• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Okto 8 Owner’s Thread

phoenixdogfan

Major Contributor
Joined
Nov 6, 2018
Messages
1,153
Likes
1,024
Do not know anything about custom voltage other than the website saying you can get custom voltages from 1V to 12V.

Not sure why you would want an output voltage above 12V as I imagine all that would do is force you to lower the volume (and reduce SINAD as a result). I am not super familiar with Purifi but I assume your plan is to bypass the pre-gain so you only have a gain of 13 dB in the amp? Seems to me like 12V would be plenty in this case as you would still be able to drive the amplifier to full power. That being said not sure how often you change gear but having a 12V output voltage is excessive for most typical power amplifiers with 25-30 dB voltage gain.

In terms of fulfillment time I ordered a DAC8 Pro in the beginning of September and have not received it (~18 weeks to date). I am told it should be completed soon.

Michael
I also use Dirac Live which can necessitate lowering digital gain by as much as 10db.
 

mdsimon2

Active Member
Joined
Oct 20, 2020
Messages
152
Likes
143
Location
Detroit, MI
I also use Dirac Live which can necessitate lowering digital gain by as much as 10db.
The reason you may need to lower the gain with Dirac Live is that it can boost up to 10 dB, however the whole point of this is to make sure that your output will not exceed 0 dB. Assuming that you have Dirac Live implemented upstream of your DAC you will still be able to get 12V out of your DAC even if you cut the level in Dirac (preferably by exactly the amount of boost that Dirac has applied, so not necessarily 10 dB) but it will only occur at the frequencies you have boosted.

Which product are you using that has Dirac?

Michael
 

waynel

Addicted to Fun and Learning
Forum Donor
Joined
Nov 14, 2019
Messages
716
Likes
826
I also use Dirac Live which can necessitate lowering digital gain by as much as 10db.
I agree with mdsimon2, you are making a mistake with the gain structure here. There is no reason to have the DAC8 FS output greater than the sensitivity of your amp regardless of Dirac.
 

phoenixdogfan

Major Contributor
Joined
Nov 6, 2018
Messages
1,153
Likes
1,024
The reason you may need to lower the gain with Dirac Live is that it can boost up to 10 dB, however the whole point of this is to make sure that your output will not exceed 0 dB. Assuming that you have Dirac Live implemented upstream of your DAC you will still be able to get 12V out of your DAC even if you cut the level in Dirac (preferably by exactly the amount of boost that Dirac has applied, so not necessarily 10 dB) but it will only occur at the frequencies you have boosted.

Which product are you using that has Dirac?

Michael
It runs off my PC.
 

phoenixdogfan

Major Contributor
Joined
Nov 6, 2018
Messages
1,153
Likes
1,024
Ha. My A16 was 210 weeks and a day.
I bought mine new last January. It kept locking up so, I sent it back January 28th, and did not receive it back until after labor day. Had to send it back a second time and it came back within a month. Now I'm getting ready to do my first 24 channel PRIR using my LS 50s+ SB2000.
 

phoenixdogfan

Major Contributor
Joined
Nov 6, 2018
Messages
1,153
Likes
1,024
For me, it was apparently exactly 19 weeks - but the courier didn't ring the doorbell but instead dropped the package off at a store down the hill, and I'll have to pick it up tomorrow.
What air freight company did that? Did you instruct them to use that as a drop off? How did they know it would get to you? WTF!
 

mdsimon2

Active Member
Joined
Oct 20, 2020
Messages
152
Likes
143
Location
Detroit, MI
Do you use the PC as volume control? If so I wouldn't worry about Dirac boost at all.

If you are doing downstream volume control I would measure the actual Dirac boost you have applied with your PC using a loopback in REW and adjust the input level down by the boost amount. I am not currently using Dirac but when I was I measured an actual boost of less than 5 dB so a 10 dB cut is likely excessive.

Michael
 

phoenixdogfan

Major Contributor
Joined
Nov 6, 2018
Messages
1,153
Likes
1,024
Do you use the PC as volume control? If so I wouldn't worry about Dirac boost at all.

If you are doing downstream volume control I would measure the actual Dirac boost you have applied with your PC using a loopback in REW and adjust the input level down by the boost amount. I am not currently using Dirac but when I was I measured an actual boost of less than 5 dB so a 10 dB cut is likely excessive.

