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Review and Measurements of Okto DAC8 8Ch DAC & Amp

jjk

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I think it is possible the problem I was having with my DAC8 was its proximity to my 65 inch Panasonic Plasma.
For ease of access I had the DAC8 positioned under the edge of the plasma, on top of the cabinetry for ease of initial testing.
When I moved the DAC8 to my kitchen and replugged, the pushbutton was fine and was able to program the remote correctly. Have been re-testing all day and still good. Was the EMI from the plasma the problem?
The DAC8 will go inside the cabinet so I am hoping that the increased distance and the mahogany will be enough to shield the Okto.
Will update. Stay safe.
 

Vincentponcet

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View attachment 64543
Room temperature today here is 20 degree C. My DAC8PRO, sitting on top of my audio cabinet, is working perfectly in Pure USB mode, 192 kHz 24 bit operation in all of the 8 channels. The top cover temperature is well below my "healthy" body temperature, so the 26 degree C indication is just OK, I believe. Fortunately, I have no problem at all including the remote.
I see yours has firmware 1.32. Mine has firmware 1
Where do you get firmware update ?
 

dualazmak

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I see yours has firmware 1.32. Mine has firmware 1
Where do you get firmware update ?

My DAC8PRO order #106 arrived on May 9 with firmware 1.32 in it! You would please contact Pavel for possible firmware update, I believe you can do it through USB connection. I found somewhere (do not remember where it is) Pavel informed that future firmware update would be possible through USB connection.
 
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dualazmak

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I think it is possible the problem I was having with my DAC8 was its proximity to my 65 inch Panasonic Plasma.
For ease of access I had the DAC8 positioned under the edge of the plasma, on top of the cabinetry for ease of initial testing.
When I moved the DAC8 to my kitchen and replugged, the pushbutton was fine and was able to program the remote correctly. Have been re-testing all day and still good. Was the EMI from the plasma the problem?
The DAC8 will go inside the cabinet so I am hoping that the increased distance and the mahogany will be enough to shield the Okto.
Will update. Stay safe.

This is very important info for me too, since I also have Panasonic Plasma TV. Fortunately the Plasma TV is in our dining room, far away from my DAC8PRO in living/listening room.
 
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Burning Sounds

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I think it is possible the problem I was having with my DAC8 was its proximity to my 65 inch Panasonic Plasma.
For ease of access I had the DAC8 positioned under the edge of the plasma, on top of the cabinetry for ease of initial testing.
When I moved the DAC8 to my kitchen and replugged, the pushbutton was fine and was able to program the remote correctly. Have been re-testing all day and still good. Was the EMI from the plasma the problem?
The DAC8 will go inside the cabinet so I am hoping that the increased distance and the mahogany will be enough to shield the Okto.
Will update. Stay safe.

Thanks for taking the time to do this @jjk - it adds further evidence to my findings (post #1,509) that it is RFI/EMI causing the problem with the remote sensor. I don't have a plasma TV, but I do have a large class D amp with four vertically oriented NC502MP modules which I am sure is the culprit in my case. Placing the Dac8 about a foot above the amp (with my Mytek 8 channel Dac on the shelf between them) solved the problem for me. About a foot to the side of the amp also worked fine, too, but was less aesthetically pleasing. Hopefully you will be able to find a location in your cabinet that will work for you. I don't think there is any need to be concerned about the Dac 8 overheating inside a cabinet as the interior cooling has been very well implemented.
 

Burning Sounds

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I suggest getting one with Ammeter. Great tool for: To be more intimate with your sources, debugging & early alarm.
Not to mention the pleasure I (everyone?) get when I see it it go up. I love when my sources eat power!

Getting more intimate with my sources....pleasure when I see it go up....careful now! :p

 

Okto Research

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Hi everyone!
There are some tests about the stereo dac ?

I hope order will be available soon :)

Is there anyone here with a stereo model? I am interested in it but nowhere can I find the impressions of the people who own it or some more detailed SQ review?

The dac8 Stereo is ready to be sent to ASR and the first orders are shipping next week. Right after that the product will become available again on our website.

