Raspberry Pi Klein combo interest

[Gieseler Audio 1,927]

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.

[betocool 1,670]

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!

[betocool 1,670]

I just realise we sound worse than a marketing department!

[rastus 194]

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.

 

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

 

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 May 26, 2016 by rastus

[matth 125]

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

[rastus 194]

Or get one of these...

 

 

Is this retrograde, or retro-active...

Edited May 26, 2016 by rastus

[rastus 194]

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 May 27, 2016 by rastus

[mloutfie 715]

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

[Gieseler Audio 1,927]

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.

[huxmut 656]

Word of a new Compute Module based on the Pi3 are floating around. I wonder if that would be more suitable ?

http://hackaday.com/2016/07/15/the-raspberry-pi-3-compute-module-is-on-its-way/

 

[mloutfie 715]

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

[Gieseler Audio 1,927]

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.

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!

 

 

    

 

 

 

[Gieseler Audio 1,927]

It gets better.

Just discovered iPeng's built in app for Tidal

[huxmut 656]

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?

 

 

[Gieseler Audio 1,927]

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.

[Jeddie 199]

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 October 31, 2017 by Jeddie