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Need help using the I2S header in the miniDSP 2 x 4 HD to add 2 spidf digital outputs to unit.

phoenixdogfan

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Joined
Nov 6, 2018
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#1
The miniDSP 2 x 4 is an extremely versatile processor which can function as a 2 X 4 digital crossover, PEQ, FIR filter, and now can run a full version 2.0 of Dirac Live. It accepts USB input for both control and audio inputs (one of the few that does) as well as spidf coax, and 2-channel analog via RCA with A to D conversion. In short it's very close to an ideal digital processor.

The problem is it's also wedded to a quite mediocre DAC which Amir reviewed about two years back and comes with only analog out, which means it must be used with that DAC if it's used as configured straight out of the box.

All is not lost, however, since it has a header on its board for connection of digital output circuitry via I2S which would bypass the inboard DAC.

Someone in Reddit used those I2S outs to create spidf digital outputs with a similar unit called the miniDSP DDRC-24 which differs from my 2 X 4 HD only in a software module it comes equipped with.

I'm listing the thread to give a complete explanation of the project. What I want done differs from what he did in that I want 2 spidf outputs so the unit has digital outs for a four channels it outputs.

https://www.reddit.com/r/audiophile/comments/6jn711
That's the reddit thread. The manual for the unit shows the position of the header on the board of the unit and lists all the pin values. That information is listed on page 17 of the manual.

To be completely honest here, I really don't want to undertake this conversion myself. It's way beyond my pay grade. I can solder, assemble cabinets, but when it comes to attatching connections from a circuit board, possibly doing surface mount soldering, creating openings in an enclosure, and adding spidf sockets...let's just admit I'm unqualified for that kind of thing. I know my limitations.

So, what I would like is for someone to give me a phone number or an email of a qualified technician who I could pay to do this. Can anyone here hook me up?

If I could do this, I could use the crossover with my LS 50/SB2000 system and use the DL Live 2.0 on the minidsp and send the spidf digital output to an Octo Research 8 for 2.1 channel sound, and I could also send 5.1 channel straight out the my PC via USB for when I'm using the OCTO as a DAC for a 5.1 surround sound, and still have 2 XLR channels left on the OCTO to use as a DAC for my THX AAA 789 headphone amp.

In short I could I think optimize the electronics on my three use cases (2.1 stereo sound, 5.1 surround sound, and 2 channel headphone sound) with a minimum of boxes, connectors, adapters, and converters.

Any help will be greatly appreciated.





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LD_

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Feb 13, 2020
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#4
Wow, what a great project! Thank you for sharing.

The on-board DAC implementation by miniDSP indeed does not show the best performance on amirm's measurements but in an average 'real' listening environment, most probably none of those "flaws" would be audible - even less during music playback (due to auditory masking).

However, it would be very useful to do this modification - as you pointed out and for lowering [total] electronic noise - but I guess it should also be possible to add an AES3 output to the DDRC-24, which I would be more interested in, instead of S/PDIF.

Unfortunately, this likewise greatly surpasses my competencies but I certainly would appreciate updates on your progress with this modification. :)

Good luck!
 

phoenixdogfan

Active Member
Joined
Nov 6, 2018
Messages
201
Likes
210
#5
Wow, what a great project! Thank you for sharing.

The on-board DAC implementation by miniDSP indeed does not show the best performance on amirm's measurements but in an average 'real' listening environment, most probably none of those "flaws" would be audible - even less during music playback (due to auditory masking).

However, it would be very useful to do this modification - as you pointed out and for lowering [total] electronic noise - but I guess it should also be possible to add an AES3 output to the DDRC-24, which I would be more interested in, instead of S/PDIF.

Unfortunately, this likewise greatly surpasses my competencies but I certainly would appreciate updates on your progress with this modification. :)

Good luck!
If you know anyone with the technical skills who might be interested in doing this project for me, I would be interested in a phone number or an email. I'm in the US and I would pay well. And you're right, an AES/EBU (actually two) would be my preferred digital out.
 
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