Review and Measurements of Okto DAC8 8Ch DAC & Amp

[Neddy]

Drool.
VanityHD/103 seems like THE perfect solution for a mixed audio/HT system (PC audio only USB + Bluray/streamer stick HT via AES)!
You wouldn't happen to have a spare Vanity card, would you?
Seriously, though, would you happen to have an email address for AudioPraise? Their website only lists a phone number....
My guess is that you'll be astounded by the OktoDAC when it arrives - best wishes!!

 

[rickyhgarcia]

Tried to buy the DAC8 Stereo last night, but no CC payment available yet. @Okto Research

Please help me with the options available:

1)The owner´s manual implies that the non-streaming version of the DAC will not include the Raspberry Pi board, correct? The specifications indicate that Ethernet or WiFi is available through the Raspberry Pi, correct? So the non-streaming version of the DAC has no Internet connection. In this case, and if there is a firmware upgrade by Okto, how is the firmware updated?

If I connect a PC (connected to the Internet) to the USB input of the DAC, why the streaming version is necessary? Is it better to stream directly to the DAC, or it is just the same to stream via PC to the USB input?

2)Do not fully understand the "Custom Output Voltage" option. I guess it makes sense to precisely match the DAC to the preamp/amplifier. But, what happens if the preamp/amplifier is changed during ownership? Is this a value that the user can change later on? There are no instructions for this in the owner´s manual? If this option is not purchased, how is the DAC set? Is it set to a generic value that works with most preamps/amplifiers?

 

[John1959]

ad 1.
I don't know about the firmware upgrades (through USB?) but the streaming option is a nice feature because it's in fact a small but powerful PC build into the DAC enclosure so you don't need an external streamer. So it's not necessary, the DAC8 pro doesn't have this option.

ad 2.
Don't worry about this if you don't know if you need it . I think it's meant for studio/professional usage where higher voltages are common than the standard approx. 4 V (balanced) output. There is no need to precisely match output voltage. 4 V should be oké in almost all cases. Note that the tested DAC8 Pro version had a lower voltage than 4 V on the analog outputs but this is no longer the case, as I have learned from the manual.

John.

 

[wineds]

ad 1.
I don't know about the firmware upgrades (through USB?) but the streaming option is a nice feature because it's in fact a small but powerful PC build into the DAC enclosure so you don't need an external streamer. So it's not necessary, the DAC8 pro doesn't have this option.

ad 2.
Don't worry about this if you don't know if you need it . I think it's meant for studio/professional usage where higher voltages are common than the standard approx. 4 V (balanced) output. There is no need to precisely match output voltage. 4 V should be oké in almost all cases. Note that the tested DAC8 Pro version had a lower voltage than 4 V on the analog outputs but this is no longer the case, I have learned from the manual.

John.

The custom output voltage is for amplifiers like the purufi 1et400 which requires about 11v when unbuffered to fully drive.

And firmware update will surely be via USB regardless of whether the rpi is present.

 

[John1959]

Well, I don't think Okto Research did offer the option of custom output voltage especially with the Purifi amps in mind, but for sure it's an interesting option to bypass the buffer amp (at the cost of less gain)! Nevertheless, also the Purifi amps will run perfectly on the 4V output if you don't disable the buffer amp on it. I am not sure the bypass of the buffer amp will gain any audible difference though.

John

 

[wineds]

Well, I don't think Okto Research did offer the option of custom output voltage especially with the Purifi amps in mind, but sure it's an interesting option! Nevertheless, also the Purifi amps will run perfectly on the 4V output if you don't disable the buffer amp on it.

John

Yes I was just citing that as a possible usage example.

 

[Neddy]

New topic: AES Output MUTE function - software change request.

Is anyone else using the OktoDACs stereo AES outputs?
Would you be interested in asking Pavel to add AES output MUTE to the (remotes) mute function?

