Review and Measurements of Okto DAC8 8Ch DAC & Amp

[Thomas savage]

What stops us from having a device like this but instead of the wired analogue outputs it sends out 8 channels of 24/96 remotely to little receiver units that can be plugged directly into powered speakers , amps and subs?

These little receivers could be battery powered , you need 4 buy 8 and you have a charging unit in a cupboard. Simply replace the unit like a lightbulb as and when.

Software in the main unit would take care of all synchronisation and delay issues as well as room EQ automatically. Enabling one as much placement freedom as possible and a wide variety of speaker end point variation to be taken into account.

Is the problem one of standardisation wrt the wireless transmission? Is that what we are waiting for as as far as I know it's technically possible and not overly expensive to do.

 

[Kal Rubinson]

What stops us from having a device like this but instead of the wired analogue outputs it sends out 8 channels of 24/96 remotely to little receiver units that can be plugged directly into powered speakers , amps and subs?
..............................................................
Is the problem one of standardisation wrt the wireless transmission? Is that what we are waiting for as as far as I know it's technically possible and not overly expensive to do.

WiSA.

Also, if you do not insist on wireless, I am using a miniDSP U-DIO8 to send AES3 to the Dutch&Dutch 8c.

 

[Dominique-T]

Hello everyone,

first of all, thank you for all the feedback, we really appreciate it. I hope I will be able to answer most of your questions in this post.

DAC8 Stereo is going to contain Raspberry Pi in a same way the DAC8 DSP is. We will specify it more clearly on the website.


If you sent us a message, please be patient, as we received a crazy amount of them and will be answering for multiple days.

Thank you all,
Pavel Krasensky, Okto Research

Dear Pavel,

Could you explain how the RPI is connected to the DAC, USB or I2S?

Dominique

 

[rickyhgarcia]

Please help me understand how this unit is connected to my home rig...kind of new into the "separates" digital world of audio. I was about to put my money into an RME ADI-2 DAC, but Amir´s test results, his "highly" recommendation for this product, and being at about the same price point, it is a must that this product is considered.

There are two models currently on the available list from this company, PRO and Stereo. The PRO lists a USB plus four (4) AES/EBU inputs, and eight (8) XLR balanced analog outputs. The Stereo is more like what is available from other vendors with USB, AES/EBU, Optical and SPIDF inputs, and two stereo XLR balanced analog outputs.

So, does each pair of XLR balanced outputs on the PRO correspond to each AES/EBU input? If so, does this means that one of these pairs must be programmable to take either the USB or its corresponding AES/EBU input? And, if this is the case, internally the PRO unit is simpler because is does not require a switch to select which input to output, and internal cicuitry to connect each inputs DAC output to one analog pair of outputs, hence the lower price? Is this simplicity better for performance, since less internal signal manipulation is required?

Mostly DAC are used to incorporate PC's and digital disks transports to an analog stereo system. The PC has USB outputs, so no problem there. However, most digital disk transports uses Optical (Toslink) or RCA SPIDF outputs. Can a digital cable be made as RCA to AES/EBU without compromising the signal quality?

The RME ADI-2 DAC has probably hundreds or thousands of units in the market, so its reliability is well known. With the Okto units, we only know about the prototype tested by Amir. Comments??

 

[MSNWatch]

Please help me understand how this unit is connected to my home rig...kind of new into the "separates" digital world of audio. I was about to put my money into an RME ADI-2 DAC, but Amir´s test results, his "highly" recommendation for this product, and being at about the same price point, it is a must that this product is considered.

There are two models currently on the available list from this company, PRO and Stereo. The PRO lists a USB plus four (4) AES/EBU inputs, and eight (8) XLR balanced analog outputs. The Stereo is more like what is available from other vendors with USB, AES/EBU, Optical and SPIDF inputs, and two stereo XLR balanced analog outputs.

So, does each pair of XLR balanced outputs on the PRO correspond to each AES/EBU input? If so, does this means that one of these pairs must be programmable to take either the USB or its corresponding AES/EBU input? And, if this is the case, internally the PRO unit is simpler because is does not require a switch to select which input to output, and internal cicuitry to connect each inputs DAC output to one analog pair of outputs, hence the lower price? Is this simplicity better for performance, since less internal signal manipulation is required?

