Review and Measurements of Okto DAC8 8Ch DAC & Amp

[Bliman]

I used a miniDSP 2x4HD before and then 3 20$ ES9023 based DACs, both unbalanced.

Regarding the sound: I have never heard them in direct comparison, there were two weeks between. Furthermore this really is a subjective topic, so I don't want to comment on the sound. What I can say is, that none of those DACs sounded bad to me back then.

But the noise coming from the Okto DAC8 is defenetly much lower. This is important to me, because I'am using digital volume control. With the DAC8 there is really no reason for an analog preamp anymore. So I don't want to miss the DAC8.

Thank you

 

[DWPress]

I use the Digi-FP and the Vol-FP. You can't connect S/PDIF directly to the miniSHARC, because the onboard input on J2 header is TTL level. So you need a converter from S/PDIF level to TTL level. On the same header are the I2S outputs I connected to the DAC8.

I'm still not clear on the connection. I don't have a miniSHARC but I do have a MiniDSP4x10 with the Digi & Vol-FP boards. Would I need some additional kit to get a signal to the DAC8? I'm looking to eliminate the 4x10 from my system so wouldn't have I2S out to connect with. Hoping to just go from a computer to the DAC8 somehow and spdif would be easiest to start with.

Even with the balanced to unbalanced conversion the SNR would be totally acceptable and out perform the current amps abilities let alone the speakers so that's not an issue for me.

 

[nm4711]

I'm still not clear on the connection. I don't have a miniSHARC but I do have a MiniDSP4x10 with the Digi & Vol-FP boards. Would I need some additional kit to get a signal to the DAC8? I'm looking to eliminate the 4x10 from my system so wouldn't have I2S out to connect with. Hoping to just go from a computer to the DAC8 somehow and spdif would be easiest to start with.

I think now I understand what you mean. You don't want to use a DSP anymore, but connect the PC directly to the DAC? I'am not sure if you can connect S/PDIF directly to the board, probably not? You cannot use Digi-FP. It communicates over I2S with the DSP and needs a BCLK and LRCLK. Furthermore S/PDIF is only 2 channel. So you would need 4 S/PDIF outputs from your computer. The best way is to use an USB interface with 8 channel I2S out to the DAC, or just buy the DAC8 PRO.

 

[DWPress]

@nm4711, thanks for clarifying. Doesn't look like the best fit for my needs after all then. I'm still going to use DSP but via Roon for convolution to take care of the active XO and room EQ. I no longer wish to be tied to the MiniDSP ecosystem with it's limitations and the DAC8 Pro is overkill feature wise for me though a very attractive package. Looks like I'm back to the pro boards like a Motu Ultralight MK IV.

 

[chezalfreo]

@Okto Research, I am eager to hear from you about the ongoing DAC8 PRO modifications

I would be really interested too @Okto Research

 

[Bliman]

Sorry I have a question again.
I was looking at the Crane Song Solaris http://www.cranesong.com/SOLARIS.html.
And it states this.

"The reference clock has less then 1pS and a proprietary reconstruction
filter for accurate time domain response.

The clock's jitter measured from 10Hz to 20KHz is typically 0.045pS."

Is there anywhere where I can find these measurements on the graphs here on the Okto Research?
I see that we have a jitter noise graph, but I don't know if you extrapolate this information out of it.
And I know that the Grace Design also had a special locking "s-locktm dual stage PLL (phase lock loop) circuitry for the ultimate in low jitter digital signal stability •and sonic integrity. "
Does the Dac 8 stereo also have something like this?
Again sorry for the questions.
To be honest I would like to have much more information on the site.
I don't want to come over as a d*ck.

 

[amirm]

"The reference clock has less then 1pS and a proprietary reconstruction
filter for accurate time domain response.

The clock's jitter measured from 10Hz to 20KHz is typically 0.045pS."

Is there anywhere where I can find these measurements on the graphs here on the Okto Research?

What graph? You are stating a set of numbers which are useless marketing techno-talk. The graph you want is in every one of my reviews which hardly any manufacturer provides.

The measurements stated above are what is fed to the DAC chip internally, not what comes out of it as impact on audio. Mine shows that.