Michael
Since I go through JRiver (Dirac 3 is a vst plug-in) it is feasible to use JRemote (which I do have operational), and it is a 64 bit volume control. But I will probably just set JRiver for zero gain, use the volume gain on the JRiver plug in to set it so it won't clip). I don't think I will need to use all 10 db of gain reduction, b/c I doubt I'll have anything close to a 10 db correctio with any of the speakers I currently use or are contemplating using. But I will need to set the voltage to at least 10 Vrms, b/c I plan to run the Purifi with the input buffer bypassed.
 
Joined
Sep 13, 2020
Messages
74
Likes
45
Hello guys, I don't know if it has been asked already: what are you using to connect toslink outputs? Is there something cheap with multiple toslink -> aes converters?
 
Joined
Feb 13, 2020
Messages
47
Likes
29
The cheap option would be to combine a few consumer TOSLink/S/PDIF converters with e.g. Canare BPJ-XP-TR[ABC]. You can skip the BPJs for short cable runs, like 1 or 2m. Personally, I've considered buying a second hand Z Systems detangler, e.g. the Z-8.8, those are/were available with arbitrary combinations of in/outputs. http://www.z-sys.com/pp_routing.html
 
Joined
Sep 13, 2020
Messages
74
Likes
45
The cheap option would be to combine a few consumer TOSLink/S/PDIF converters with e.g. Canare BPJ-XP-TR[ABC]. You can skip the BPJs for short cable runs, like 1 or 2m. Personally, I've considered buying a second hand Z Systems detangler, e.g. the Z-8.8, those are/were available with arbitrary combinations of in/outputs. http://www.z-sys.com/pp_routing.html
The detangler is a nice solution but the additional price to pay is a little steep. The consumer converters you mentioned can keep a digital stream of multichannel audio intact?
 

Olli

Senior Member
Forum Donor
Joined
Mar 6, 2018
Messages
306
Likes
202
Hello Vasr,

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

In Hi-Fi level sound quality scene, you need to be very careful to avoid any degradation in speaker level.

Recently, I also intensively tried and experienced this kind of switching/distribution in speaker level signals in my multichannel project where I need to switch "single-amp system" and "multi-amp system" with one common speaker system.

After my intensive try-and-error on this issue, my current "physical" solution is a very primitive "SP Cabling Board";
View attachment 75324

As wrote in the above image, I once tested "Multiple-Terminal Electromagnetic Switching Relay" with remote controller and also "Multi-Terminal Snap-Toggle Switch" to switch the SP cabling connections. Both of them worked physically and functionally perfect; I found, however, audible slight degradation in sound quality was caused by these "Relay" and "Toggle Switch".

Then, I finally reached my definitive conclusion that the "physical screw-up of the cables" on terminal block is the best solution with completely no degradation of the signals in Hi-Fi system.

After reaching this conclusion, I searched and investigated a lot about the reasons for the degradation of the signals by those electromagnetic relays and toggle switches, and I found that these relays and switches have rather strong eletromagnets and/or permanent magnets in it, even toggle switches have tiny permanent magnet to "divert" possible ark spark from the contact metal plates, and these tiny but strong magnets are mal-affecting if the SP level audio signals would be switched by them.

I believe you may have, more or less, this kind of magnetic mal-affection on your SP level signals even using any of "consumer or professional audio switching gears" for SP level signals.

I am sorry that at present I cannot suggest best solution for your demands, but in Hi-Fi level audio, the switching of SP level signal should be handled very carefully, otherwise you would have audible degradation of the signal.

My present suggestion is that you should avoid any switching in SP level signals in your system, and you would be better to re-consider to have digital switching mechanism before the signals go into the DACs.

I found (and Pavel of OCTO confirmed) that you can achieve two DAC8PROs in sync manner by connecting first DAC8PRO's AES/EBU digital OUT (CH1+CH2) into second DAC8PRO's AES/EBU digital IN, and both DACs still can work as 8 channel USB DAC, and you would have 16 channel DAC port available for flexible output routing for 16 channel amplifiers. I assume this 16 channel DAC operation could be another possible solution for you.
@dualazmak, interesting. Are the 2 combined Oktos seen as one 16 CH soundcard in Windows when connected via USB?
 
