Something cool for Raspberry Pi/ODROID: I2S/DSD isolator HAT with native DSD decoder

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iancanada

iancanada

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Joined 2009
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Greg Stewart said:
Ian,

Very cool and I bet it sounds very good. Especially since you aren't using the Pi's 3.3v to power the HFBD+P's PCM5122 digital side & the board's clocks like the unt does stock.

I have a HFBD+P I've modified the heck out of... some details on what I did for a page or so before and after this post:

http://www.diyaudio.com/forums/digi...ry-dac-pro-hw-mods-anybody-3.html#post4626613

And some additional details and pix here:

http://www.diyaudio.com/forums/vend...-here-bal-bal-se-se-lpuhp-18.html#post4626581

With three good power supplies feeding the R-Pi and the HFBD+P's 5v and 3.3v separately, it was sounding very good. THEN I tried the modified HFBD+P on an Allo.com Kali reclocker board in slave mode (where it gets the clock from the input feed) instead of master mode (where it feeds the clock to the Pi... and of course along with adding a 4th supply) and have preferred it that way ever since.

BUT I just got the new Allo.com Boss DAC going last night... Like the HFBD+P, it also uses the PCM5122 chip in master mode with 2 clocks to send to the Pi for master clock duties. I hear it sounds good that way too, but based on my experience with the HFBD+P, I first tried the Boss on a Kali reclocker board and 3 good power supplies, again 1 feeding the Pi, 1 the Kali, and the 3rd the Boss.

It only took a couple of minutes to hear that it was handily beating my modified HFBD+P... and it should, using better regs and power filter, along with a more sophisticated power bypassing network AND better spec'd NDK clocks (same as what Allo.com uses on the Kali).

I know you are super-busy, but you should get one of these to try on your isolator board... consider it a HFBD+P with the upgrades as above for only 1/3 more ($60 USD vs $45 USD for the HFBD+P)... and while I plan to further upgrade my HFBD+P to try and equal the Boss, I find my will to do so very low as the Boss is that much better with almost no work in my part!

Then others have reported better sound out of the PCM5122 by upsampling/filtering to 384 which causes a bypass of the PCM5122's built-in filters. With an LMS-server/SqueezeLite setup, you can do this either on the Pi (ok) or the LMS server computer (better).

John Swenson (designer of the Bottlehead DAC that uses the PCM5142 along with the Sonore Rendu Signature and MicroRendu AND the Uptone Audio Regen, JS-2, LPS-1, and now their forthcoming IsoRegen) started this idea here:

Upsampling Impressions

and Soundcheck has found it sufficiently beneficial with both the HFBD+P & the Allo Boss to write a blog post on how to do it here:

Raspberry PI - I2S-HATs @ 384k

All of that is why I asked for the feature-set in my post above... the isolator to provide the benefits you're already hearing, the reclocker to get what I heard going to the Kali with my HFBD+P (though with the Boss it MAY work better in Master mod, again I'll try that at some point), and the FPGA upsampling to get the best out of those (and many other) DAC chips.

Be that as it may, I am VERY excitedly awaiting your isolator hat!!!!!

Greg in Mississippi

P.S. I forgot you can find more info on the Boss DAC here:

http://www.diyaudio.com/forums/vendors-bazaar/300689-master-dac-boss-rpi.html

and here:

http://www.diyaudio.com/forums/digital-line-level/304004-my-new-boss-another-pi-hat.html
Click to expand...

Thanks Greg for the very detailed information.

I went through your thread "Hifiberry DAC+ Pro - HW mods anybody?" time ago. That's why I'm very interested in IsolatorPi working with DACs in master clock mode. An isolator can make your DAC benefiting more from good power supply, as well as good low jitter local XOs.

My IsolatorPi will be capable for 768KHz, so should be no problem working with I2S upsampled to 384KHz. You will see the finial release version in a couple of weeks.

Regards,
Ian
 
G

Greg Stewart

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Joined 2003
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iancanada said:
Thanks Greg for the very detailed information.