 

[Bliman]

What graph? You are stating a set of numbers which are useless marketing techno-talk. The graph you want is in every one of my reviews which hardly any manufacturer provides.

The measurements stated above are what is fed to the DAC chip internally, not what comes out of it as impact on audio. Mine shows that.

Thank you what I am referring to is on this review page https://www.audiosciencereview.com/...-8ch-dac-amp.7064/#lg=attachment23771&slide=0
This is so confusing.
So if I am correct the measurements I gave from the Crane song site. Are measurements they take before it is outputted?
I see that your graph works with dBrA and above they work with time? Isn't that different?
I also thought that the locking was important for jitter. I thought that jitter was a timing thing?
Like explained here

Sorry for my ignorance.

 

[amirm]

Thank you what I am referring to is on this review page https://www.audiosciencereview.com/...-8ch-dac-amp.7064/#lg=attachment23771&slide=0
This is so confusing.
So if I am correct the measurements I gave from the Crane song site. Are measurements they take before it is outputted?
I see that your graph works with dBrA and above they work with time? Isn't that different?
I also thought that the locking was important for jitter. I thought that jitter was a timing thing?

It is a timing thing. Once converted to its impact on analog output of the DAC, it creates new frequencies which show up in my test. My measurements show you the nature of those frequencies. There can be one, or many. They can be one frequency or many.

And yes, all of my measurements are taken from the output of the DAC.

The other companies take the single number summary of jitter (irrespective of its nature) that is used to drive the DAC chip. Those aberrations do not a) necessarily travel to the outside of the dac and b) there are other sources of jitter and unwanted frequencies beside the clock. Again, my test includes all that is there including (b).

In all respects do not think of effect of jitter as timing/echo/smear, etc. The numbers we are talking about are infinitely small for your hearing to detect them such. It is best to think of them as unwanted distortions as my graph shows.

 

[Bliman]

It is a timing thing. Once converted to its impact on analog output of the DAC, it creates new frequencies which show up in my test. My measurements show you the nature of those frequencies. There can be one, or many. They can be one frequency or many.

And yes, all of my measurements are taken from the output of the DAC.

The other companies take the single number summary of jitter (irrespective of its nature) that is used to drive the DAC chip. Those aberrations do not a) necessarily travel to the outside of the dac and b) there are other sources of jitter and unwanted frequencies beside the clock. Again, my test includes all that is there including (b).

In all respects do not think of effect of jitter as timing/echo/smear, etc. The numbers we are talking about are infinitely small for your hearing to detect them such. It is best to think of them as unwanted distortions as my graph shows.

First thank you for explaining.
Is there a youtube video that can also explain it to me? Because I still have major difficulty of understanding it ?
The way I understand it from you is this. You play a signal from the analyzer through the dac. You then receive the signal back but you eliminate the frequencies you send to it and measure the ones that are left over that the Dac created itself.
I hope this is right?
But with that I still don't get the timing of it all.
Or is it the timing that is creating this noise and frequencies on the graph?
The summary thing I can't make sense of.
If someone can post a video to explain it that would be great. Because I don't want to hold up amirm to much.

 

[amirm]

The way I understand it from you is this. You play a signal from the analyzer through the dac. You then receive the signal back but you eliminate the frequencies you send to it and measure the ones that are left over that the Dac created itself.
I hope this is right?

No. The original frequency is also there. It is the tall spike in the middle:

But with that I still don't get the timing of it all.
Or is it the timing that is creating this noise and frequencies on the graph?

Correct. It is a mathematical concept that doesn't lend itself to easy explanation. Just accept that if you take that center tone and change the timing of it, you wind up with a pair of tones on each side indicating that if they are sine waves. This is called modulation. It is how AM and FM radio work.

There are no youtube videos on this.

 

[Bliman]

No. The original frequency is also there. It is the tall spike in the middle:

Correct. It is a mathematical concept that doesn't lend itself to easy explanation. Just accept that if you take that center tone and change the timing of it, you wind up with a pair of tones on each side indicating that if they are sine waves. This is called modulation. It is how AM and FM radio work.

There are no youtube videos on this.

Thank you for the explanation.

 

[Bliman]

Ok I am of course searching as much information as possible about the stereo Dac. Because it could be my next purchase in the search for audio Nirwana.
I am in a sort of dilemma, I don't dare to ask many more things here and also not to Okto Research of the fear of coming over as asking way to many things.
But here goes. I was comparing it to the Benchmark audio dac3 both in the reviews here and also in documentation.
Now on the features list of the Benchmark you can read this
"
Direct Connectivity to Power Amplifiers

Benchmark DAC1, DAC2, and DAC3 converters are designed to directly drive power amplifiers and speakers. Benchmark converters feature adjustable low-impedance passive attenuators at the XLR outputs that can be used to optimize the interface to the power amplifier (or powered monitor). This unique Benchmark feature optimizes the gain staging between the DAC and the power amplifier. Proper gain staging cannot be overemphasised. When audio stages are properly matched, each component in the audio chain is able to operate at its optimum signal level, and the system performance is significantly improved.

"
Now I would connect the Dac8 straight to my lyngdorf sda 2175 poweramplifier with balanced XLR outputs.
Does anyone know that the Stereo Dac 8 also has something like the above?

 

[BYRTT]

...Now I would connect the Dac8 straight to my lyngdorf sda 2175 poweramplifier with balanced XLR outputs.
Does anyone know that the Stereo Dac 8 also has something like the above?

Take a look at their website, standard outputs spec is now changed to 4V RMS differential or per request up to 15V RMS. If down the road one needs output set to other level then one can diy in change a couple of resistors or one can hire a local tech company to change those components. Will guess if you go under module (diy) on their website and download its manual that you can see procedure to set various output levels.

 

[Bliman]

Take a look at their website, standard outputs spec is now changed to 4V RMS differential or per request up to 15V RMS. If down the road one needs output set to other level then one can diy in change a couple of resistors or one can hire a local tech company to change those components. Will guess if you go under module (diy) on their website and download its manual that you can see procedure to set various output levels.

Thank you. Can I calculate what the best V RMS would be with my power amplifier? And how would you do that?

 

[chezalfreo]

Thank you. Can I calculate what the best V RMS would be with my power amplifier? And how would you do that?

I'm pretty sure you could have found the manual too http://lyngdorf.com/wp-content/uploads/2017/09/SDA-2175-Owners-Manual.pdf.
It is written Input sensitivity 2 V at 8 Ohms.
As long as the output level of the DAC is > to the input sensitivity of your amplifier, you will be able to get full output from the amp, therefore you're good to go.

 

[Bliman]

I'm pretty sure you could have found the manual too http://lyngdorf.com/wp-content/uploads/2017/09/SDA-2175-Owners-Manual.pdf.
It is written Input sensitivity 2 V at 8 Ohms.
As long as the output level of the DAC is > to the input sensitivity of your amplifier, you will be able to get full output from the amp, therefore you're good to go.

Thank you. Yeah finding the manual is no problem.
Knowing which numbers to look at is a whole different ballgame.
My speakers are 4 ohm. I guess that I don't have to look at that? So anything above 2V is good? So I don't have to ask to adjust anything right?

 

[BYRTT]

@Bliman, a note is 4 ohms verse 8 ohms load need half the voltage to burn the same wattage and draws double the amps compared to 8 ohms, hope below links can help a bit clear the picture, its some neat calculators (fomula wheels) for electrics plus acoustics, that said you not lost with whatever output level you order for this unit in it can alway be changed down the road solder some other resistor values into unit:

http://www.sengpielaudio.com/calculator-ohm.htm

http://www.sengpielaudio.com/calculator-ak-ohm.htm

And here is main index for all their neat audio calculators at that site:

http://www.sengpielaudio.com/Calculations03.htm

 

[edechamps]

My speakers are 4 ohm. I guess that I don't have to look at that?

The impedance of your speakers is an issue for the amplifier, not the DAC. The DAC will only see the input impedance of the line level input of the amplifier, which is typically very high (>1 KΩ).

 

[Bliman]

The impedance of your speakers is an issue for the amplifier, not the DAC. The DAC will only see the input impedance of the line level input of the amplifier, which is typically very high (>1 KΩ).

But the dac also operates preamplifier for me..