Mostly DAC are used to incorporate PC's and digital disks transports to an analog stereo system. The PC has USB outputs, so no problem there. However, most digital disk transports uses Optical (Toslink) or RCA SPIDF outputs. Can a digital cable be made as RCA to AES/EBU without compromising the signal quality?

The RME ADI-2 DAC has probably hundreds or thousands of units in the market, so its reliability is well known. With the Okto units, we only know about the prototype tested by Amir. Comments??

If the RME works for your needs then buy it. You will NOT hear an audible difference between these units even if the Okto measures marginally better.

 

[amirm]

The RME ADI-2 DAC has probably hundreds or thousands of units in the market, so its reliability is well known. With the Okto units, we only know about the prototype tested by Amir. Comments??

I can only speak to DAC8 Pro version (not stereo). Here, you get 8 analog outputs in XLR format which you don't get with ADI-2. So if one day you want to go from stereo to multichannel music, you can. The menus are also a delight to use in DAC8 compared to obscure ones in ADI-2. The DSP version also removes clutter by including such in the unit for streaming.

 

[rickyhgarcia]

I can only speak to DAC8 Pro version (not stereo). Here, you get 8 analog outputs in XLR format which you don't get with ADI-2. So if one day you want to go from stereo to multichannel music, you can. The menus are also a delight to use in DAC8 compared to obscure ones in ADI-2. The DSP version also removes clutter by including such in the unit for streaming.

Amir...what signal comes out of the 8 channels? Does each pair of channels correspond to each AES/EBU input in the production product? The prototype you tested only have one USB input...so, in the tested unit, the same output is repeated four times?

 

[amirm]

Amir...what signal comes out of the 8 channels? Does each pair of channels correspond to each AES/EBU input in the production product? The prototype you tested only have one USB input...so, in the tested unit, the same output is repeated four times?

I don't have one with AES/EBU so can't comment on that. On USB, the device exposes 8 channels of audio. By default audio apps send their stereo signals to channels 1 and 2. So that is how the routing works (i.e in software, not hardware).

 

[Leon]

Dear Amirm

Several questions are related to the quality of the digital volume managed by the SABRE 32 bits. Is it possible that you do a SINAD measurement with a 25db less vs 100% volume in order to compare the result?

A better approach will be to detect the volume decrease value when the SINAD is less goos vs 100% of volume !

Thank you

Hervé

 

[JohnYang1997]

Dear Amirm

Several questions are related to the quality of the digital volume managed by the SABRE 32 bits. Is it possible that you do a SINAD measurement with a 25db less vs 100% volume in order to compare the result?

A better approach will be to detect the volume decrease value when the SINAD is less goos vs 100% of volume !

Thank you

Hervé

I don't think it matters in this case. The noise is extremely low even when it's not attenuated, meaning, you can even use software volume control and won't experience degradation in sound quality.

 

[Leon]

Yes, I think so but measurement could definitively close questions/feeling/advice: objective results is better than subjective ;-)

 

[pos]

There is no practical difference between ESS' integrated volume control and a properly implemented software volume control.
As mentioned by @JohnYang1997 the residual noise of the DAC will stay the same, meaning you will loose 10dB or dynamic range when reducing volume by 10dB.
You have to decide if this level of residual noise is low enough for your application, ie considering the gain of your amps, the sensitivity of your drivers, your listening distance, etc.

 

[amirm]

Dear Amirm

Several questions are related to the quality of the digital volume managed by the SABRE 32 bits. Is it possible that you do a SINAD measurement with a 25db less vs 100% volume in order to compare the result?

A better approach will be to detect the volume decrease value when the SINAD is less goos vs 100% of volume !

Thank you

Hervé

I have already returned the unit.

 

[Leon]

OK Amirm

If you have the possibility to test the Sabre 32 bits volume control with another DAC ( ie : oppo 205) it will be very appreciated.

Thank you and congratulation again for yours tests on DAC with always a high level of exhaustive/quality measurements !

 

[Okto Research]

Attaching a RPI to the dac is a great idea. I suppose the connection will be done using I2S?

Connection is done using I2S in DAC8 DSP (while Raspberry is an I2S slave) and using USB in DAC8 Stereo (since it is the only way to output DSD from the Raspberry).

@Okto Research , I believe the current design supports either 110v or 220v. Would you make a version to support BOTH voltages (maybe a switch at the back)? It would be much more convenient for people who need to relocate frequently.

