Okto Research modules

[Franta]

Hello everyone,

It's our pleasure to present to you OKTO DAC8, a stereo AND 8-channel DAC in one module. Based on numerous prototypes, many hours of PCB design and a lot of testing with R&S UPV audio analyzer, DAC8 is made to excel as a part of multi-way or multi-channel audio chain, while being the ultimate stereo module as well.

All the features, measurements and documentation can be found on our website: Okto Research.

Key features:

• NEW - stereo mode with unique 4+4 I/V stages paralelling
• Up to 384kHz I2S, DSD256, DSD128 over PCM or 96kHz SPDIF input
• Ultra-clean output spectrum with measured 0.000063% (-124dB) THD and 132dB-A / 125dB-A dynamic range (stereo mode / 8-channel mode)
• Compatible with HiFiDUINO, USBstreamer, NanoSHARC and MiniSHARC and many other products
• 8 analog stages with fully differential OPA1632 op amps
• Access to ES9028PRO's 32-bit internal volume control with a potentiometer thanks to onboard MCU
• Headphone amplifier with OPA1622 opamp capable of delivering 100 mW into 32 ohm load with 0.00016% (-116dB) THD
• Highly optimized 4-layer PCB design with attention to RFI immunity
  

Typical applications:

• As a part of hardware-based digital crossover together with MiniSHARC, FreeDSP or any other DSP module with digital (I2S or DSD) output
• As a part of software-based digital crossover like 64-bit DSP engine in JRiver and any USB>I2S module like USBStreamer
• As a standalone 8-channel DAC for multichannel playback together with USBStreamer
• As a stanalone ultra-performance stereo DAC with any stereo USB>I2S interface or with SPDIF input

Available for 489 EUR at www.oktoresearch.com

Franta Blazek,
info@oktoresearch.com

 

[eugenius]

Can this work with the minidsp nanosharc kit to bring 8 channels with volume control?

miniDSP Kits : nanoSHARC kit

 

[Franta]

Hello eugenius,

Both NanoSHARC and MiniSHARC DSP modules are supported. In fact, most of DAC8 users are going to use one of those modules.

 

[wcwc]

I guess I am just a bit confused on the power requirements. Is it 2x 15VDC and 5 VDC or 2x +/- 15VDC and +/- 5VDC? On the board you call out + and - for each voltage.


What is the extra header for that is in picture, but not on the schematic representation?


Since the spdif and I2S share the same inlet pins, all input selection would need to be done external to the board. Do we need to let the DAC board controller know which data type we are sending the DAC?

 

[Franta]

Hi,

it is 2x separate 15VDC and 5 VDC. Our new OKTO PSU has all the required voltages.

The headers for 15V input and headphone output shown on photo are split version from first prototype board. Actual version of the board has connectors as shown in manual.

DAC chip can detect input data format, no external control is needed. S/PDIF is supported only in 2-Channel mode.

 

[MarkB1]

Looks like an excellent product that will make the most of the Nano/MiniSHARC modules.

Now all you need is a nice display & IR remote kit to complete the package 🙂

 

[diyaudnut]

Seems like a well integrated MC DAC. Any reason 9038 was not considered?

 

[Franta]

HYPERTUNE: Thank you. We are already working on our front-panel module with display and remote control.

diyaudnut: We certainly have plans with ES9038PRO too, it'll just need some more R&D to make sure OPA1632's can cope with increased amount of current without additional distortion and also to sort out cooling. However, 9028 is a great chip. Look at our measurements, sounds great too.

 

[GreatLaBroski]

I'm interested in this, looks nice. I'm curious if you're planning on adding more documentation to the website such as pin layout configurations and the like.

 

[Franta]

Hi GreatLaBroski,

you can find full documentation here.

 

[Franta]

Let me introduce you our new OKTO PSU.

• Designed for OKTO DAC8
• Separate galvanically isolated 5V voltage for any input/DSP module (like MiniSHARC by MiniDSP)
• Low radiation Talema transformers, Schottky rectifiers to avoid diode switching noise
• 10 000 µF of filtration capacitance for each voltage
• Selectable mains voltage 120 / 230 V
• Dimensions: 122.5 x 111 mm

Price 89 €

.

 

[diyaudnut]

Thanks Franta.
Will be looking for your 9038 based solution.

I understand it has its challenges. But there is a good implementation in Oppo UDP-205.

Also as someone pointed out, a display and control interface is important.
Can you check if this works with the nice controller than Iancanada developed?

 

[Franta]

We are working on our frontpanel control interface now.

Can you please send me link to Iancanada's module so I can check it? Thank you.

 

[Franta]

But basically, our OKTO DAC8 has ES9028PRO's I2C bus on a connector, so any driver with I2C compatible with ES9028PRO should be ale to control it.

For example, Hifiduino by Dimdim is compatible with OKTO DAC8.

 

[Stoff]

Looks great!! I am interested in the OKTO DAC8 for a high end HTPC. With the DIYINHK units, the digital volume (on dac) can follow the PC volume. This would mean that I would not need a vol pot/remote solution. Would this be possible?

 

[Franta]

Thanks! They list compatibility with CS4398, PCM1794 and ES9018S, but not ES9028PRO, so that would not work, because it has got different register configuration. However, it is ok to control volume in software as long as your player operate with 32 bit or more internally (as many do) and if you use ASIO/Wasapi.

 

[diyaudnut]

We are working on our frontpanel control interface now.

Can you please send me link to Iancanada's module so I can check it? Thank you.

Franta,

Take a look at this
ES9018K2M, ES9028Q2M, 9038Q2M DSD/I2S DAC HATs for Raspberry Pi

Please keep the thread updated on the 9038 version. I'm interested.

 

[Franta]

That's nice looking controller board, however, author only lists compatibilty with mobile series Sabre DACs, not PRO-series. As soon as they update it to support those, it should work with DAC8.

I will keep this page updated with progress with our modules, including the 9038 compatible board development.

 

[pos]

Hello Franta,

That looks like a fantastic solution.

You mention the USBstreamer in your initial post, do you have example on how to proceed, including cable harness and all?
Do you think it would also be compatible with the UDIO-8 (USBstreamer + in/out card with a specific firmware). IDeally I would want to keep the UDIO-8 AES inputs, but use the DAC8 for the outputs.

Is your DAC completely pop-free on turnon/turnoff a sampling freq change?

 

[Franta]

Hi pos, thank you!

You mention the USBstreamer in your initial post, do you have example on how to proceed, including cable harness and all?

We can provide you with appropriate cabling and connection drawing. Combination of USBStreamer and DAC8 works without any issues, we use it ourselves in our test device.

Do you think it would also be compatible with the UDIO-8 (USBstreamer + in/out card with a specific firmware). IDeally I would want to keep the UDIO-8 AES inputs, but use the DAC8 for the outputs.

If there is I2S (bit clock, frame clock, data1-4) available on some header in the UDIO-8 as is in case of the USBStreamer, then yes. However, DAC8 cannot operate in 8-channel mode with SPDIF/AES3 signal.

Is your DAC completely pop-free on turnon/turnoff a sampling freq change?

Yes, it is.