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Review and Measurements of Okto DAC8 8Ch DAC & Amp

Order #156 here for a streaming silver Dac8 Stereo. Hope Pavel will make a commercial success in this turmoil.
I got the same configuration (plus the remote). I’m expecting it to amaze me!
 
@EchoChamber
i see you are using topping d90 MQA.
I would like to hear your impressions of the Dac8 Stereo compared to the d90.
Absolutely, I'm very curious myself of the possible sonic differences both units might have. The D90 is excellent though, it will be hard to beat - the best DAC I've had so far.
 
By the way, I am just aware of and wondering that we have one AES/EBU digital "OUT" in DAC8PRO which always gives CH-1 + CH-2 digital signal; if we would connect this AES/EBU OUT into AES/EBU IN of the second DAC8PRO, then the two DAC8PROs would be automatically in sync, or not?
I will also PM to Pavel of OKTO for this inquiry....

I confirm this is going to work for syncing two units set to receive audio data over USB. The unit set to "Pure USB" mode will become a "master" unit, providing its clock to the other one, set to "USB/AES" mode, which will accommodate its frequency of data requests to the USB host in a way to be fully in sync with the signal received over its AES/EBU input. We have yet to test how a USB host running Windows will cope with two units and whether Thesycon, ASIO4ALL or both drivers will need to be used.

Funny, mine hasn't even shipped yet, and I ordered the Stereo on launch day (April 8th).
Be prepared for a seriously long wait..

The first batch of the dac8 Stereos has been shipped 2 weeks ago, more are shipping this week and the production rate should stabilize and only increase from now on. There was something we needed to take care of in regards the Raspberry integration. Thank you for your patience.

The only annoyance so far is the pop I get whenever I hit stop on a playing track when bitstreaming DSD music (DoP). This doesn't occur with PCM music. I also did not have this problem with the RME ADI-2 DAC. @Okto Research Any thoughts as to what might be going on?

We know about the issue and we are working on a fix. It is a software one, so we should be able to address it with a firmware update package that our software developers are working on.

Hi. Thank you for my dream DAC!
So what you are saying is that the dac8 does not need that info? XMOS & DAC chips processes 24/16 bit the same? Nothing special for 24? Since the DAC does not detect the info it must process the same.

All the data is processed as 32-bit internally and neither XMOS nor DAC chip is aware of part of the sample bits being padded with zeros.

"Far from reliable", is probably stretching it. Can you/anyone name ANY device that passes wrong info? And with AES? And MCH? Many devices, including my entire system relies on that info. The Vanity reclocks native signal. It detects that info in order to know how to reclock. Many DAC's do have bitrate. I guess it's a design decision for an off chance it might be wrong. Anyway, thanks for clearing that up.

During our testing, we came across multiple consumer, SPDIF devices that either did not provide the information about bit depth at all or it didn't reflect the actual data. We are going to have a look at this in the future in order to make the dac8 able to display the AES/EBU / SPDIF bit depth information when it is available and when the DAC is able to verify that it is correct.

Speaking of design, why no Clock input? All Pro DAC's have 'em. I imagine pro people would be way, way more interested in this product then us mere mortals. Now they wont/can't buy. Effects everyone because now DAW's (The source of our sources) will use substandard devices. So the universe would gain if Pro's/DAW's use this device.
BTW: This forum only tested clock with single device, but what about DAW's with 20+ devices with analog stages. Also, my Pro Trinnov (assuming many others) allows for a secondary audio, the unprocessed audio, Trinnov calls it wet vs dry. Anyway, all that's gotta be synced.

Congratulations! Well done. Give yourself a raise. (Of coarse clock input would give you around 900% raise...)

As answered in one of the subsequent posts, the AES/EBU or SPDIF signal already contains the clock. More than that, the AES/EBU or SPDIF frequency is equal to 2x the bit rate (or 128x sample rate), which (even though it has the biphase-mark coded audio data on it) makes it much easier for the receiver (and less prone to errors - jitter) to recover the bit clock from than from a slow word clock supplied through a separate connector. The dac8 PRO uses a combination of a very good receiver chip and Sabre's jitter eliminator in order to achieve the specified performance, even when using its AES/EBU inputs (regardless of whether AES/EBU or SPDIF signal is being fed to them). SPDIF and AES/EBU are, unlike UAC2 USB, synchronous protocols, so a significant timing error would lead to immediate loss of sync or audible sample drops.

