Okto 8 Owner’s Thread

[Vasr]

Hello Vasr,
OK, now I understand that you would like to have some switching/distribution mechanism in speaker level signals after the amplifiers.

Thanks! You have done the hard work of confirming my intuition about signal degradation. It is not that I want to switch at speaker levels, but there doesn't seem to be a solution if two amps need to drive the same set of speakers.

The alternative that will work is to get a stereo power amp with gain control and integrate that into HT by gain matching just like one would with a sub (most of which come with a gain control) in the analog domain. Then use the Stereo amp for HT as well. I don't know of any good stereo amps outside the pro world with gain control.

The other option to use a stereo amp without gain control for HT is to buy a stereo amp that has equal or greater gain than the HT amp and do the correction in digital domain so you are only attenuating the L and R going via the stereo amp to match the output sound levels rather than match the gain between the two amps. Otherwise, it would potentially digitally clip if it was the other way around, especially if the gain difference was significant.

But not sure input sensitivity wouldn't be an issue here and reduce the dynamic range for the L and R with that attenuation correction.

Will research more. In any case, this is going beyond the Okto scope so I will end further discussion on this here. Doesn't look like there is an off-the-shelf solution for the switching.

 

[waynel]

Thanks! You have done the hard work of confirming my intuition about signal degradation. It is not that I want to switch at speaker levels, but there doesn't seem to be a solution if two amps need to drive the same set of speakers.

The alternative that will work is to get a stereo power amp with gain control and integrate that into HT by gain matching just like one would with a sub (most of which come with a gain control) in the analog domain. Then use the Stereo amp for HT as well. I don't know of any good stereo amps outside the pro world with gain control.

The other option to use a stereo amp without gain control for HT is to buy a stereo amp that has equal or greater gain than the HT amp and do the correction in digital domain so you are only attenuating the L and R going via the stereo amp to match the output sound levels rather than match the gain between the two amps. Otherwise, it would potentially digitally clip if it was the other way around, especially if the gain difference was significant.

But not sure input sensitivity wouldn't be an issue here and reduce the dynamic range for the L and R with that attenuation correction.

Will research more. In any case, this is going beyond the Okto scope so I will end further discussion on this here. Doesn't look like there is an off-the-shelf solution for the switching.

there is no issue with almost any power amp as the Okto DAC8 pro will put out 4.2V which is enough to clip 99%+ of amps. Just pick the stereo amp you want and use the Okto level adjustment or your software to compensate for gain differences. Remember , you’ll need to compensate for speaker sensitivity differences anyway. As I explained via PM you could just choose almost any stereo amp you want and always use it to drive the L and R speakers, there are plenty of places (PC , dac) where you can get the levels lined up.

 

[dualazmak]

OK, well understood.

I highly recommend you to consider the use Hi-Fi grade nice "integrated amplifiers" as "amplifiers" in your system. Nowadays, you have various choices of very nice "integrated amplifiers" having volume (as gain), L&R balance control, RCA and XLR inputs, two sets of stereo speaker outputs (SP-A and/or SP-B), pre - power separation mode, loudness compensator, etc., etc.

I have been still considering to use nice stereo "integrated amplifiers" even in my Hi-Fi multichannel project, since I am using ACCUPPHASE E-460 Integrated Amplifier in my reference audio system, and I am very much satisfied with E-460 in functionalities and sound quality.

Even though I am now exploring and testing various multichannel power amplifiers in my project, I have not yet fully excluded the possibilities of using "integrated amplifiers".

 

[Neddy]

@Vasr Interesting use case, thanks for the diagram!
A bit off your thought track, but I'm using a SurgeX AC power controller, which has 12v remote input and 3 banks of controllable AC outlets, which are programmable.
The OktoDAC provides the remote on/off control via it's remote, and I programmed the 3 banks (sub, LF, HF) amps to power up with 2sec delays between each.
So, it meets the 'simplicity of use' requirement.
That wouldn't solve your speaker switching problem however, though there might be a way to use the progammability/remote in/out features of the SurgeX to further control a speaker switcher....Hm....
Please report back when you find a neat solution - there has to be one; it's not that complex a task, and I've seen several DIY'd around various audio forums.

 

[waynel]

You need the HT amp for the additional channels when doing HT. So, it is the L and R speakers that are shared. If you are suggesting the stereo amp always doing the L and R even for HT which I mentioned above...

Other than the issue of having two amps both generating heat for both HT and Music, there is the same reason why you wouldn't use two different monoblocks for stereo when using both speakers. The gains need to be matched between the two amps for the level matching to happen (critically between LCR for HT) at all volume levels. Otherwise, HT experience will be out of whack. That constrains the stereo amp to only those that provide gain control. Most don't.