I recently had an Asio driver issue, which, during troubleshooting, led to a situation where all my outputs went to full.
(Yes, Ouch...all cats vacated the room asap.)
In my setup, the Okto/Apple remote will mute the analog outputs, but not the main Ch1&2 AES output.

I did some brief research, and it appears that external AES mute switches are neither common nor cheap, but found several suggestions to request AES output mute function be added to the source gear software, hence this topic.

(I gather that volume control/mute functionality may not be part of the 'normal' AES spec, but haven't bothered to research it.)

@Okto Research : Is this possible for you to even do in software?

Thanks much!

 

[Max]

Wow! But... do I see some clipping in the wave graph or is just my other personality playing the devil's advocate?

Nope, impossible. Clipping (in time domain) would be seen directly through many and significative harmonic sidebands (in frequency domain). Here, the FFT is very clean, so no clipping at all.

 

[Russ_L]

Hi guys - I'm close to ordering the DAC8 Stereo with the streaming option. I currently use an SOtM sMS-200 for streaming (rOON endpoint). The 200's capability at the ethernet input is PCM 32/768 KHz (max) and DSD 64, 128, 256, 512. However nowhere can I find any info on what the Stereo DAC8 can accept with RoPieee loaded on the Pi4 card. Any help would be appreciated. Thanks.

Russ

 

[Nikolas]

Nope, impossible. Clipping (in time domain) would be seen directly through many and significative harmonic sidebands (in frequency domain). Here, the FFT is very clean, so no clipping at all.

Yep I sort of know that. It just seemed that the top of the sinusoid was cut - probably just a plot artifact!

Question: do you think the extra L+R in the Stereo could be useful (read: "usably" useful) for a subwoofer integration, or an external crossover and the Pro should be the way to go? What are the edge cases?

 

[Max]

Question: do you think the extra L+R in the Stereo could be useful (read: "usably" useful) for a subwoofer integration, or an external crossover and the Pro should be the way to go? What are the edge cases?

Good question !
As you say, with a DSP unit plus the Dac8Pro version, you can set up the crossovers independantly as needed (maybe a bit oversized with the multiple unused outputs). With the Dac8Stereo, you should be able to use some DigitalRoomCorrection (by Volumio, with FIR convolver plugin). It's not a crossover as defined (and it's maybe not the cleaner way to do it, in an ideal world) but it could do well the job. And in this case, the second output will be perfectly suitable (however, for this task, a simple passive splitter is equivalent).
But it's just my humble opinion : I've never used a sub until now and I just begin to wonder if I will ...

 

[Nikolas]

Good question !
As you say, with a DSP unit plus the Dac8Pro version, you can set up the crossovers independantly as needed (maybe a bit oversized with the multiple unused outputs). With the Dac8Stereo, you should be able to use some DigitalRoomCorrection (by Volumio, with FIR convolver plugin). It's not a crossover as defined (and it's maybe not the cleaner way to do it, in an ideal world) but it could do well the job. And in this case, the second output will be perfectly suitable (however, for this task, a simple passive splitter is equivalent).
But it's just my humble opinion : I've never used a sub until now and I just begin to wonder if I will ...

Ideally I'd put a MiniDSP SHD Studio in front of the DAC, and my biggest concern is time alignment of the subwoofer (volume matching is trivial and can be taken care of by Dirac), since I'm space constrained. I'll explain.

I plan to get a pair of ELAC ARB51 as mains and an Rythmik Audio E15 as subwoofer. Both are fully analogue internally, so there should be no lag/delay problems when used full range (but I'm not 100% sure until I measure with REW). Now, the ELACs are said to suffer a bit of port chuffing, so I'd use the high-pass filter embedded (yes, they have such filter on the rear) to 80 Hz. And I'd do the same (low-pass) on the subwoofer. Now we have a delay problem. The sub has a continous phase adjustment knob 0°-180°, but the high-pass on the mains should add more delay (in the 180°-360° range). This leaves me with listener-speaker distance as the only touchable variable, and at 80 Hz I don't have 334/80/2=2.10 m of space to experiment with.
All this, if I didn't make any mistake, if I feed mains and subwoofer with the same signal as provided by the Stereo.
If I enable the crossover in the SHD Studio instead, I can set independent delays per channel and therefore place sub and mains in the same plane in space. But I'd have to use the Pro - slightly worse measures but still best-of-the-world among multichannel DACs. And, should the MiniDSP fail for whatever reason, I wouldn't be able to use the sub with any 2.0 track (ie. basically 100% of my music library).