Hey. This is big problem: The display does not display bitrate.

The display is not like page 1 nor the manual so that should be corrected. Bummer, I was looking forward to the bitrate. Trinnov doesn't either display bitrate.

My biggset gripe is that it does not display bitrate like manual. I really, really wanted that.

Just noticed the Manual shows USB with the bitrate. So maybe only USB shows bitrate? I'm AES.

Can anyone confirm if bitrate is displayed with USB?

Bits per sample information is only displayed in either USB or USB/AES mode (for USB data). The reason is that while a USB host explicitly provides this information, the device receiving SPDIF or AES/EBU signal needs to rely on status data provided by a transmitter device. Unfortunately, these are far from reliable since a lot of devices just don't bother with sending the status data correctly based on the actual audio data and either fill them with zeros or send incorrect, fixed values. To avoid confusing users with misleading bit depth values, we just omitted that completely in Pure AES mode. The displayed sample rate is a different topic, that reading is obtained in other way and is reliable.

Question: If I understand the measurements, no DAC today gives full 24 bit? The best known DAC only gives 21 bits? And the Dac8 only 20 bits?

If so, wonder why did the host not mention this? This is very important to know. Maybe I am not understanding the measurements?

Yep, analog is hard. 24-bit or 144.5dB dynamic range would require a device with a full-scale voltage of 4V to have just 0.25uV of noise. That is not unattainable, but it would very difficult, costly and space-consuming to do, especially for 8 channels. Not even the APx555 generator, let alone DAC, approaches such a low noise level and that is almost a $30,000 device.

High dynamic range (or low noise) in DAC is definitely good when you do some DSP and need to attenuate part of the band in order to boost other region. Also, it makes digital volume basically a superior solution, since its only downside - leaving noise level unchanged - is not an issue if the noise is far below audible treshold. What is left is fluency and lack of relay clicking.

Does the current production version measure better than early versioni measured by amirm? Why is conduction better than convection for this case? Thanks in advance.

It does. Production dac8 PRO got a new generation DAC board, which measures roughly 2dB SINAD better and has increased dynamic range.

Conduction cooling doesn't rely on airflow that much and allows for a dust-proof case free of venting holes. Lower temperature also slightly contributes to lower noise.

3D Issues with DAC:

The dac8 screen, even at lowest setting, flickers very, very distractedly with 3d glasses. I was forced to cover display during 3d viewing.

Good catch! But you don't need to cover the displays, just make them automatically turn off by setting Menu > Displays > Timer to "10s" and Menu > Displays > After timer to "off". Then they will only light up briefly after making a change.

Small issues.

Twice the DAC was unresponsive to the remote only (dial was responsive) and did not auto shut off after the 10 min settings. Unplugging fixed. PITA because 5 minute process for me to get behind rack. Oddly it only loses the auto shut off settings after reboot & reverts back to 2 hours.

I don't care about remote so much as I don't plan on using it. Just wanted a DAC. Auto shut off is important. I guess the BOM - learned that word here :) - for a switch was too great. In this day & age, when rebooting solves most problems it seems like a missed opportunity & we should have increased price. Perhaps switches mess with SINBAD's? But better measured DAC's have switches...
Given that the Dac has a case without vents I'm presuming that RF/EMI is affecting the remote sensor via the front panel. Early plasma TVs cranked out a far amount of RF and were known to interfere with Apple TV remotes. It's just a guess and perhaps others (or Pavel) with more technical knowledge can respond to my findings.
Arrg! My DAC didn't/won't shut off again & is coupled with not responding to remote. I only used it for a few seconds to take a pic this morning. So happened every day in my 3 days. I'm just going to leave on forever & problem solved for my usage. Since Trinnov must do volumey stuff in crossover & EQ, I'd rather not mix volume tech anyway.

Okto boasts 10+ years.

Does that mean on continuously? Well what choice I got? If it breaks, I'll just get a new one. No way I'm opening my rack after every usage.

Chalking it up as a win and minor issue.

Should I email Okto let them know that my DAC doesn't shut off as an FYI? I feel bad to bug them after their amazing contribution in A/V history. The first (known) rug that completes the room in A/V.