The Octo DAC Pro has a level adjustment which can compensate for gain differences between your multichannel amp and your stereo amp. You could also do this in software upstream. Either way this is not a problem.

 

[dualazmak]

The Octo DAC Pro has a level adjustment which can compensate for gain differences between your multichannel amp and your stereo amp. You could also do this in software upstream. Either way this is not a problem.

Yes, and let me add for sure for Vasr's kind attention and understandings.

OCTO DAC8PRO has independent gain control for each of the 8 channels, and also it has the master volume control. Once you would fix the relative gains in each of the 8 channels, of course you can control the master volume maintaining the relative gains for the 8 channels. And, "You could also do this in software upstream. Either way this is not a problem" as Waynel said.

 

[Vasr]

Thanks. Didn't realize the analog volume per channel balancing available on the Okto. That will work to match gains as long as having both on for HT use won't be a problem in heat generation.

 

[waynel]

Thanks. Didn't realize the analog volume per channel balancing available on the Okto. That will work to match gains as long as having both on for HT use won't be a problem in heat generation.

It’s not analog , it’s digital gain adjustment but it will work fine

 

[Vasr]

I was confused by this statement in the manual "The volume control is always applied to the analog outputs". I assume this just means then that digital outs via the AES/EBU or USB is not affected by the volume control. As in "Volume control only affects the analog outputs".

 

[dualazmak]

https://www.audiosciencereview.com/...nts-of-okto-dac8-8ch-dac-amp.7064/post-467112

 

[dualazmak]

https://www.audiosciencereview.com/...ssover-and-multichannel-dac.12489/post-440984

https://www.audiosciencereview.com/...ssover-and-multichannel-dac.12489/post-448875

 

[dualazmak]

And, DAC8PRO's high quality Headphone OUT is another line-level analog out of CH-1+CH-2 "under the control" of gain and master volume. If you like, you may use it as RCA unbalance OUT of CH-1+CH-2 with gain and volume applied.
https://www.audiosciencereview.com/...ssover-and-multichannel-dac.12489/post-420921

In DAC8PRO's Owners Manual, we can read;
Analog connectivity
Main outputs (back side)
8 x Neutrik gold-plated XLR connector
Output level: 4.1 V RMS differential full-scale
output impedance: 200 Ohms
Headphone output (front side)
6.3 mm (1/4”) TRS connector
Output level: 4.1 V RMS full-scale
120 mA linear output current
fixed to output channels 1 and 2
output impedance <100 mOhm

 

[waynel]

Feature requests( geared toward DAC8 pro but extendable to DAC8 stereo)

1) Initial On volume setting: I plan to use the auto on feature but it would be nice if there was a programmable volume setting that would be applied when the unit is turned on to prevent any surprises.

2) Direct remote commands: I plan to integrate the Okto DAC into my music/HT system which uses a logitech harmony hub. I use one button "watch a movie" or "listen to music" settings. Finite state machine based menus and remote schemes always cause problems when the device is not in the expected state. It would be nice to have dedicated universal remote commands that do the following regardless of where in the menu you happen to be:

Need to have:
On : turns on if off , stays on if on
Off: Turns off if on , stays off if off
Volume up: Always turns volume up regardless of menu state
Volume Down: Always turns volume down regardless of menu state

Nice to have
Mute: always mutes regardless of state, defeated by volume up
Input- USB - sets input to USB regardless of menu state or current input
Input - AES - sets input to AES regardless of menu state or current input

 

[Vasr]

I wish Okto would consider offering a choice of models of the 8 Pro - one with AES/EBU (for pro-audio applications) as in the current and another with 2 (or more) Optical/Coax TOSLINK inputs (from the Stereo version) instead for the consumer market. This would make it a great lightweight pre-amp covering a lot of use cases. Perhaps they will bring out a higher-tier version later.

For now, I am trying to figure out how the AES/EBU input (that will remained unused otherwise) may be used for accommodating one or more Optical sources.

Just adding one seems easy enough connectivity-wise using an Optical to AES/EBU converter like this one
https://www.amazon.com/Hosa-ODL-312-Converter-Discontinued-Manufacturer/dp/B000068OGR
to the input 1 mapped to channels 1 and 2.

Has anyone tried the above unit or something similar successfully?

The one unsatisfactory thing I see with the above if it works is not having a convenient one-button remote press to switch between the two - AES and XLR inputs. Working with the menu system is like working with a beautifully designed phone with flip-phone interface. Hopefully, a future firmware update will make this possible.

To accommodate more than one, this seems to do the trick along with the converter above

https://www.monoprice.com/product?p_id=13345

Its remote function can be mapped to a universal remote to switch as long as you can deal with the menu traversal in the Okto to switch between AES and XLR inputs.