Sorry, we don't plan that at the moment. Customers are going to receive their units set to a voltage according to the country they live in.

does it do MQA ? Just curious not a deal breaker.

No, we don't see much need for supporting it, neither we do for the sole existence of it. It surely saves some internet bandwidth over FLAC, but since Google just announced they are going to mass-stream computer games...

Hi, what are the planned formats and sample rates supported for the DAC ethernet input, with the Pi?

Raspberry Pi in DAC8 DSP resamples its output to 96kHz/24bit (the internal sample rate of the DSP portion), which is why it supports all the sample rates that Volumio player does on the ethernet input. I haven't found that specified on their website, but I believe it doesn't end with 384kHz. DAC8 Stereo is going to accept sample rates up to 384kHz (we reserve room for change here as we are working on that design).

So, does each pair of XLR balanced outputs on the PRO correspond to each AES/EBU input? If so, does this means that one of these pairs must be programmable to take either the USB or its corresponding AES/EBU input? And, if this is the case, internally the PRO unit is simpler because is does not require a switch to select which input to output, and internal cicuitry to connect each inputs DAC output to one analog pair of outputs, hence the lower price? Is this simplicity better for performance, since less internal signal manipulation is required?

There are two 8-channel inputs on the DAC8 PRO that can be switched between - USB and 4xAES/EBU. With USB input selected, it works as an 8 channel USB interface with one to one channel mapping, with AES/EBU selected, each AES/EBU input corresponds to one output channel pair. The lower price of the PRO version is due to the lack of Raspberry Pi and the streaming capabilities (as there is not much need for it in a pro/semi-pro environment).

The RME ADI-2 DAC has probably hundreds or thousands of units in the market, so its reliability is well known. With the Okto units, we only know about the prototype tested by Amir. Comments??

But with products like this one. You don't know how solid it is, how reliable they are, how long they will go on. It could easily be that they fold in a couple of months and then you can have a very expensive coaster if there is something wrong.

Every company has once been small and if no one ever bought anything from a small company, there would be no companies. The only thing I can do to convince you that our products are a real deal is to suggest you to participate in DAC8 tour and see/hear for yourself. We believe this is only fair. We also think it is more valuable to judge the audio equipment in a home listening environment which you know well and are used to, so you can tell the difference better.

 

[amirm]

If you have the possibility to test the Sabre 32 bits volume control with another DAC ( ie : oppo 205) it will be very appreciated.

Thank you and congratulation again for yours tests on DAC with always a high level of exhaustive/quality measurements !

My pleasure. I do plan to study the topic of volume controls, examining the effects of everything from software volume controls to hardware and analog.

 

[jtwrace]

There are two 8-channel inputs on the DAC8 PRO that can be switched between - USB and 4xAES/EBU. With USB input selected, it works as an 8 channel USB interface with one to one channel mapping, with AES/EBU selected, each AES/EBU input corresponds to one output channel pair. The lower price of the PRO version is due to the lack of Raspberry Pi and the streaming capabilities (as there is not much need for it in a pro/semi-pro environment).

So if one wants 8ch of output and be able to use Roon (convolution filter from Audiolense) which device is the one to get?

 

[nm4711]

Several questions are related to the quality of the digital volume managed by the SABRE 32 bits. Is it possible that you do a SINAD measurement with a 25db less vs 100% volume in order to compare the result?

At first read post #172. pos is perfectly right. The dynamic range will decrease when reducing the volume, because the noise floor stays the same.
So ideally you set the amps gain, so that you are at your max listening level when the DAC is set to -0 dB attenuation.

I did it this way in my setup with a DAC8 module and I cannot hear any noise at my listening position. And as long it is this way, there shouldn't be any audible degradation of the sound quality when using digital volume control.

 

[JohnYang1997]

The dac has 2.6uV rms noise according to measurements. It's at the lowest range of anything. NONE of the speaker amplifiers has this low noise. And it's at the same level of the best headphone amps' output stages.

 

[777]

The noise at the speakers will be 2.6uV x closed loop amplifier gain (30x for example). So, the noise will be aprox. 80uV at the acoustic transducer. You can hear that noise only if you stick the ear by the tweeter. It is very weak level of the noise. The most probably the amplifier noise will be dominant, will be the strongest.