The big question here: is my analysis of what happens with the Stereo correct? Maybe Dirac can correct that phase jump?

 

[Okto Research]

Can the non-streaming version be later upgraded by simply adding the Raspberry Pi module? Or does it lack the integration hardware?

Yes, it can. The streaming version of the dac8 Stereo also includes an SD card, USB Wi-Fi adapter and a USB interconnect. In case you add the Raspberry Pi later on by yourself, you need to choose a Wi-Fi adapter carefully so it has an antenna that can be rotated into an upwards position (the Pi is mounted upside down). Our custom-made USB interconnect can be substituted with a cable.

1)The owner´s manual implies that the non-streaming version of the DAC will not include the Raspberry Pi board, correct? The specifications indicate that Ethernet or WiFi is available through the Raspberry Pi, correct? So the non-streaming version of the DAC has no Internet connection. In this case, and if there is a firmware upgrade by Okto, how is the firmware updated?

If I connect a PC (connected to the Internet) to the USB input of the DAC, why the streaming version is necessary? Is it better to stream directly to the DAC, or it is just the same to stream via PC to the USB input?

2)Do not fully understand the "Custom Output Voltage" option. I guess it makes sense to precisely match the DAC to the preamp/amplifier. But, what happens if the preamp/amplifier is changed during ownership? Is this a value that the user can change later on? There are no instructions for this in the owner´s manual? If this option is not purchased, how is the DAC set? Is it set to a generic value that works with most preamps/amplifiers?

1) The firmware update of the dac8 Stereo will be uploaded over USB. Some streaming software/network players that you will be able to install on the Raspberry Pi have their own "over the air" update functionality, which does not concern dac8 Stereo firmware.

2) The output voltage is set with tiny, high-precision resistors on the DAC board, so unfortunately, there is no simple way to change the output voltage later on. For this level of performance, the layout needs to be as tight as possible, so trimmers or switches are not an option.

New topic: AES Output MUTE function - software change request.

Is anyone else using the OktoDACs stereo AES outputs?
Would you be interested in asking Pavel to add AES output MUTE to the (remotes) mute function?

This is definitely doable in firmware and we should be able to include it into a firmware update package when we release it.

Hi guys - I'm close to ordering the DAC8 Stereo with the streaming option. I currently use an SOtM sMS-200 for streaming (rOON endpoint). The 200's capability at the ethernet input is PCM 32/768 KHz (max) and DSD 64, 128, 256, 512. However nowhere can I find any info on what the Stereo DAC8 can accept with RoPieee loaded on the Pi4 card. Any help would be appreciated. Thanks.

Russ

Formats accepted over Ethernet and Wi-Fi are only limited by the software installed on the Raspberry Pi and the bandwidth of the respective connection. However, the dac8 Stereo does only accept up to 384kHz PCM / DSD256 on its USB ports so unless you do resampling in the Raspberry Pi, that is the upper limit.

 

[Max]

The big question here: is my analysis of what happens with the Stereo correct? Maybe Dirac can correct that phase jump?

I'm not the most qualified to answer but I'm sure you will find help in the dedicated subsection of this forum

 

[Neddy]

Thank you, Pavel!
I'll drop you a note via email formally requesting the AES MUTE function - yay!!!