Hm. Thanks, I missed that. Wonder what's been added/changed in 1.32.
@Okto Research ??

Since 1.31 firmware version, we sped up the user interface by increasing display update speed 20x, which results in almost instantaneous response to user commands. Unfortunately, this also had an adverse effect on a remote reception and caused susceptibility to electromagnetic interference, which may break responsivity to IR commands and all the functions concerning timing.

We already fixed that in 1.34 so the new devices don't suffer from that, and we are preparing a firmware update package for the existing devices. If you are experiencing issues, the dac8 PRO needs to be moved away from the source of EMI, which might be a D-class amplifier like in case of @Burning Sounds, a plasma TV like in case of @jjk (probably) or generally a device with switch-mode power supply.

In all FW versions, the menu settings are only stored when a soft power off is performed (no matter if using knob or remote) in order to save flash memory write cycles. The settings from the last session are lost if power cord is pulled, so this behavior is normal.

Hmm, might be enough though. The Okto Dac doesn't have any RFI/EMI mains input filtering - complete speculation on my part though as to whether this is the cause of this remote issue.
Susceptability to mains EMI would show up in a measurements. The issue here only concerns IR receiver, not internal circuitry.

Please feel free to start charging double. The bargain price is inviting suspicion on the performance.
Ok then, waiting for the second half of your payment! But really, once our products are in stock, there will be some price increase.

I'm version 1.32

I'm not troubled. What is the harm leaving it on? Longevity, perhaps? Ideally an even better device comes along between now & 5-7 years, preferably in small form factor :)

There is close to zero harm in leaving your dac8 PRO on. The power consumption is around 7W so it is not going to break the bank either.

Pavel, Okto Research
 

dualazmak

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Hi everyone!
...
...
Since 1.31 firmware version, we sped up the user interface by increasing display update speed 20x, which results in almost instantaneous response to user commands. Unfortunately, this also had an adverse effect on a remote reception and caused susceptibility to electromagnetic interference, which may break responsivity to IR commands and all the functions concerning timing.

We already fixed that in 1.34 so the new devices don't suffer from that, and we are preparing a firmware update package for the existing devices. If you are experiencing issues, the dac8 PRO needs to be moved away from the source of EMI, which might be a D-class amplifier like in case of @Burning Sounds, a plasma TV like in case of @jjk (probably) or generally a device with switch-mode power supply.

In all FW versions, the menu settings are only stored when a soft power off is performed (no matter if using knob or remote) in order to save flash memory write cycles. The settings from the last session are lost if power cord is pulled, so this behavior is normal.

Susceptability to mains EMI would show up in a measurements. The issue here only concerns IR receiver, not internal circuitry.
...
...
Pavel, Okto Research

Hello Pavel,

Thank you for your nice updates.

The info on interference from Plasma TV and D-class amplifier is very important for me since I have Panasonic Plasma TV (fortunately sitting far away) and I am planning to purchase a D-class multi-channel amplifier just like the one @Burning Sounds has.

As for your info;
>the settings from the last session are lost if power cord is pulled, so this behavior is normal.
I am connecting the power cord to my multi-power distributor, and this means DAC8PRO is pulled-off everyday when I shutdown my entire audio system. I found, however, at least the master volume value (e.g. -7 dB) is memorized even pulled-off, and will appear in the same value (-7 dB) when powered-on next morning. Is the flash memory volatile or non-volatile?

In any way, I am afraid that it would be volatile, and this is the main reason I would like not to set/memorize the relative gains for each of the 8 channels, and would like to save/control the relative gains by the software crossover in my project, as I wrote here.

As you know, my firmware is 1.32 now, and I am looking forward to hearing from you soon regarding the firmware update package to 1.34 or higher.
 
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Burning Sounds

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Hello Pavel,

Thank you for your nice updates.

The info on interference from Plasma TV and D-class amplifier is very important for me since I have Panasonic Plasma TV (fortunately sitting far away) and I am planning to purchase a D-class multi-channel amplifier just like the one @Burning Sounds has.

