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Raspberry Pi Klein combo interest

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If the Klein DAC 2 can do DSD, why can't this one do it?

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The idea is awesome, it's been floating in my head for a few weeks now too.

 

Complications I saw (for me) on the way, the driver(s) installed on RuneAudio (or the OSS of your choice) may or may not be compatible with the I2S DAC. As far as I know, all (most) official distributions have the HIFIBerry Dac+ drivers. They include the PCM interface (Clk Slave / FS / Data) plus the control interface (volume, sampling frequency, etc, etc). If you wanted to use your own DAC, you might have to rewrite the drivers (I'm still struggling with that).

 

Would the Klein v3.14159 still have coax and optical input? That's another thing that's putting me a bit off with DIYing that solution, I'd still want all three (PC/Coax/Optical) interfaces, seeing how I use them all.

 

I like the idea, but user-friendliness should be granted for all the not-tech-savvy folk.

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Betocool - yes there are probably going to be plenty of issues sorting I2S DAC compatibility out for sure.

After a bit of researching tonight it looks like trying to extract DSD via the I2S port on the Pi is a no go too.

Anyway the main thing was to check general interest in the project & it appears there certainly is.

OK, I have a spare Pi 2B & standard Klein motherboard so I will actually build up a working prototype & then do some serious testing - hardware & software. Also I was thinking of dropping the optical/coax inputs but it might be good to get a vote on that later.

Thanks everyone for all the feedback & input.

Once I have a working unit & performed some testing I will post an update & some photos.

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Rastus thanks for your wealth of information & no you have not overdone it - keep it coming.

As the Pi has no MCK out I will have to add reclocking & may even add galvanic isolation on the I2S lines while I'm at it.

 

The whole concept is to keep the unit fairly basic but with top quality audio. Ethernet in - RCA audio out - balanced could be an option too.

 

OK. Nice. And nicer. Indeed, indeed.

 

The idea is awesome, it's been floating in my head for a few weeks now too.

 

If you wanted to use your own DAC, you might have to rewrite the drivers (I'm still struggling with that).

 

I like the idea, but user-friendliness should be granted for all the not-tech-savvy folk.

 

Indeed... awe-SOME! I may be... able to... get this... done, maybe (I sure would move hell and high water to try). I agree with this, wholeheartedly... but I think the option should be there in case a tech savvy folk wanted to.. do what a tech savvy folk does (without infringing upon a not-so-tech-savvy folk of course).... sort of please all the people all the time. Anyway, thus the need for access to the mini SD card.

 

Betocool - yes there are probably going to be plenty of issues sorting I2S DAC compatibility out for sure.

After a bit of researching tonight it looks like trying to extract DSD via the I2S port on the Pi is a no go too.

 

Anyway the main thing was to check general interest in the project & it appears there certainly is.

OK, I have a spare Pi 2B & standard Klein motherboard so I will actually build up a working prototype & then do some serious testing - hardware & software. Also I was thinking of dropping the optical/coax inputs but it might be good to get a vote on that later.

Once I have a working unit & performed some testing I will post an update & some photos.

 

Plenty maybe, but insurmountable? No? I hope not, for not's sake. No go? Does that mean no go? Not a goer? As in, no go what-so-ever-go? Is that because of the hardware side of things? Because surely the software can be adapted....

 

"FFmpeg decoder plugin"

"DSD Support enables and disables support for playing DSD Audio."

http://www.runeaudio.com/documentation/runeui/mpd/

"Bitperfect and gapless playback of common audio formats and support of native DSD playback with DSD-over-PCM."

http://www.runeaudio.com/

 

Maybe I'm off the mark on this, I'm no good with circuitry stuff... really bad, bad, bad. Anyway, 'general' interest you got.... and here I was going to post over in the "Digital, DACs & Computer Audio" section and mention this thread to garner up some more interest (support). I really don't think 'they' are all watching the "Gieseler Audio" section for their Digital, DAC and Computer Audio information (or developments like this). OK, so grim it seems... and yet promising all at the same time. A vote, yes. Working unit, testing, update and photos... OK, gotcha. So... I'll wait here OK. Already wrestled the woman to the ground, pinched her purse, took out $900 (just in case you go all 'tough' on me and want to haggle some).