I am afraid that there is a strong similarity between the idea of clocking in the pro audio and luxurious cables in the consumer audio. Trying to keep DACs fed with AES/EBU signal in sync using an external word clock kind of reminds trying to improve sound quality with directional cables placed on elevators.

Pavel, Okto Research
 
I confirm this is going to work for syncing two units set to receive audio data over USB. The unit set to "Pure USB" mode will become a "master" unit, providing its clock to the other one, set to "USB/AES" mode, which will accommodate its frequency of data requests to the USB host in a way to be fully in sync with the signal received over its AES/EBU input. We have yet to test how a USB host running Windows will cope with two units and whether Thesycon, ASIO4ALL or both drivers will need to be used.
Pavel, Okto Research

Hello Pavel,

Very nice to hear from you.

I also confirmed the AES/EBU sync connection from DAC8PRO to second DAC, in my case ONKYO DAC-1000(S) which has AES/EBU digital IN. I am using this AES/EBU (CH1+CH2) sync input to DAC-1000(S) and the RCA unbalanced output of DAC-1000(S) into L & R active sub-woofers. This is working perfectly fine in sync. Please refer to my post #1,619 in this thread and my specific post #190 in my multichannel project for the details.

I hope you would test and make it sure (or possible) that your specific DIYNHK ASIO driver would recognize 16 channels properly when we connect our PC to two DAC8PROs using two USB 2.0 cables while the first DAC8PRO's AES/EBU digital OUT (CH1+CH2) is connected to the second DAC8PRO's AES/EBU digital IN just for sync purpose. If the current DIYNHK ASIO driver for DAC8PRO cannot recognize 16 channels, then I (we) do hope you would update/upgrade the DIYHNK ASIO driver to enable this feature of 16 channel recognition.
 
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Is there meanwhile experience with alternative remote controls that work together with the Okto dac volume control?

It would be fine to get recommendations with information about manufacturer and model.
 
Hi all,

Finally the DAC8 Pro arrived today (#116)! It took almost a week from Prague to the Netherlands but that's bearable because I was waiting already so long ;).

Pavel did send me a download link for the DIYINHK USB audio driver for Windows computers also. Everything is running fine now (Intel NUC, Roon, DAC8Pro). In Pure USB mode (stereo) for the time being. Too soon to say something definitive about the sound quality but first impressions, after a few and sufficient minutes of burning in, are certainly not bad. It comes close to, or even surpasses, my more than 20 year old Assemblage DAC 2.6 signature DAC (multibit BB PCM1704 DAC chips). Some other (Delta-Sigma) DAC's I tried didn't quite manage this. I always thought I had to get used to it but not so with the DAC8Pro! Too bad the DAC 2.6 is showing it's age now and became rather noisy. Possible some of the elco's are finished I guess. I am glad I learned that in the DAC8 Pro there are no elco's in the main circuit, no relays etc.

In the coming weeks I will finish my new speakers (3 way active system powered by Hypex amps). That's the main reason I purchased the DAC8Pro!

John
 
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Hi all,

Finally the DAC8 Pro arrived today (#116)! It took almost a week from Prague to the Netherlands but that's bearable because I was waiting already so long ;).

Pavel did send me a download link for the DIYINHK USB audio driver for Windows computers also. Everything is running fine now (Intel NUC, Roon, DAC8Pro). In Pure USB mode (stereo) for the time being. Too soon to say something definitive about the sound quality but first impressions, after a few and sufficient minutes of burning in, are certainly not bad. It comes close to, or even surpasses, my more than 20 year old Assemblage DAC 2.6 signature DAC (multibit BB PCM1704 DAC chips). Some other (Delta-Sigma) DAC's I tried didn't quite manage this. I always thought I had to get used to it but not so with the DAC8Pro! Too bad the DAC 2.6 is showing it's age now and became rather noisy. Possible some of the elco's are finished I guess. I am glad I learned that in the DAC8 Pro there are no elco's, relays etc.

In the coming weeks I will finish my new speakers (3 way active system powered by Hypex amps). That's the main reason I purchased the DAC8Pro!

John
Wow, I also had an Assemblage DAC... I wish I could be as mature as you and keep it for 20 years.

Enjoy your dac8!! If I get mine in SeptemberI’ll be happy. :)
 
Hi John,
What kind of software will you use for the crossover and dsp?

