Is there any multichannel DAC easy to DIY in 2023?

[MCH]

Hello team,
I don't have any formal education in electronics but I have tried and finished a few simple electronic DIY projects in the last year and a half, related with audio or not. Quite often with the help of this forum. I enjoyed all of them and learned a lot.
Until now, my self imposed restrictions were 5VDC max, and when it comes to audio, stick to the digital domain. I feel like exploring outside of that if i find a feasible (for me) project.

My requirements are:

- 1 single DAC IC
- Multichannel. Minimum 4 channels, ideally 8.
- i2s inputs
- Balanced outputs.
- 24bit/96kHz
- Full reference schematics available, either from the supplier or from service manuals or projects available in the internet.
- Ideally 5VDC powered (like the topping D10) otherwise max 12VDC. (doesn't really matter to me if the balanced outputs are limited to a relatively low voltage, i would be more than happy with 3-4V)
- Chances to clear, at least on paper, say 96 db SNR. The higher the better, of course.
- I would consider hardware mode or having to program the chip if the required information is available, but hardware mode is of course preferred.
- Obtainable parts.
- Keep the exotic parts and snake oil to the minimum possible.

What are NOT my requirements:

- I don't aim for a soccer panther
- I don't need any USB interface, i2s input is enough
- I don't want premade PCBs or modules, commercial or diy, but the schematics are welcome.
- Volume control.
- Any status output.

I don't know where to start to search, and this is why i am asking here. But of course I have been exploring a bit and came across, for instance, the ES9017, that sells for 5 euros, ticks all the boxes and has hardware modes. But the recommended output stage in the datasheet works with opa1602 at 35Volts...(edit: I was mistaken, looking at pictures of the evaluation board it seems to work at 15VDC). Maybe i am too naive and any balanced output circuit will need such voltages. In this case i will just forget about it.

Thanks for any directions, indications, tips, whatever!

 

[Sokel]

8 Channels 384kHz 32bit ES9028PRO PCM DXD DSD Audio DAC

4 layer PCB, two solid middle ground plane NDK NZ2520SD 80Mhz low phase noise oscillator USB Type-C socket, Gold plated RCA socket Three ultralow noise 1.2V linear regulator Free 0.96 OLED display until stock last

www.diyinhk.com

8 Channels 384kHz 32bit ES9038PRO PCM DXD DSD Audio DAC

4 layer PCB, two solid middle ground plane NDK NZ2520SD 80Mhz low phase noise oscillator USB Type-C socket, Gold plated RCA socket Three ultralow noise 1.2V linear regulator Free 0.96 OLED display until stock last

www.diyinhk.com

 

[MCH]

8 Channels 384kHz 32bit ES9028PRO PCM DXD DSD Audio DAC

4 layer PCB, two solid middle ground plane NDK NZ2520SD 80Mhz low phase noise oscillator USB Type-C socket, Gold plated RCA socket Three ultralow noise 1.2V linear regulator Free 0.96 OLED display until stock last

www.diyinhk.com

8 Channels 384kHz 32bit ES9038PRO PCM DXD DSD Audio DAC

4 layer PCB, two solid middle ground plane NDK NZ2520SD 80Mhz low phase noise oscillator USB Type-C socket, Gold plated RCA socket Three ultralow noise 1.2V linear regulator Free 0.96 OLED display until stock last

www.diyinhk.com

thanks Sokel.
Do you know if the schematic is available? i don't manage to find it, it looks like they just sell the PCBs

 

[Sokel]

thanks Sokel.
Do you know if the schematic is available? i don't manage to find it, it looks like they just sell the PCBs

Probably not.
But I think there is documentation around if you search a little.

 

[MCH]

ah ok, i see. Buying a PCB is not what i want, actually, to just solder the components is the part of the project that i like the less. But thank you!

 

[Sokel]

ah ok, i see. Buying a PCB is not what i want, actually, to just solder the components is the part of the project that i like the less. But thank you!

Oh,ok.
As I looked closer to pic the small smd are already soldered,only caps,etc come unsoldered with it.
I would email him though,maybe there's options for you.

 

[mdsimon2]

I believe ESS offers schematics for their evaluation boards, although I don't see them provided on the ESS website, Mouser or Ismosys currently. Attached is the schematic for the ES9038 pro evaluation board. Maybe worth sending them an e-mail and see if they will provide you with a schematic for your desired DAC chip, although they are notoriously unhelpful to hobbyists.

Good luck!

Michael

 

[MCH]

I believe ESS offers schematics for their evaluation boards, although I don't see them provided on the ESS website, Mouser or Ismosys currently. Attached is the schematic for the ES9038 pro evaluation board. Maybe worth sending them an e-mail and see if they will provide you with a schematic for your desired DAC chip, although they are notoriously unhelpful to hobbyists.

Good luck!

Michael

Thank you Michael, this is exactly what i was looking for. A lot of good information there, most specially on the regulators and analog outputs.