I found this one that can switch between multiple TOSLINK inputs to AES out but with physical buttons and a DIY interface for a remote but way too expensive to consider and not sure it is any better than the converter/switch pair solution above if just Optical is fine.

https://www.rdlnet.com/product.php?page=449

 

[DrDardis]

Hi All,

Has anyone had any luck setting up the AES Okto -> PC -> USB Okto route?

I was experimenting with connecting a Nvidia shield into the DAC via USB/AES interface, then using the PC for DSP. The Shield is 16bit 48khz through it's usb. From the manual;

Because the UAC2 audio device is unable to change the USB host current sampling frequency, the DAC8 PRO will display a warning message if the sampling frequency of the received AES/EBU signal does not match the one selected by the USB host. It is up to the user to make the sample rate of the AES/EBU transmitting device match the sample rate of the UAC2 driver of the USB host.

Which I indeed encountered until I set the DIY ASIO driver to 16bit input/output. Then the warning was gone, and sound came through. The problem was - the sound was white noise.

I am using the UDIO-8 by minidsp to get the Shield audio (USB Audio Class 2) to the AES. AES channel 1 is meant to carry the clock. I am wondering if the interface is stuffing with that? Again, from the manual;

The DAC8 PRO offers 4 AES/EBU inputs that are free of resampling. That allows for a bitperfect playback by the DAC8 PRO as well as recording at the USB host side, but it also requires the inputs to be mutually synchronized and carry signals with matching sampling rates.

I suspect not, because if I play the shield through the DAC using pure AES, it sounds great. Clock must be getting through, right?

I do not know a lot about this stuff though, any help or advice is appreciated @Okto Research

 

[Vasr]

Hi All,

Has anyone had any luck setting up the AES Okto -> PC -> USB Okto route?

I was experimenting with connecting a Nvidia shield into the DAC via USB/AES interface, then using the PC for DSP. The Shield is 16bit 48khz through it's usb. From the manual;

Which I indeed encountered until I set the DIY ASIO driver to 16bit input/output. Then the warning was gone, and sound came through. The problem was - the sound was white noise.

I am using the UDIO-8 by minidsp to get the Shield audio (USB Audio Class 2) to the AES. AES channel 1 is meant to carry the clock. I am wondering if the interface is stuffing with that? Again, from the manual;

I suspect not, because if I play the shield through the DAC using pure AES, it sounds great. Clock must be getting through, right?

I do not know a lot about this stuff though, any help or advice is appreciated @Okto Research

Not a direct answer to your question but why not narrow down to the segment that is causing the problem? You can listen to the sound coming in through the USB from the Okto on the PC, you can listen to the sound before being sent out after the processing. That should suggest where the problem might be.

Also, any reason why the Nvidia shield isn't directly connected to the PC in another USB port and after processing play through the USB port connected to the Okto in USB audio interface mode? Avoids the $300 dongle.

 

[DaaDaa]

i cant seem to get it to work on moode. i have set i2s to none but i dont see where to set the dac8 as the output device. am I on the right track?

 

[Skookum]

Hi All,

Total ASR Noob here, this is my first post actually.

I've been visiting ASR for a while now and firmly believe in removing emotion and subjectivity from audio equipment measurement. As a result I ordered an Okto Dac8 Stereo yesterday. It will replace a Cambridge Audio CXN v2 (which i really enjoy and surely will miss).

My use case for the Dac8 will mainly involve streaming music over my LAN. I have seen that there is a long lead time, so i will buckle down and prepare for the wait. Keen to hear how those who have taken delivery are finding living with their Okto's?

 

[Colonel Bogey]

Unquestionably. No consumer DSP can run DSD.

What about either the RME ADI-2 DAC or the PRO?

 

[EchoChamber]

Hi All,

Total ASR Noob here, this is my first post actually.

I've been visiting ASR for a while now and firmly believe in removing emotion and subjectivity from audio equipment measurement. As a result I ordered an Okto Dac8 Stereo yesterday. It will replace a Cambridge Audio CXN v2 (which i really enjoy and surely will miss).

My use case for the Dac8 will mainly involve streaming music over my LAN. I have seen that there is a long lead time, so i will buckle down and prepare for the wait. Keen to hear how those who have taken delivery are finding living with their Okto's?

Welcome to ASR!!

After two weeks of usage, I have 0 complains. The sonic presentation overall is neutral and transparent - music just flows through it. Usage is very simple with the Apple remote and the large volume display makes it easy to read the attenuation value from the couch. I also find it to look slick in silver. It’s the only piece of gear I have exposed in my living room outside of my TV and speakers.

I think the most demanding part of it is setting up the Pi if you don’t intend to use Volumio like in my case. But that was a set and forget.

I currently use AES/EBU, Toslink and “Stream” through the Pi as inputs.