 

PS: But seriously Clayton (and I do mean this), thank you very much for even considering this as a possibility. It is a great idea, and it has great potential, and it was great to give you some input/feedback (after all the input/feedback you know you have given me). Tah.

 

PSS: I could get a lot more interested parties over here to post, in the twinkle of an eye. :popcorn:

 

PSSS: From the RuneAudio forum...

"...the new image for RP2/3 can play native DSD to USB DACs. For this to work the MPD configuration has to be tweaked by hand. This will change soon with the next image. Native DSD does not work with all DACs see https://github.com/lintweaker/xmos-native-dsd"

Linux native DSD playback support

https://github.com/lintweaker/xmos-native-dsd

Edited by rastus

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Rastus - I really appreciate your support & enthusiasm for this - thanks.

Yes put that $900 in a coffee tin,stash it somewhere safe & away from the wife.

DSD via Pi's I2S ports, please do your own research but but from from what I found & only from about thirty minutes of on line looking seems to suggest it wasn't possible. Of course this could change at any moment especially with the massive Pi resource base. I'm definitely a hardware man with limited Linux skills so not much help in that area. DSD via USB + Pi is certainly do-able, it's the I2S side where the problem is. I think the Pink Faun I2S Bridge will not extract DSD either so there is obviously something tricky required on the software side. Chanh & Tasso have done a lot with the Arm core boards as streamers so maybe we should bounce it off them. The Beaglebone Black seems stronger in the I2S area so I might do some more R&D on that.

Anyway I'm very keen to get this happening so as soon as I have a live hardware model working I will do heaps of testing.

Edited by Gieseler Audio

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Clay, forgive me if somewhere I've missed you addressing this but if I were you I'd first be checking out the existing rpi i2s dac addon boards (like hifiberry dac+ pro). You need to very sure sure your dac once you work out the i2s difficulties will clearly outperform these readily available pi i2s boards (sub $100us). By incorporating a Pi in your product, you are also taking ownership of the software and user interface issues -- a not trivial task that does not seem well suited to your existing core skills. Given the very rapid development going on in this area perhaps you could consider focusing on best exploiting your core skills. For example, you could readily distinguish your DAC from the competition using your great power supply engineering skill by designing for (optionally) a 1 or 2 additional configurable power supply outlets user configurable for 5v, 7.5v, 9v up to 2.5 amps and now you've got a dac with built in audiophile quality power supply(ies) on tap for the user's renderer of choice, be it a pi, BBB, Odroid, Sonicorbiter/cubox, microRendu or a zillion other upstream options that are here and going to appear in the digital transport/endpoint space. Absolutely not wanting to rain on the parade because making this all easier for folks to get started with audiophile quality digital music is laudable. Just food for thought anyway because I think the one thing established in this volatile space is that quality power supply makes a massive difference be it i2s or usb sources. At least get chummy with someone with the all the computer/OS skills if you want to incorporate a renderer into your dac. Hope this helps & best of luck with your R&D Clay. Cheers, essem.

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Hi Essem,

Thank you very much for your input & you have certainly brought up some valid points.

However there are some critical areas where my implementation is very different from those add on boards.

1. They all use budget entry level DAC chips & AFAIK none use the AK4490EQ or Saber 9018 which are the two leading chips at the moment.

2. They have very feeble output stages with very little decoupling.

3. The onboard power supplies are very lightweight usually just taking power from a header pin from the Pi.

In contrast mine is the opposite in all three cases.

I certainly agree with you though in that after sales IT support could become quite challenging.

At this stage I really just want to get one up & running attached to a Klein & see how it sounds.

If I can get it close to the Amanero USB input in terms of sound I feel it would be worth pursuing.

