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Okto dac8 stereo DAC Review

bennetng

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I already did a while ago. Couldn't find the files, so I just did it again, literally takes a couple of minutes. Loopback Df value of my PC's Realtek HD Audio soundcard using DeltaWave:

View attachment 73947
FYI:
https://www.audiosciencereview.com/...-adi-2-pro-fs-black-edition.10834/post-303239
https://www.audiosciencereview.com/...-of-amp-and-dac-measurements.5734/post-309900

I am not going to comment about DF Metric but you can download a lot of loopback recordings from gearslutz and analyze them using whatever method you like. Of course, if you use deltawave, better ask pkane when there are questions.
 

Sal1950

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Extremely impressive SOTA performance and at a very affordable price, it doesn't get better than this.
One again ASR has revealed a world class product at pricing the layman can afford.
The 8 channel model is a answered prayer for the DIY multich enthusiast again at a bargin price
I don't know how Okto does it but major kudo's to them for the results!
And thanks to Amir for showing the High Fidelity world that just about anyone can afford the very best.
Sal
 
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Billy Budapest

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They banned this user. A big troll, that dude that has an ego the size of California, think is a genius but can’t assemble his own products. He can’t even solder wires correctly. It’s comical but tragic because his dacs are a danger to his customers (and their families and neighbors). Amir fixed a bunch of those trash dacs.
Do we know for sure this is the same dude who keeps joining under different names?

I checked out his website and it is weird—you have to pay to become a member of his “club” and then you can purchase his DACs. Not sure where he came up with that marketing strategy.
 

EchoChamber

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Do we know for sure this is the same dude who keeps joining under different names?

I checked out his website and it is weird—you have to pay to become a member of his “club” and then you can purchase his DACs. Not sure where he came up with that marketing strategy.
I'm not sure it is him, but that was the general conclusion from seasoned ASR members. I took a 10 year break from all audio forums, I'm just getting back to it this year (I'm glad I found ASR) so I'm not familiar with this dude's full history. But if you look at his writing style and what comes out of his keyboard, there’s a big resemblance.

Yeah, his site seems like a big scam to me. Paying in advance for a product that doesn't exist surrounded by superlatives sounds like a really bad investment. No proof of concept, and looking at previously released DACs where wires were poorly soldered plus all the poor layout and unsafe practices is scary... I wonder what the Better Business Bureau or Consumer Reports would think of it.

I think we should ignore him though (not mention his name, company or replying to his provocations), we're giving him too much attention, and I feel that is his sole goal for trolling ASR. Only use his example as something to be very cautious about and protect ourselves from similar practices.
 
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Kal Rubinson

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I checked out his website and it is weird—you have to pay to become a member of his “club” and then you can purchase his DACs. Not sure where he came up with that marketing strategy.
He didn't invent it. There used to be brick-and-mortar shops that demanded a non-refundable deposit before any demos or discussions. The deposit would be applied to any subsequent purchase. Not missed.
 

bobbooo

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Loopback? You need to play music, capture it, and then do the comparison. And since folks would want to know about the files, you need to upload them to some site and provide links.

As it is, I am not sure how would care about the graph you post.
Yes, it was a loopback null difference measurement, as in the difference signal between my soundcard's DA/AD loop output as a ratio of the original signal, just like these measurements. Obviously this is the first thing needed to be done in order to see what the limits of the recording equipment are. And yes this was using the capture and difference measurement of music, the same track that was used in the above link of Df measurements, for ease of comparison with other devices in that list, and which I have already linked to in a previous comment. Here it is once again:

https://www.dropbox.com/s/yqr9tm9rzhua1k9/Original2.wav

And for those who have an AP Analyzer, again as I linked previously, the standardized (and preferred) BS EN 50332-1 'Program Simulation Noise' test signal, representative of the spectral content of music and speech, can be downloaded and used instead, as part of their audio player test utility (latest version below):

https://www.ap.com/download/apx-portable-audio-player-headphone-test-utility-16/

Actually, I've just realised anyone can download this after filling out a quick registration form on the website (I won't upload it myself though as I'm not sure this is allowed). And I've also just seen AP owners might not even have to download it at all, as the documentation says:
APx500 series audio analyzers have the required program simulation noise signal built-in to the signal generator. In certain APx measurements, it’s available by setting the generator Waveform to Noise and the Noise Shape to BS EN 50332-1.

I've now redone the DA/AD loop Df test for my soundcard using the Program Simulation Noise, as well as switching to the rear audio connections on my PC as I noticed they're a lot less noisy than the front ones:

diff_loopback_PC.png



And below as an example measurement are the Df results for my Samsung Galaxy S10e (Qualcomm Snapdragon variant, with WCD9341 audio chip, used in all the S8, S9, S10, Note8 and Note9 series phones), again playing the Program Simulation Noise, and measured using the above PC soundcard:

diff_S10e_EN50332.png


This is better than the Df value of the Program Simulation Noise measured for the LG V30/V40 here (-32.1 dB), suggesting the relatively low measured SINAD of the S8+ of 89dB (compared to the LG which is likely ~109dB as it uses the same audio chip as the G7 measured on here) is not indicative of its actual degradation of music (assuming the S8+'s Df value would be comparable to my S10e, seeing as they uses the same audio chip). If correct, this could mean the sound quality of many other devices may also be misrepresented by the SINAD metric, either having less degradation than it suggests, or more in other cases. Of course, the LG results in the link above were made with a different ADC (the RME Babyface Pro) than mine, so the results are not precisely comparable, but it should be noted that my soundcard has a loopback Df ~5dB worse than the Babyface Pro, yet my S10e's Df value measured by the former is still better than the LG's measured by a better ADC, so measuring my S10e with the same Babyface Pro ADC would likely decrease (improve) its Df value even further ahead of the LG.

