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Okto dac8 stereo DAC Review

John1959

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@Kal Rubinson, would Stereophile review the Okto dac8 Stereo? I bet many would be interested in both John's take on the measurements and the subjective reviewer's impressions vis-à-vis car/house priced competition!
I am not sure JA's Audio Precision SYS2227 analyzer is fully up to the task ... But yes, I would like to see a review anyway.
 
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MRC01

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DACs are getting very good. But it took a long time to get there. Bad digital distortion is much more offensive than bad analog. So going to the extreme is a good thing to ensure audible distortion is never possible with normal use.
I agree DACs have improved over the years. But digital distortion doesn't seem worse than analog to me. For just one example, I used to dread the LP nearing the inner groove, as I could hear the distortion increasing (yes I had the tonearm aligned right).
 

Matias

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I am not sure JA Audio Precision analyzer is up to the task fully ... But yes, I would like to see a review anyway.
John Atkinson has been using an APx555 now too, but on loan as usual hehe.
 

Kal Rubinson

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@Kal Rubinson, would Stereophile review the Okto dac8 Stereo? I bet many would be interested in both John's take on the measurements and the subjective reviewer's impressions vis-à-vis car/house priced competition!
It is not my call but I will be commenting on the DAC8 Pro as part of the review of a streamer.
 

infinitesymphony

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Definitely interested in hearing a bit more discussion about intersample overs. Benchmark, RME, and other studio/broadcast oriented brands leave headroom for them, this DAC may not. What's the consensus -- big deal, or no big deal?
 

AudioStudies

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According to Alexa the forum value has increased by over $130000 since Amir bought the analyzer. That’s without including a cent of donations. So good investment on his part. But I’m sharing my info on analyzers for everyone else. Folks who would rather save $25k for better results.
Then why haven't you put it in a separate thread, as you have been asked many times? Rather you say you will do it later, and keep commandeering this thread.
 

EchoChamber

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Then why haven't you put it in a separate thread, as you have been asked many times? Rather you say you will do it later, and keep commandeering this thread.
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.
 

AudioStudies

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Do you always refer to yourself in a plural form? That's a sign of a mental condition, you should seek a professional consultation.
Talk that way to a Police Officer and you can get multiple tickets . . .
 
OP
amirm

amirm

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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:
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.
 

JohnYang1997

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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.
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.
 

ReaderZ

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Wow. The cleanest multitone I've ever seen (apart from your AP). You really get what you pay for.

The 8 channel one reviewed before has much cleaner one than this. This is great, that is just insane.
 

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.
 
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