I think the add on boards with digital out (eg Hiberry digi) would be good as that way you can use a good seperate DAC.

We actually have a programmer on the team so I can call on him if required.

Anyway thanks for your input - it all certainty helps.

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Reading both posts above with interest, it seems to me (after the research I also did for me) that the clue lies in the driver software, not so much the hardware. If you have a Linux Geek (no offense, I'm one with lesser powers) on the team, well, that should make things easier.

 

I know it's an un-elegant solution, but what about the internal USB connections RPi -> Amanero (no driver required) and then the DAC on top? Just a thought. That way you can still keep Optical and coax all the same at the switch of a button!

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I just realise we sound worse than a marketing department!

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Anyway I'm very keen to get this happening so as soon as I have a live hardware model working I will do heaps of testing.

 

Now I've been thinking (all day), not a mere contrivance.... and I got something to say...

First, the little chrome plated switch, keep it.... but maybe slip it onto the back of the unit. I know it would be getting busy back there, but even so. Or, if you replace it with one of them new fan-dangled-bling-type buttons, the depress type (depress in, depress out), then I'd really like a LED one, with like a Batman symbol on it... so when I 'depressed' it, I would see the Batman symbol splashed across my back wall. Love that I would. NoT!

What I do know is this... in regards to computing: for every hardware item there must be a corresponding software program... usually a 'driver' at least, and sometimes an interface to configure or use said hardware item. That's with computers, like the Pi or Beagle Black. Now with the Pi, that uses a "device tree overlay"... not helpful I know. But, as with all of computing... they require updating, and regularly (to the point that said hardware becomes obsolete, as does the software that drives it). As such, the Pi may not be the new kid on the block in a few months from now.... but, your DAC's and LPSU's will be used for some years to come (even in their original configuration and design). Computing is different, to be polite.

I did do some reading about the AK4490 DAC chip (link below)... from my understanding, RuneAudio uses PCM as the transport for DSD (DSD piggybacks PCM, or embeds itself), where "Just like the WM8741, the AK4490 supports “direct DSD†processing bypassing the volume control and delta-sigma modulator. And like the WM8741, there is no automatic switching between PCM and DSD." Whatever that means. Also, the AK4490EQ chip's "DSD Mode: DSD Direct and DSD to PCM". Again, whatever that means.

And this.... "I2S and DSD shared lines: In order to facilitate the playing of both PCM and DSD content, it is desirable to have the same lines transmit PCM and DSD data. We find that in the AK4490, the I2S and DSD signals are shared. Here is a post I write earlier concerning shared I2S/DSD signal lines: [https://hifiduino.wordpress.com/2012/11/22/pcm-i2s-and-dsd-on-the-same-wires/]"

And whatever this means... "Native DSD Support: According to AKM, the volume control module and the delta-sigma modulator can be bypassed for DSD resulting in “direct†DSD rendering. The AK4490 contains an integrated low-pass filter specifically for DSD data."

Ref: https://hifiduino.wordpress.com/2014/12/07/akm-verita-4490-dac/

I was going to suggest using the USB as transport to the Pi, rather than the I2C....

Anyway, @@essem did hit the nail on the head... in many areas. A very well thought out post.

Something else to consider (maybe).... remove the Pi from the equation. A Klein DAC + LPS, with a USB connection (on the front/back) as transport and power to an external Pi (or whatever the user wanted to add/use, BBB, etc). Removes the software support issue. Or, a Klein DAC + LPS with space available to add a Pi inside the unit case.... but I think this is not such a good suggestion.

This is less about the DAC chip being used, and more so about the software. I think.

 

By incorporating a Pi in your product, you are also taking ownership of the software and user interface issues....

 

....perhaps you could consider focusing on best exploiting your core skills. For example, you could readily distinguish your DAC from the competition using your great power supply engineering skill by designing for (optionally) a 1 or 2 additional configurable power supply outlets user configurable for 5v, 7.5v, 9v up to 2.5 amps and now you've got a dac with built in audiophile quality power supply(ies) on tap for the user's renderer of choice...