As can be seen here, just a couple of Df measurements that literally took 5 minutes have revealed a lot of usefeul (and surprising) information. I think it's definitely a metric that deserves more investigation. Obviously precise Df measurements and quantification of the degree of any (non-)correlation it has with SINAD will require precise ADCs with very low signal degradation such as AP analyzers to elucidate fully.
 
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bobbooo

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I think the way you used the word "compression" for SINAD refers to diminishing returns past some semi-arbitrary value which refers to "good" performance. But what I meant was that the Df metric compresses measured values into a smaller scale. It's still a static test of signal fidelity in the end.

Say it was implemented as part of the regular test suite. It would still have to be supplemented with all of the various electrical measurements, like level, power or gain. That implies that it would even translation into a graph: level vs. Df, or power vs. Df. At which point the metric starts to collapse since it's not referenced to SPL or psychoacoustic considerations.

I'm probably not being completely fair. My thinking here is that it seems like there is no reason to apply the Df to electrical signals given the kind of performance possible today. I would see it being, however, very useful for analyzing production plug-ins for DAWs, especially ones that are supposed to be transparent. That's one area of measurement that is still completely underdeveloped and which, I think, would cause a lot of people to pay attention.
I think pretty much all those points could equally be levelled at SINAD though. I don't see how the Df metric would 'collapse' if it were measured at different levels, just as SINAD doesn't. And I'd see Df as a metric to use along side all the other measurements, not a single score to replace everything else.

How do you know what kind of performance is possible today, when none of the standard metrics measure total sound degradation when playing music (or a close analogue thereof in Program Simulation Noise)? For example, as can be seen from these measurements, the FiiO M11 has a slightly better (lower) Df value for a 1kHz sine wave (implying a higher SINAD) than the Questyle QP1R, yet the former has a significantly worse Df value when playing real music or the Program Simulation Noise. Sine tone tests evidently miss a significant part of the sound degradation of a device, which can result in SINAD being a misleading metric. Df however is guaranteed to take all such degradation into account.

As for the point about 'compression' of the Df scale, I don't really see this as much of a problem. It could easily be rescaled for more intuitive reading if necessary, as @MZKM has done for some graphs of the speaker scores. The Df calculation could even be run between the difference signals of two devices using DeltaWave, which would give a 'relative Df value' in order to more clearly judge the difference in sound degradation between devices.
 
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bobbooo

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FYI:
https://www.audiosciencereview.com/...-adi-2-pro-fs-black-edition.10834/post-303239
https://www.audiosciencereview.com/...-of-amp-and-dac-measurements.5734/post-309900

I am not going to comment about DF Metric but you can download a lot of loopback recordings from gearslutz and analyze them using whatever method you like. Of course, if you use deltawave, better ask pkane when there are questions.
Yes I linked to that Gearslutz page and SoundExpert's calculations of those devices' Df values in previous replies. Thanks for the second link though, that's useful information that constructively adds to the discussion :)
 

bobbooo

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Found the original post.
No. It won't work. The benefit of FFT is being able to see deep down into the noise floor.
For time domain measurements, the resolution is equivalent of -120db in FFT. But you can't increase FFT resolution or use average.
There will be nothing but noise left when doing the nulling.
That would be the point of doing the loopback null test, to see the minimum level of noise the Df metric could measure using state of the art equipment such as the AP Analyzer. If that level is below pretty much every consumer device, then that Analyzer could be used to measure the Df values of those devices with enough accuracy to rank them in terms of sound degradation. It's the relative Df values between devices rather than absolute figures that matter really.
 
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One stupid question and I apologise for my ignorance, but for example since the best power amplifier measured in ASR: Benchmark AHB2 has a SINAD of 113db and it seems that the bottleneck in a system is the power amplifier as far as electronics concern, does it really matter if the dac has SINAD over this value? I mean what is the point in a system of having a dac of 120 SINAD if you have a power amplifier of 105 (Hypex NC400 for instance)? Do you actually gain anything or it is just a cool number and you have pride of ownership?
 

gvl

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Imperfections add up, if the amp was 90db SINAD then it would be the bottleneck, here they are more or less close so their individual contributions to the overall lowered numbers are similar, but yes the overall will be worse by the "worst" performing link in the chain.
 
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I don't have a spare $11,000 laying around just to boast of R2R . . . the repair bills on my Jaguar are killing me . . .
Isn't the Mola Mola technically a discrete non R2R DAC implementation to combat disadvantages of both delta sigma and R2R?

Am very impressed at this engineering feat achieved by Okto Research! Happy to support a company (my dac8 pro shipping hopefully this week!) willing to invest in such pursuits even if the actual performance may not be perceptible. And best of all the asking price is very reasonable for a product of this calibre.

I can see this easily priced at Mola Mola/Trinnov territory if they add QoL features such as native Dirac integration, a quality ADC + calibrated mic and Roon support.
 

AudioStudies

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Isn't the Mola Mola technically a discrete non R2R DAC implementation to combat disadvantages of both delta sigma and R2R?
I could be wrong, but I was under the impression that Mola Mola was R2R. But however it is designed, I can't afford $11,000 for its sound quality or the fancy Hawaiian name . . . the repair bills on my Jaguar are killing me . . . I might try to save up for the Okto though . . .
 

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