I think i would be more interested in their ES9017/ES9027PRO for the following reasons:
1. Hardware mode available
2. cost. The ES9038PRO would cost me like 90 euros......
3. Can do my experiments with the super cheap ES9017, i can afford burning a couple of them, and when i feel i have something that works and want to achieve better performance, i could switch to the ES9027PRO, that is pin compatible and as of today can be had for less than 40 euros...

Yes, i saw the page where they show the evaluation boards but there is only a very brief description and a very small picture, that is all. I will try to contact them and see what happens. The problem is that these chips are very recent, and the chances to find the schematics out in the wild i guess are very small...

Another option is the AK4458, but only software mode, and the schematic for the evaluation board, that is available directly from their website, is for unbalanced outputs. Same thing for the schematic in the Denon AVR-X2500H service manual....

 

[MCH]

In between the different datasheets, the schematic of the 9038pro Michael posted and the few pictures of the eval boards, I think there is information enough to build something similar to the eval board of the es9017 without the USB interface (working in hardware mode).

I calculated ca. 50 euros in parts without the 6-15V power supply, almost half of it the 8 opa1602 op amps.

I might give it a try one day....

 

[somebodyelse]

I might give it a try one day....

If you could follow the FreeDSP header layouts for the connections you might find some other takers. I was going to suggest looking at the AnalogIO-x8 and populating only the output side, but you said you weren't interested in bare boards.

 

[MCH]

If you could follow the FreeDSP header layouts for the connections you might find some other takers. I was going to suggest looking at the AnalogIO-x8 and populating only the output side, but you said you weren't interested in bare boards.

ohh very interesting, thanks! with the AK4458, i knew there must be something out there with this chip.
Yes, i am not interested in replicating the PBC, but can use the schematic to build my own.
Thanks a lot, i will study it with attention.

 

[MCH]

Another candidate, that I believe could be the most versatile one for a 4/6 channel system:

ES9080 :
8 single ended channels. Comes with integrated line drivers, that is, outputs 2Vrms without the need for external op amps. That reduces the overall cost significantly!

Also comes with two spdif outs that output the two pairs of channels of your choice. This can always come handy for instance for active speakers with digital inputs.

Can invert the signal for each channel independently. I understand that this would allow to sum pairs of single ended channels into differential channels. In fact, they mention this possibility in the datasheet, but without discussing it too much.

All this would allow me to sum 4 single ended channels into 2 balanced for my main amplifier, that is balanced, use two single ended for my two single ended subs and still have 2 single ended channels in reserve.

I understand that I would need one additional op amp per each pair of channels that I want to sum up, but I cannot find any schematic anywhere. I did find a ESS application note that explains how to do the opposite (differential to single ended) but not the other way around. Anyone knows where I can find this information?

 

[somebodyelse]

I'm not sure what the additional opamps are for, but I may be misunderstanding. For the balanced channels you are sending the same data to say channels 1 and 2, but with 2 set to invert. The output of 1 goes to hot, and 2 to cold giving a balanced output. Did I miss something?

 

[MCH]

I'm not sure what the additional opamps are for, but I may be misunderstanding. For the balanced channels you are sending the same data to say channels 1 and 2, but with 2 set to invert. The output of 1 goes to hot, and 2 to cold giving a balanced output. Did I miss something?

You might be perfectly right, and if this is the case, that is great news.

(I probably got confused reading about transforming differential to single ended)

 

[MCH]

I am almost done with the schematics of what is intended to be a 2 balanced/4 unbalanced / 4 spdif channels DAC based on ES9080. Actually, the current datasheet is very good and contains almost all the information needed + it even gives examples of the code sequences to program the DAC for the most common use cases.
What it doesn't cover at all is the differential output setup, it just mentions "Differential mode pairs are Channels 1&2, 3&4, 5&6, 7&8". Fair enough.

Now i am a bit lost on how to get the channels that i need inverted to get the balanced outputs. I would appreciate if someone can help me understand what registers i need to change...

In principle, it seems clear to me that register 107 is the one i need to change. However the language has me a bit confused:

"NSMOD" seems to be "Noise Shaped MODulators" that appear indeed at the end of the digital signal path:

Register 1 takes care of activating the NSMOD clock and the DACs by pairs of channels (1&2, 3&4, ...), and it needs to be activated during the setup sequence. All good here.

But what gets me lost is register 107, that allows to "invert dither into each channel NSMOD" -what i dont understand- and, to add to my confusion, the default status is to invert one of the channels of each pair leaving the other not inverted for standard 8 channel unbalanced operation.

an example at the end of the datasheet suggest to change this register to set the pairs inverted or non inverted (that is 11001100) if you intend to sum channels (for better performance 4 or 2 single ended channels, as i understand it):

what do you guys think i should do to group i.e. channels 1&2 and 7&8 as two balanced channels? should i invert dither in 1 but not in 2, or in both, or in none, or is this irrelevant and i can leave it as default?
Additionally and much more important: i can always "try and see what works". The only way i have of doing it is to plug to an amplifier. Am i risking damaging the amplifier if i send a signal with the wrong phases??