 

Brilliant @@essem....

 

1. They all use budget entry level DAC chips & AFAIK none use the AK4490EQ or Saber 9018 which are the two leading chips at the moment.

2. They have very feeble output stages with very little decoupling.

3. The onboard power supplies are very lightweight usually just taking power from a header pin from the Pi.

In contrast mine is the opposite in all three cases.

At this stage I really just want to get one up & running attached to a Klein & see how it sounds.

 

Yes.... indeed. Thus the reason I jumped on this a soon as your brought up the subject. Interesting it is. :thumb:

 

I really want you to get one up and running, too. Just to see how it sounds, too. :party

 

Edit: This is as close as I could find for the Sabre:

AUDIOPHONICS I-Sabre V3 DAC ES9023 TCXO Raspberry Pi 2/3 A+ B+ / I2S

http://www.audiophonics.fr/en/diy-dac/audiophonics-i-sabre-dac-es9023-v2-tcxo-raspberry-pi-20-a-b-i2s-p-10657.html

And a discussion about them on the Volumio forum...

Audiophonics I2S DAC's I-Sabre ES9023 (two types)

https://volumio.org/forum/audiophonics-i2s-dac-sabre-es9023-two-types-t3095.html

 

PS: No need for a response, I'm just throwing it out there.

Edited by rastus

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Guys,

for best performance I would connect the Sonore Microrendu to the Klein DAC II.

This combination should offer an unbeatable price/performance ratio and be much better than the Raspberry Pi.

Matt

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Or get one of these...

 

pi2design-503hta-dac-i2s-pour-raspberry-

 

Is this retrograde, or retro-active...

Edited by rastus

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OK, what about this.... the Rapsberry Pi can have many addon cards, most people use a Pi DAC (with RCA outputs), but there is another addon card, a Pi DIGI... this is used when one wants to output from the Pi to an external DAC (uses coax and optical connectors).

So we have.... Pi ---> I2C ---> DIGI ---> coax/optical ---> external DAC ---> etc

So my understanding is... the DIGI is a I2S interface for direct digital output from the Pi, uses PCM. Should be called a 'transport' or 'interface' card maybe, instead of a "Sound Card". But, couldn't those coax and digital connectors be removed from the DIGI and wires added to connect to the Klien DAC board, surely.

Or, instead of using DSD that the Klein DAC II uses, why not use the original Klein DAC (no DSD, only PCM?).

Also, if you connect the Pi to your Klien DAC via USB, the Pi (or whatever software your running on the Pi) should auto detect it... hopefully.

Anyway, heres the link to the DIGI...
http://www.geekroo.com.au/products/1664

 

PS: Just thinking out loud, that's all.

 

Edit-1: Plus, I've noticed that both the coax and optical connections output a signal at the same time, they can both be used together... could result in 4 channels, maybe.

 

Edit-2: "At this stage I really just want to get one up & running attached to a Klein & see how it sounds." <----- I supplied this information to maybe assist you to do this....

 

Edit-3: Ooops, just re-read the thread and seen you mention the DIGI boards, LoL!

Edited by rastus

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does AK4490EQ need MCK in it's I2S input because raspberry pi doesn't have MCK pin. you can connect raspberry pi to a dac through I2S as long as it can derive the MCK from LRCK rather needing a dedicated MCK signal

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AFAIK the AK4490 needs a seperate MCK input. The S/PDIF receiver (Wolfson WM8804) & Amanero Asynchronous USB board I use in my DAC both have MCK outputs which connect to the MCK input pin on the AK4490.

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Compute model actually makes things bigger when it's implemented. It's designed for multiple processor computing not for small size

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Hi Guys,

well a few months ago I built a new prototype streamer DAC combo based on a Raspberry Pi.

All AKM DAC's run in slave mode & so it is not possible to connect the Raspberry PI  directly into the DAC chip.