Joined
Feb 13, 2020
Messages
47
Likes
29
The detangler is a nice solution but the additional price to pay is a little steep. The consumer converters you mentioned can keep a digital stream of multichannel audio intact?
The cheap devices that just have TOSLink in and S/PDIF out and no analog or HDMI in- or output are unlikely to mess with the data, I'd assume they just copy bit for bit from in to out. "Multichannel" with respect to the DAC8 will always mean 2 channel PCM or DSD on each AES/EBU input, i.e. no Dolby or DTS, so assuming you're talking about potential issues with multiple consumer grade converters connected to the inputs of the DAC8: I wouldn't anticipate any issues there either, since there should be little if any variation between them. I don't know about the sample rates that are supported by any of these devices, including the various models of the Detangler.

The going price for a ZSys 8.8 seems to be about $200. If you don't need any switching, that's obviously a steep increase over 4 converter boxes for $15 each. This one might be pretty close to what you want, you would just have to haggle over the price: https://www.ebay.com/itm/324265780669
 
Joined
Sep 13, 2020
Messages
74
Likes
45
The cheap devices that just have TOSLink in and S/PDIF out and no analog or HDMI in- or output are unlikely to mess with the data, I'd assume they just copy bit for bit from in to out. "Multichannel" with respect to the DAC8 will always mean 2 channel PCM or DSD on each AES/EBU input, i.e. no Dolby or DTS, so assuming you're talking about potential issues with multiple consumer grade converters connected to the inputs of the DAC8: I wouldn't anticipate any issues there either, since there should be little if any variation between them. I don't know about the sample rates that are supported by any of these devices, including the various models of the Detangler.

The going price for a ZSys 8.8 seems to be about $200. If you don't need any switching, that's obviously a steep increase over 4 converter boxes for $15 each. This one might be pretty close to what you want, you would just have to haggle over the price: https://www.ebay.com/itm/324265780669
Oh I see. Actually my idea was to downmix 5.1/7.1 coming from TV to stereo, in addition to my main setup. Looks like it can't be done so easily on a single input. Did somebody try to do something similar?
 
Joined
Feb 13, 2020
Messages
47
Likes
29
Oh I see. Actually my idea was to downmix 5.1/7.1 coming from TV to stereo, in addition to my main setup. Looks like it can't be done so easily on a single input. Did somebody try to do something similar?
And I assumed you had a device that had multiple TOSLink outputs for e.g. 7.1. You TV should be perfectly capable of downmixing anything it can reproduce to 2 Channel PCM on a single TOSLink output, there should be an option somewhere in the setup menus to switch between "bitstream" (or similar) and PCM.
 

dualazmak

Addicted to Fun and Learning
Joined
Feb 29, 2020
Messages
602
Likes
510
Location
Ichihara City, Chiba Prefecture, Japan
@dualazmak, interesting. Are the 2 combined Oktos seen as one 16 CH soundcard in Windows when connected via USB?
Please refer to OKTO Pavel's info at here.

In this case of dual DAC8PRO, the first (master) DAC8PRO should be in "PureUSB Mode", and the second (slave) DAQC8PRO should be in "USB/AES Mode". The AES/EBU digital connection using single XLR-type digital cable from first DAC8PRO into second DAC8PRO is the through digital output of CH1+CH2 for just "synchronization" of the two DAC8PROs. The second DAC8PRO, therefore, now would work as 6-channel USB DAC, which means that they can be used as total 14 CH synchronized USB DACs in Windows.

Please note that, since one DAC8PRO is just enough in my project, I never tried this dual DAC8PRO operation by myself, but Pavel of OKTO kindly confirmed it should work as described above.

BTW, I have actually confirmed and using AES/EBU sync CH1+CH2 connection from my DAC8PRO into another DAC, ONKYO DAC-1000 as shared here.
 
Joined
Sep 13, 2020
Messages
74
Likes
45
And I assumed you had a device that had multiple TOSLink outputs for e.g. 7.1. You TV should be perfectly capable of downmixing anything it can reproduce to 2 Channel PCM on a single TOSLink output, there should be an option somewhere in the setup menus to switch between "bitstream" (or similar) and PCM.
Yeah the option is there but I like to have control of the downmix, to avoid muffled voices and bloated bass in some movies. On my PC I downmix with a VST plugin and then there's Dirac processing on stereo.

Anyway, thanks for the feedback. I'll keep looking for some alternatives.
 

Similar threads

Top Bottom