Other than this, the project seems easy enough, i dont want to have to abandon for this alone, i would appreciate your input, thanks!

 

[MCH]

I already have most of the parts I need and the schematic ready to assemble a low cost ES9080 multichannel dac (no opamps needed, but max. 4 channel balanced and no hardware mode). However I cannot get rid of the idea of assembling as well a ES9017 based DAC, that provides 8 channel balanced and does have hardware mode.

With ES9017, most of the BOM budget goes to the 8 OPA1602 suggested in the TDS, and I want to understand if this is necessary.*

It is difficult for someone with no knowledge like me to find information about performance of opamps between the millions of subjective (to use a mild word) posts in audio forums, the only information I found close to my intended application is this old technical note from ESS themselves:

The document is old and based on a particular eval board and does not include OPA1602. And what is telling to my untrained eyes is that the difference in noise level can be significant if one considers the 12 euros a pop AD797, but otherwise the <1 eur NE5534 does a pretty good job…

Now the question is, can I extrapolate these results with a certain degree of confidence to NE5534 vs OPA1602 with a DAC (ES9017) specified at 120db DNR with OPA1602 and hope for a pretty close result?

Comments welcome.

*(Note: please note that all this is not to save 20 euros. I don’t need these dacs, I do all this as a challenge to see how low cost a multichannel DIY dac with a decent performance for my use case can go vs the current commercial offers)

 

[mumford]

My experiences with these OP amps is that one may not be able to tell any differences. A lot depends on the rest of your audio chain. Furthermore, the quality of your power supply matters more. Something that I wanted to try but never got around is a parallel nec 5532 amp, designed by Douglas Shelf, published in magazine. You can stack some of them and provide +20dBu out for your DAC.

 

[MCH]

Thanks @mumford yes, I don't expect relevant differences either, just want to make sure I keep the noise and the BOM cost under control

 

[mdsimon2]

I already have most of the parts I need and the schematic ready to assemble a low cost ES9080 multichannel dac (no opamps needed, but max. 4 channel balanced and no hardware mode). However I cannot get rid of the idea of assembling as well a ES9017 based DAC, that provides 8 channel balanced and does have hardware mode.

With ES9017, most of the BOM budget goes to the 8 OPA1602 suggested in the TDS, and I want to understand if this is necessary.*

It is difficult for someone with no knowledge like me to find information about performance of opamps between the millions of subjective (to use a mild word) posts in audio forums, the only information I found close to my intended application is this old technical note from ESS themselves:

View attachment 304858

The document is old and based on a particular eval board and does not include OPA1602. And what is telling to my untrained eyes is that the difference in noise level can be significant if one considers the 12 euros a pop AD797, but otherwise the <1 eur NE5534 does a pretty good job…

Now the question is, can I extrapolate these results with a certain degree of confidence to NE5534 vs OPA1602 with a DAC (ES9017) specified at 120db DNR with OPA1602 and hope for a pretty close result?

Comments welcome.

*(Note: please note that all this is not to save 20 euros. I don’t need these dacs, I do all this as a challenge to see how low cost a multichannel DIY dac with a decent performance for my use case can go vs the current commercial offers)

You might have better luck on DIYaudio as there are plenty of people that have DIYed DACs there.

I did some op amp swapping with the DIYINHK boards with an Ian Canada IV board and saw some improvement depending on op amps used. With the stock NJM2114D I got -105 dB THD+N and with the OPA1612 I got -115 dB THD+N. The primary difference was THD not noise, the NJM2114D was at about -112 dB N and the OPA1612 was at about -116 dB N.

I would love for you to make an ES9017 board if only because I want to try it out myself .

Michael

 

[MCH]

I did some op amp swapping with the DIYINHK boards with an Ian Canada IV board and saw some improvement depending on op amps used. With the stock NJM2114D I got -105 dB THD+N and with the OPA1612 I got -115 dB THD+N. The primary difference was THD not noise, the NJM2114D was at about -112 dB N and the OPA1612 was at about -116 dB N.

Oh wow that is an improvement.... don't make me fall down the rabbit hole.... 7.19x8... no that won't happen!
But your results are very different to ESS claims, i was assuming almost no difference in terms of distorsion. well, i see that each case is different, and i guess this answers my original question, thanks for that.

I would love for you to make an ES9017 board if only because I want to try it out myself .

I am afraid i will end up doing both. But first i need to figure out the digital part: all this depends on the success of another project that i am doing, so it might take some time. But it is true that ES9017 is indeed the DAC to diy, it even comes in qpf package, the 9080 doesn't.

You might have better luck on DIYaudio as there are plenty of people that have DIYed DACs there.

I have mixed feelings with DIYaudio + I am on a mission to bring more DIY to ASR outside the speaker world! A very unsuccessful mission so far i need to say... :-/