I went through your thread "Hifiberry DAC+ Pro - HW mods anybody?" time ago. That's why I'm very interested in IsolatorPi working with DACs in master clock mode. An isolator can make your DAC benefiting more from good power supply, as well as good low jitter local XOs.

My IsolatorPi will be capable for 768KHz, so should be no problem working with I2S upsampled to 384KHz. You will see the finial release version in a couple of weeks.

Regards,
Ian
Click to expand...

Thanks for the additional update, Ian! Sounds very good! And the Boss should also benefit greatly from isolation from the R-Pi, whether in master or slave mode.

Again, I eagerly await the isolators!

Greg in Mississippi
 
B

Blitz

Member
Joined 2002
Hi Ian, couldyou considerthe beaglebone black into your concepts ? A much superior I2S quality than Pi...https://hifiduino.wordpress.com/2015/03/02/bbb-dac-developments/

...but ideally a solution, which is reusing your big fifo and MC modules...

Currently I run a Alix/Linux-->Waveio-->Ian's fifo-->Dual Mono BuffaloIII

It would be nice to avoid the UsB part and have a BBB/Botic-->Ian's Fifo, which would required a light veraion I guess of what Twisted pear has developed.
 
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iancanada

iancanada

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Blitz said:
Hi Ian, couldyou considerthe beaglebone black into your concepts ? A much superior I2S quality than Pi...https://hifiduino.wordpress.com/2015/03/02/bbb-dac-developments/

...but ideally a solution, which is reusing your big fifo and MC modules...

Currently I run a Alix/Linux-->Waveio-->Ian's fifo-->Dual Mono BuffaloIII

It would be nice to avoid the UsB part and have a BBB/Botic-->Ian's Fifo, which would required a light veraion I guess of what Twisted pear has developed.
Click to expand...

Hi Blitz,

I'm interested in that. But It would be another project because the connectors and signal positions are different.

Do you have any details about multi-channels application of BBB/Botic?

Regards,
Ian
 
T

trung224

Member
Joined 2016
Hi Ian,
I have small question about the RPi isolator. In my experience, powering Raspberry Pi via 5VGPIO, which bypass some noisy protection circuit in RPi, yields a better sound quality than powering RPi by mini USB. If I use your isolator, could I still have an option to powering RPi from GPIO pin?

Regards,
Trung
 
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T

trung224

Member
Joined 2016
Thanks Ian.
I'm looking forward to integrate your Rpi isolator to my diy streamer which contain Rpi3 and Pi2design 502DAC. My 502DAC has the 5V input option und jumper to disconnect 5V from RPi GPIO, but it doesn't isolate noisy ground from RPi. Your isolator will be a great solution for this problem.

Regards,
Trung
 
S

surfchampion

Member
Joined 2016
trung224 said:
Hi Ian,
I have small question about the RPi isolator. In my experience, powering Raspberry Pi via 5VGPIO, which bypass some noisy protection circuit in RPi, yields a better sound quality than powering RPi by mini USB. If I use your isolator, could I still have an option to powering RPi from GPIO pin?

Regards,
Trung
Click to expand...



Hi, Trung

From my opinion there are a better way to power RPi from totally independent PSU directly to exact points on RPi board.
The idea are goes around RPi's power chips and give output up to three positive voltages and change all the switching power supply sections of MODEL B + (5 V, 3.3 V, 1.8 V is independently fed)
865cd5764a21bd26522097c34d93bcd4.jpg


One of the good example is DC Power Unit for Raspberry Pi kit made by
http://www.easyaudiokit.com/bekkan/distr/distr.html

It's a monobloc with exact place for RPi board itself.
Look at this
2aa2d13bbe683761f3b8de22e1be479d.jpg




Отправлено с моего iPad используя Tapatalk
 
G

gwikse

Member
Joined 2010
surfchampion said:
Hi, Trung

From my opinion there are a better way to power RPi from totally independent PSU directly to exact points on RPi board.
The idea are goes around RPi's power chips and give output up to three positive voltages and change all the switching power supply sections of MODEL B + (5 V, 3.3 V, 1.8 V is independently fed)
865cd5764a21bd26522097c34d93bcd4.jpg


One of the good example is DC Power Unit for Raspberry Pi kit made by
http://www.easyaudiokit.com/bekkan/distr/distr.html

It's a monobloc with exact place for RPi board itself.
Look at this
2aa2d13bbe683761f3b8de22e1be479d.jpg




Отправлено с моего iPad используя Tapatalk
Click to expand...