Well, none, at least not at the moment. I have a MiniDSP nanoDIGI 2x8 DSP (2 S/PDIF inputs and 8 S/PDIF outputs) which is programmable of course. I am building one of Sigfried Linkwitz designs (LXmini studio) and this solution has the advantage that I know the exact parameters for the crossover as part of the design. I don't know if a pure software solution is 100% equivalent.

Also, it was not until I visited this forum and this thread more regular that I realized that it can all be done in software on the Roon core (a Intel i5 NUC) through USB in real time. But I will look into that later.

John
 
Well, none, at least not at the moment. I have a MiniDSP nanoDIGI 2x8 DSP (2 S/PDIF inputs and 8 S/PDIF outputs) which is programmable of course. I am building one of Sigfried Linkwitz designs (LXmini studio) and this solution has the advantage that I know the exact parameters for the crossover as part of the design. I don't know if a pure software solution is 100% equivalent.

Also, it was not until I visited this forum and this thread more regular that I realized that it can all be done in software on the Roon core (a Intel i5 NUC) through USB in real time. But I will look into that later.

John
You might want to read what Dave Dre says. He says different components set to identical crossover and eq parameters yield different results which require tweaking and tuning. He finds that true of differnet miniDSP models and goes into it in some length on the Linkwitz users group.
 
You might want to read what Dave Dre says. He says different components set to identical crossover and eq parameters yield different results which require tweaking and tuning. He finds that true of differnet miniDSP models and goes into it in some length on the Linkwitz users group.
Yes, I have read something about that lately. But Dave (who also frequents this forum I believe) also suggested some rather heavy tweaks from the original design of the LXmini (which are mostly received quite well by users BTW). So I don't know what to think about it. I first try to follow the original design as accurate as possible except of using the miniDSP units with their integrated DAC's. I think the DAC8 Pro instead will be superior sounding. After everything is completed I eventually may do some tweaking and playing with the settings myself. After all it's a hobby!

John
 
Amirm recently posted a review of the new DAC8 Stereo which, BTW, took the lead in SINAD performance with more than 122 dB (see https://www.audiosciencereview.com/forum/index.php?threads/okto-dac8-stereo-dac-review.14705/ ). Now the detection limits of the APx555 Audio Analyser are reached by a hair I don't expect this record will be broken anytime soon :).

In that thread I also posted a picture of the internals of a recent production unit (July 2020) of the DAC8 Pro. If you missed that thread see the picture below (BTW, forum member Dualazmak posted this before but he deleted his picture later).
There are several major changes compared to the early prototype as tested by ASR in March 2019. If you ask me it's a very neat lay out (much less cabling than the prototype) which may be contribute to the improved spec's too, but I am not sure about that of course. But in general a lot of small details become important to get the very best performance from a DAC chip. Also, the case got some improvements like thicker sheet metal, less deep and no ventilation holes (heat is controlled by conduction instead with a aluminium CNC machined plate under the DAC print (on the right). This is not visible from the picture.


DAC8PRO internals.jpg
 
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(BTW, forum member Dualazmak posted this before but he deleted his picture later).
Yes, I once showed several high resolution close-up pictures of the inside of DAC8PRO in this thread and in my thread, but later I deleted them since there were some discussions on IPR, copyright aspects of the internal design. Please PM me for further info on this issue.

I fully agree with John1959 for the considerable improvements of simple and beautiful internal design, new parts and cabling of DAC8PRO, and I know these improved features are also fully implemented in their DAC8 Stereo.

I assume all of you are well aware of recent amazing review by amirm on DAC8 Stero dated July 15; all the people interested in OKTO's wonderful products and activity should read that review on DAC8 Stereo.
 
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Placed order #186 today for the DAC8 pro
 
Am I right in thinking that the USB interface on the DAC8 Pro also supports eight channels? That's what I understand from the website. Though I may have got confused from the manual talking about the AES/EBU input outputting two channels from the USB input.
 
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Correct. Either via USB or 4 x AES(2x). The AES outputs (@ 0db) are darn handy, though:)
I remain gobsmacked by my Okto8 every time I use it.
o_O
 
DAC8PRO's AES/EBU digital out is the "through" digital signals of channel-1 and channel-2 which means the AES/EBU out is not under the DAC8PRO's pre-amplifier functionality including the volume and gain control. AES/EBU signal contains sync clock information, so you can sync the second DAC (with AES/EBU digital Input function) with DAC8PRO.

I hope my post here will give you some perspectives for your understandings.
 
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