strike me as something unsound, but as you can see, noise of 1-2db of difference is hardly something I think is worth exploring beyond recognition of its existence for said device. I imagine a difference of something like 2db is seemingly only an issue with respect to final output through headphones or speakers that distort far worse than any modern DAC. A 2db diff between something like 120db SINAD and 122db SINAD seems uneventful in the least even if such diff manifests in the first place using non coherence as a metric.

Also, at these levels with the AP pushed to its limits, I imagine breathing (metaphorically speaking) over the devices as they run - would have an impact.

You’d also have to be careful on measuring noise separately (unless I misunderstand non coherent distortions).

So again, I’m just not seeing the value. Great for theoretics, and for someone that really wants to dig deeper. And possibly a test suitable if he never transitioned to testing speakers (though I’d say possibly better for speaker testing), but in reviews where I have to bug him to run Toslink measurements, SINAD over Power level, or SINAD over time, or just filter performance. I doubt this is something Amir would run. The work itself isn’t daunting as you can just create a single file of the entire suite, the time required is the problem.

I'm not proposing to use the full 2-hour test suite, for the vey reasons you mention. I'm proposing to use the already standardized and widely used BS EN 50332-1 'Program Simulation Noise' test signal (described toward the bottom of this page), which was originally devised to have spectral content representative of music and speech for testing audio devices. This test signal is just 30 seconds long. As I said, SoundExpert's previous measurements have shown the null difference metric using this program simulation noise to be consistently just ~1-2 dB higher (worse) than the same metric calculated using the 2-hour real music suite, over all devices tested (45 so far), and using different ADCs. This is strong evidence that the program simulation noise would make an ideal analogue to worst-case real music (i.e. music that would produce the worst distortion through the DUT) to use in the null difference measurements instead of the 2-hour test suite. So that's just a 30-second recording and a few mouse clicks in the software to measure all possible sound degradation of any part of the electronic audio reproduction chain. I can't think of a quicker, easier measurement with as much utility as that. Well worth a try at least I reckon. (The non-coherent distortion metric mentioned in the video I linked isn't directly related to null difference measurements by the way - I just mentioned it as it also uses music as the test signal, and to demonstrate that the standard multitone test is poorly correlated to sound quality.)

I see there are several owners of an APx555(B) in this thread - would any of you be willing to try out these null difference measurements using your AP analyzers? Preferably recording a device already measured here on ASR so correlations with SINAD can be made, but any data would be useful. A loopback null test would also be interesting to see the upper limit of the APx555 in terms of the null difference metric.

 

[watchnerd]

@watchnerd look at these bud.

Okay, price...

58,000 euros....

 

[Thomas savage]

Okay, price...

58,000 euros....

That's a lot for what looks like a Rel subwoofer on its side with a few holes bored out and a bit of 9th grade wood work on top.

Difficult to un-see now though, they are quite cool looking.

 

[Vasr]

I see there are several owners of an APx555(B) in this thread - would any of you be willing to try out these null difference measurements using your AP analyzers? Preferably recording a device already measured here on ASR so correlations with SINAD can be made, but any data would be useful. A loopback null test would also be interesting to see the upper limit of the APx555 in terms of the null difference metric.

You may get more of an interest if you can start a new thread with the information you have posted here starting with what you would like to be done (call for action) stated as simply as possible independent of the rationale for it and THEN give the rationale and supporting material as a separate post for those that want to dive deeper. I am not sure everyone necessarily reads this therad especially after 18 pages of it. Just a suggestion.

 

[Feyire]

Thanks @Okto Research/Pavel. DAC8 Stereo owner reporting in :

 

[EchoChamber]

Owner reporting in :

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Wow!! This is awesome!!! I will be you in a month or so... :-D

 

[EchoChamber]

Owner reporting in :

View attachment 73588

That front plate is much thicker than I thought it would be... Nice!

 

[bennetng]

Just for reference: https://www.uaudio.com/audio-interfaces/apollo-x16.html

Yes. Multichannel thunderbolt interface with hardware DSP.
Slightly more features than a phone dongle + atom I suppose.

 

[Feyire]

The DAC doesn't come with its own power cable, would've been nice if this was explicitly mentioned somewhere (prior to ordering).

 

[EchoChamber]

Okay, price...

58,000 euros....

There goes my Tesla...

I find those horn speakers breathtaking. Craftsmanship is pure perfection. If they sound as good as they look, some might be willing to pay for them.

Could Amir get a pair for testing? It would be probably cheaper to travel to Berlin with the testing gear and test them there.

 

[Labjr]

Just for reference: https://www.uaudio.com/audio-interfaces/apollo-x16.html

Advertised specs don't mean anything. They don't reveal which DAC chips are they using. Maybe using one DAC IC for multiple channels.

 

[digititus]

Most people on this forum don’t realize this

Son, you must be new here.

 

[pozz]

Advertised specs don't mean anything. They don't reveal which DAC chips are they using. Maybe using one DAC IC for multiple channels.

It's a pro company. If RME can deliver, I don't see why others can't.

I'd like to see test reports before taking them seriously, of course.

 

[amygdala_angst]

Moved post to more relevant thread (#27).

 

[bennetng]

It's a pro company. If RME can deliver, I don't see why others can't.

I'd like to see test reports before taking them seriously, of course.

I've only seen RMAA analog loopback of the lower-end x6 with weaker specs:
https://www.audiosciencereview.com/...apollo-x16claims-129db-thd-n.4434/post-145412

x6 specs: