Review and Measurements of Okto DAC8 8Ch DAC & Amp

[BDWoody]

According to what I've been able to understand about the Okto DAC8 Pro and its current possible implementations in such a setup, one pathway might be the following: miniDSP U-DI08 to a miniDSP Dirac DDRC-88D, then then to the Okto, and then directly to a balanced multichannel amplifier. Is this at least one pathway that some of you who are interested in this Okto plan to implement it?

- john

I had been looking at the Okto as you described, but after purchasing the JBL 708p's and 705p's, I am leaning towards using step one and two above, and just go digital direct from the DDRC-88D to the AES digital input on the speakers. Would be all digital until it hits the speaker. Without active speakers or amp with digital in, the Okto or multiple other DAC's would have to get in the path somewhere.

 

[Fledermaus]

Server output direct to DAC8 with all DSP in software.
.

Sorry to be late at catching up - so you address your n pre-processed digital channels to the n channel DAC, that in turn sorts them out, converts and sends each of them to the appropriate analog channel ? If so, how is the sorting done, or : is there a way to assign a channel number in sofware that is recognized by the DAC which then sends it to the intended output ?

 

[g29]

Sorry to be late at catching up - so you address your n pre-processed digital channels to the n channel DAC, that in turn sorts them out, converts and sends each of them to the appropriate analog channel ? If so, how is the sorting done, or : is there a way to assign a channel number in sofware that is recognized by the DAC which then sends it to the intended output ?

Same way you do it for left and right channels, but using more channels. Specific software implementation details varies from manufacturer to manufacturer (e.g. some software may allow channel renaming, some may not, GUI deltas, etc.).

JRiver Media Center uses channel mapping or channel routing.

JRiver Media Center Channel Mapping Thread
JRiver Media Center Channel Routing Thread

Here is an example in JRiver Media Center to make a stereo high pass and low pass XO at 80Hz (stereo biamping) using the left, right, center and sub (3.1) channels.

The Left and Center channels get the same signal (left channel duplicated on center).
The Right and Sub channels get the same signal (right channel duplicated on sub).
The Left and Right channels are assigned the same high pass filter. (high frequency channels).
The Center and Sub channels are assigned the same low pass filter. (low frequency channels).
The Center and Sub channels are assigned the same gain boost. (level balancing).

(wash, rinse, repeat for 6/triamping/5.1 and 8/quadamping/7.1 channels)

 

[somebodyelse]

Same way you do it for left and right channels, but using more channels. Specific software implementation varies from manufacturer to manufacturer. JRiver Media Center uses channel mapping or channel routing.

Similarly linux has several ways to map channels and apply filtering for crossover and/or room correction. Some are point-and-click and others require editing text config files.

 

[Kal Rubinson]

Sorry to be late at catching up - so you address your n pre-processed digital channels to the n channel DAC, that in turn sorts them out, converts and sends each of them to the appropriate analog channel ? If so, how is the sorting done, or : is there a way to assign a channel number in sofware that is recognized by the DAC which then sends it to the intended output ?

As the other guys described.

 

[ppataki]

Does anybody here already actually own an Okto Research DAC8 Pro? Would be interested in knowing if it sounds as good as it measures
Many thanks

 

[Labjr]

I'd love to see a great DSP crossover for the Linkwitz LX521 and other multi-driver systems. However, I'm not sure there's anything out there that will outperform an analog active crossover yet. Basic DACs are only now getting to the point where the distortion is inaudible. Digital audio is different than analog distortion, where it takes only a small amount of distortion to sound nasty and unnatural. Trying to do a multi-way crossover in real time using DSP would seem like a real engineering challenge to get it right. Hopefully, some of these new smaller manufacturers will surprise us with innovation in that area. I do wonder if there's enough demand for that to happen.

 

[JP]

Interesting learning from setting up the DAC8 DSP with LXmini+2: have to pay attention to the extremes. I'd copied over the settings from the miniDSP 4x10HD to the nanoSHARC. Everything seemed fine except for bass heavy tracks where I had massive distortion. I noticed the sub channels were outputting over 0dBFS which was the cause. As the nanoSHARC has no volume control everything is running full-bore, while the volume control for the 4x10 is done in the DSP.

Previously I'd thought the subs were reaching their max and distorting at higher levels, but it turned out I could get far more SPL out of them cleanly with the nanoSHARC setup. With my amps the 4x10 was exceeding 0dBFS with certain tracks when the volume was higher than ~-15dB. Makes me wonder how many other people are bumped in to that implementation issue and don't know it.

 

[audimus]

Does anybody here already actually own an Okto Research DAC8 Pro? Would be interested in knowing if it sounds as good as it measures
Many thanks

If it works as measured in a real scenario, you would hear nothing good or bad you can attribute to it.

However, there will be plenty of people aware of the measurements and/or price saying it shows a greater level of clarity, detail, transparency, dynamicism, etc. Unless that is with respect to a really poor DAC, such claims have as much a chance of being influenced by expectation bias as legitimately hearing anything positively.

 

[vinjoutw]

I realize this is one of the the possible great implementations of this DAC. This is a highly evolved use of this DAC, and that's admirable. But I'm not quite there, yet -- still personally interested in just a multichannel implementation. However, when you say active 3-way speakers, I'm assuming you will be using the speakers' internal active crossover engine for processing and then the 2 subs - so you would be using only 4 of the 8 channels, or am I not understanding you? If different from this, I am still quite interested in what you might be intending on using as an external 3-way crossover processor/engine. In any case, this sounds like a very good setup, so wishing you great listening!

- john

Actually I pre-ordered one Okto DAC8 pro to do a quad-amping for a 4 way speaker. I am using D-channel's PureMusic software on MAC which has digital crossover feature that is capable of adjusting sound level and channel delay to 0.01ms level for time alignment.

I tried to use 4 sets of stereo DACs (TEAC UD-503) to do this, but it was too many problem with clock synchronization.

 

[g29]

... I am using D-channel's PureMusic software on MAC which has digital crossover feature that is capable of adjusting sound level and channel delay to 0.01ms level for time alignment.

I tried to use 4 sets of stereo DACs (TEAC UD-503) to do this, but it was too many problem with clock synchronization.

Were you using their USB inputs or their S/PDIF inputs ?

 

[MWC]

Were you using their USB inputs or their S/PDIF inputs ?

Either way (USB or S/PDIF) the synchronization problems would exist. One would need some kind of master clock tying them all together.

 

[somebodyelse]

Either way (USB or S/PDIF) the synchronization problems would exist. One would need some kind of master clock tying them all together.

Something like the nanoDIGI or RME Digiface that has multiple spdif outputs sharing a clock source would do the trick.

 

[Kal Rubinson]

Either way (USB or S/PDIF) the synchronization problems would exist. One would need some kind of master clock tying them all together.

The U-DIO8 should do that.

 

[g29]

The U-DIO8 should do that.

The U-DIO8 with 4 Khadas Tone Board DACs might be a budget solution and step up over the U-DAC8.

@Kal Rubinson , When you reviewed the U-DIO8, did you ever test it in a stereo bi/tri/quad amp configuration in addition to multi-channel ?

 

[Kal Rubinson]

The U-DIO8 with 4 Khadas Tone Board DACs might be a budget solution and step up over the U-DAC8.

@Kal Rubinson , When you reviewed the U-DIO8, did you ever test it in a stereo bi/tri/quad amp configuration in addition to multi-channel ?

Nope. Not feasible for me.

 

[somebodyelse]

The U-DIO8 with 4 Khadas Tone Board DACs might be a budget solution and step up over the U-DAC8.

Apparently the Tone Board was designed with stacking in mind to allow 5.1 or 7.1 output from 3 or 4 of them, although it doesn't seem to have happened in the end. This combination isn't exactly a budget solution - it's about the price of a MOTU 8A.

 

[Labjr]

Apparently the Tone Board was designed with stacking in mind to allow 5.1 or 7.1 output from 3 or 4 of them, although it doesn't seem to have happened in the end. This combination isn't exactly a budget solution - it's about the price of a MOTU 8A.

How does the MOTU perform?

 

[vinjoutw]

Either way (USB or S/PDIF) the synchronization problems would exist. One would need some kind of master clock tying them all together.

Teac UD-503 has external word clock input feature, so I used TEAC CG-10M (with 4 identical outputs) to link four UD-503 for synchronization.

However, this configuration has problem to work with MAC OS and PureMusic software.

 

[somebodyelse]

How does the MOTU perform?

@March Audio tested the 8A and Ultralite mk4 and both seem pretty good. If you use linux check https://linuxmusicians.com for the latest on compatibility issues as UAC mode behaviour changes with firmware version.