To get around this I used a device called the Kali reclocker.

https://allo.com/sparky/kali-reclocker.html

This reclocks all the I2S lines & included a high quality master clock output - perfect to drive the AK4495 DAC chip I used.

I tried quite a few distros on the Pi & settled on moOde audio as it sounded the best, easy install & excellent support.

I loved the sound quality but there were two issues.

An intermittent loud click on pause/track change & I was not totally wrapt in the simple web based remote system.

Tim from moOde audio was very helpful regarding the clicks but we never managed to solve the issue & put it down to the hardware.

I put it aside for a few months but I still had a  gut feeling that different software may solve the loud click issue.

I kept reading good things about Picoreplayer so today I gave that a shot.

Success!

It is considerably more involved in the setup but well worth the effort.

All clicks have virtually disappeared & the odd one that occur are so faint they are barley noticeably.

The other huge bonus is I can use iPeng to control it. This app is way more slick than any simple web base style of interface.

http://penguinlovesmusic.de/ipeng-8/

Any compatibility Logitech Squeezebox app will work so plenty of Android solutions as well.

 

My hardware setup.

I'm using the AK4495 in a relatively simple setup with a transformer output stage similar to the Groß DAC.

Nice low noise PSU's all round with a dedicated high current one for the Kali/Pi section.

Simple muting so no switch on/off pops.

Why did I pick the AK4495 - I particularly like the sound of it, easy to implement & reasonable cost.IMG_1228.thumb.JPG.c8e924c61fe90549752724718c0e37f4.JPG

At this stage I'm not quite sure on how I will market/price it. The SD card is hard to get to so I will probably need to run that to a external socket.

Anyway lots of possibilities & potential for sure!

I better get back to Groß DAC production for now or I will have unhappy customers.

Stay tuned!

 

 

    

 

 

 

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It gets better.

Just discovered iPeng's built in app for Tidalimage.png.1c6037ea131613fb25f208ff32f5642c.png

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5 hours ago, Gieseler Audio said:

...

I kept reading good things about Picoreplayer so today I gave that a shot.

Success!

It is considerably more involved in the setup but well worth the effort.

 

You might be interested to know that @Greg Erskine is one of the amazing devs of pCP ;)

The pCP team are super active and adding new features "a lot"

Did you try the "audio" version? And have you seen the experimental bluetooth support is being played with?

 

 

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Yes Greg seems a great guy & very regular with updates & info even here on SNA.

I did go for the “audio version” & it is sounding extreamly good.

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FWIW Clay  I am extremely interested in this!!!

 

I know you probably have a lot on your plate  ATM but if you can make this happen.......

 

This is a great idea for a product.   

Edited by Jeddie

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Well I’ve been running this for a couple of days now & it's rock solid - not one glitch or pop.

I’m controlling it with iPeng 9 running on a thirteen inch iPad Pro & have to say it is a lovely interface.

iPeng have just done another update which includes Roon playback support.

http://penguinlovesmusic.de/2017/07/13/summer-news-from-ipeng/

My streamer/DAC is running (balanced or RCA options) directly into  power amp & has plenty of drive level.

The AK4495 analogue section is runing on 7v so max output is up a bit at around 3v rms.

Softwareware volume control in iPeng - very solid & reliable.

Music sources I’ve been using;

Tidal (flac)

USB stick with hi Rez music files

Streaming radio - I’m amazed just how good this sounds too.

Artwork support is excellent & not one album cover missing in any of my music sources.

I’m getting very excited about this now as you may have noticed.

After two beers last night & looking across at my Hi-Fi rack I’m thinking - this little box can replace my Konverter + Auralic Aries combo & is about a quarter the cost. Sound quality is obviously down a bit but still extremely good.

I will probably do two versions of it.

An entry level one similar to photo above & a ultra version more like the Groß DAC.

Now there is just one limitation in that the Kali reclocker I use (& need) does not support DSD.

There are more complex & expensive reclockers out there that support DSD but I will need to do more R & D to see if any are suitable. 

Stay tuned!

 

 

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