As for your info;
>the settings from the last session are lost if power cord is pulled, so this behavior is normal.
I am connecting the power cord to my multi-power distributor, and this means DAC8PRO is pulled-off everyday when I shutdown my entire audio system. I found, however, at least the master volume value (e.g. -7 dB) is memorized even pulled-off, and will appear in the same value (-7 dB) when powered-on next morning. Is the flash memory volatile or non-volatile?

In any way, I am afraid that it would be volatile, and this is the main reason I would like not to set/memorize the relative gains for each of the 8 channels, and would like to save/control the relative gains by the software crossover in my project, as I wrote here.

As you know, my firmware is 1.32 now, and I am looking forward to hearing from you soon regarding the firmware update package to 1.34 or higher.

Yes, when I was experiencing the remote sensor problem I would reset the Dac so it would again become usable with the remote by unplugging from the mains - both the volume setting and the channel routing settings were retained.
 

jjk

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My DAC8 still does not respond properly to the remote (actually it does not respond at all). I tried for 3 1/2-4 hours yesterday positioning the Okto in several locations in my AV cabinetry but either by time (less than 5 minutes) or by using my Harmony remote to switch between Directv and Computer Audio, the control of the machine was lost. I could reset temporarily by unplugging but the above would rapidly repeat. After several cycles of this behavior, the pushbutton also lost function.
What may be possible, depending on agreement with Pavel is to employ the machine in "DAC only" mode (0 dB), power on 24/7, and control volume and switching through an alternative MCH balanced preamp.
I welcome any comments or suggestions. Stay safe.
 

Okto Research

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My DAC8 still does not respond properly to the remote (actually it does not respond at all). I tried for 3 1/2-4 hours yesterday positioning the Okto in several locations in my AV cabinetry but either by time (less than 5 minutes) or by using my Harmony remote to switch between Directv and Computer Audio, the control of the machine was lost. I could reset temporarily by unplugging but the above would rapidly repeat. After several cycles of this behavior, the pushbutton also lost function.
What may be possible, depending on agreement with Pavel is to employ the machine in "DAC only" mode (0 dB), power on 24/7, and control volume and switching through an alternative MCH balanced preamp.
I welcome any comments or suggestions. Stay safe.

Steve, I suggest you to opt for a refund or replacement as suggested by me in e-mail previously. Remote on your dac8 PRO operated properly while the unit was away from your plasma TV, but the issue came back after you returned it to the original location. I tried to describe the reason as well as I could in e-mails and also here on ASR.

Just for the clarification to others - the problem with pushbutton does not concern other units. In this unit, it is caused by a too tight fit between a Teflon stiffener ring and a knob.

Pavel, Okto Research
 

Kees Huizinga

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Now that I own the dacpro8, an amplifier with hypex modules, a recent computer and some fantastic speakers, I have practically finished this hobby for a long time.
Now I was wondering if there is still something to improve? My thoughts go out to the USB output. What are the experiences here on the forum with devices such as the Audiomatrix element H, or JCat?
 

Feyire

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Now that I own the dacpro8, an amplifier with hypex modules, a recent computer and some fantastic speakers, I have practically finished this hobby for a long time.
Now I was wondering if there is still something to improve? My thoughts go out to the USB output. What are the experiences here on the forum with devices such as the Audiomatrix element H, or JCat?
Room EQ?
 

dualazmak

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Now I was wondering if there is still something to improve?

To build a new house with "ideal and perfect" audio dedicated listening room. Do you already have one?
 

dualazmak

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dualazmak

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Hello Kees,

Just for your info... although not directly related to DAC8PRO,

As reported in my thread-post today, Guillaume of LUPISOFT kindly responded to me informing;
"EKIO uses IIR filters. The processing is done using a cascade of second order transposed direct form II biquad sections. Every calculation is done using 64 bit floating point numbers."

Please refer to here and here for further details.
 

Kees Huizinga

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With Dephonica it is possible to listen with IIR or FIR. To be honest, I find it difficult to determine the differences. I have not been able to detect the dreaded ringing at FIR with 4th order filters. You have a license for Dephonica, maybe you have a better hearing than me.
 
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