That looks interesting.
 
S

surfchampion

Member
Joined 2016
Greg Stewart said:
@surfchampion... can you post a direct link to this item on their website. I had Google translate it an tried, but could not find it.



Quite interested... probably worth a separate thread, tho!



Greg in Mississippi
Click to expand...



Hi, Greg

Look at the end of this section
http://www.easyaudiokit.com/bekkan/Raspberry/Raspberry.html
And here:
http://www.easyaudiokit.com/bekkan/Raspberry/Raspberry2.html

Make your Chrome native language-->> English, install Google Translate Extension, that's it.

If you'll have any difficulties I can put all translated sections in Google Doc file and give you a link, if you wish.


Отправлено с моего iPad используя Tapatalk
 
G

Greg Stewart

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Joined 2003
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Thanks! I was getting good translations, but just couldn't find it... I see I did not look far enough down in this section.

Got it now!!!

I'm thinking of a separate thread as a collector thread for all the various R-Pi I2S DAC setups, optimizations, and mods... many of those apply to most or all, such as this (and the topic of this thread, Ian's Isolator board).

Thoughts on this?

Greg in Mississippi
 
G

gwikse

Member
Joined 2010
I am looking at the sketchup rpi isolator model again. Are there any changes that have been done on the actual board since I made the model ages ago so that it does not look right to you IAN?

https://3dwarehouse.sketchup.com/mo...DSD-Isolator-by-DIYaudio-member-IanCanada-WIP

As for other projects I wish was done by someone there is a clear no1; coax / optical input + wm8804 + i2s switch from RPI`s I2S lines (underneath) to the wm8804 (external sp-dif like a tv or something like that). All other pins would be passed through, but the i2s lines would be switched via gpio so that OS developers could add input switching.

For me this would make it possible to have simple stereo setups next to every TV in the house. Open source sonos alternative using old speakers etc...
 

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iancanada

iancanada

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gwikse said:
I am looking at the sketchup rpi isolator model again. Are there any changes that have been done on the actual board since I made the model ages ago so that it does not look right to you IAN?

https://3dwarehouse.sketchup.com/mo...DSD-Isolator-by-DIYaudio-member-IanCanada-WIP

As for other projects I wish was done by someone there is a clear no1; coax / optical input + wm8804 + i2s switch from RPI`s I2S lines (underneath) to the wm8804 (external sp-dif like a tv or something like that). All other pins would be passed through, but the i2s lines would be switched via gpio so that OS developers could add input switching.

For me this would make it possible to have simple stereo setups next to every TV in the house. Open source sonos alternative using old speakers etc...
Click to expand...

Hi gwikse,

The 3D model looks very very nice. It makes me feel really good seeing it again after months. Thanks!

Here is the update of IsolatorPi. Just hope you like it :)

Regards,
Ian
 

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C

Cheng

Member
Joined 2004
Sucessfully tested Isolator Hat

Hi Ian,

I have tested the Isolator Hat with my RPI setup and I can confirmed it works magnificently after some figuring. I will post some the step by step (with picture for illustration) process of my test setup in the next few post :)

Rgds
 

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Y

Yatsushiro

Member
Joined 2016
Cheng said:
Hi Ian,

I have tested the Isolator Hat with my RPI setup and I can confirmed it works magnificently after some figuring. I will post some the step by step (with picture for illustration) process of my test setup in the next few post :)

Rgds
Click to expand...

Have I missed something here? How is it that you have one, are you on the test program?

Looks like you are running the same set up as me, with a Kali and Mamboberry LS+

Now I'm keener than ever for my two isolator boards...
 
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