 

[rickyhgarcia]

Yes, it can. The streaming version of the dac8 Stereo also includes an SD card, USB Wi-Fi adapter and a USB interconnect. In case you add the Raspberry Pi later on by yourself, you need to choose a Wi-Fi adapter carefully so it has an antenna that can be rotated into an upwards position (the Pi is mounted upside down). Our custom-made USB interconnect can be substituted with a cable.



1) The firmware update of the dac8 Stereo will be uploaded over USB. Some streaming software/network players that you will be able to install on the Raspberry Pi have their own "over the air" update functionality, which does not concern dac8 Stereo firmware.

2) The output voltage is set with tiny, high-precision resistors on the DAC board, so unfortunately, there is no simple way to change the output voltage later on. For this level of performance, the layout needs to be as tight as possible, so trimmers or switches are not an option.

Thank you for your reply and information.

The credit card purchase option was never enabled on the website, and only EU buyers were able to buy the DAC8 Stereo. It seems that again Okto is overwhelm with orders (apparently from the EU), and at the moment it is not being offered at all. When will it be available to buy again? Will credit card orders be enabled then?

 

[jjk]

Drool.
VanityHD/103 seems like THE perfect solution for a mixed audio/HT system (PC audio only USB + Bluray/streamer stick HT via AES)!
You wouldn't happen to have a spare Vanity card, would you?
Seriously, though, would you happen to have an email address for AudioPraise? Their website only lists a phone number....
My guess is that you'll be astounded by the OktoDAC when it arrives - best wishes!!

@Neddy
Sorry for the late reply.
I don't have another Vanity board. I actually feel fortunate as about a year ago I considered selling it. Happy that I didn't follow through!
I actually haven't employed it for two years or so. I tested it to make it sure it was still good before I ordered last month.
I used it initially to support 3 Gustard DACs for a 5.1 configuration (NUC>>Oppo>>Gustards). Worked just fine, I was happy.
But then I discovered I2S and changed my entire front end to a PinkFaun streamer with an I2S MCH bridge. Love it. PinkFaun>>2 Matrix Sabre Pros and a Topping DX7Pro.
I have ordered the Okto8 to replace my Emotiva XMC-1 in HT duties. Still undecided if I will use the AES/USB option or stick a miniDSP DDRC-88D in the middle. I will begin with option 1 and run my EQ/DSP through the streamer/JRiver. If needed, I can add the miniDSP.
If I really like it, I can also use it for Computer audio duties and eliminate the I2S and above 3 DACs. Or not.
Here is an Audiopraise email, which I think is still active. His name is also Pavel and he's a good dude. He is working on an I2S device and I have signed up to be a Beta Tester for him. [email protected]
Stay healthy and play it loud!

 

[crawf1982]

Here is an Audiopraise email, which I think is still active. His name is also Pavel and he's a good dude. He is working on an I2S device and I have signed up to be a Beta Tester for him. [email protected]

@jjk Do you have any further details on the I2S device Pavel is working on? Is it a standalone device, or something that is designed to work with the Oppo disc players? I tried looking on the Audiopraise website, but it seems to be down at the moment.

I fitted a Vanity203HD board in my Oppo 203 and I am using the I2S header to connect directly to a custom unit that Okto Research made for me (images below). The combination works flawlessly and enabled me to remove the AVR from my HT setup. It is such a shame that Oppo has discontinued its disc players.

 

[Veri]

@jjk Do you have any further details on the I2S device Pavel is working on? Is it a standalone device, or something that is designed to work with the Oppo disc players? I tried looking on the Audiopraise website, but it seems to be down at the moment.

I fitted a Vanity203HD board in my Oppo 203 and I am using the I2S header to connect directly to a custom unit that Okto Research made for me (images below). The combination works flawlessly and enabled me to remove the AVR from my HT setup. It is such a shame that Oppo has discontinued its disc players.

View attachment 59078

View attachment 59079

Wow those stack pretty neatly great set-up.

 

[crawf1982]

That was by design. We wanted to keep the ribbon cable run as short as possible. Luckily, the vent holes on the back of the player are just big enough for the ribbon cable to be fed through!