Jump to content

Raspberry Pi with Hifiberry DAC+ Pro - Using I2S to feed DAC - How to feed with external PSU rails


Recommended Posts

Hello to all,

 

I'm a newbie in this forum, subscribed last week.

 

Recently I bought a Raspberry Pi 2B and a HifiBerry DAC+ Pro. The DAC+ Pro has the ability to output I2S signals, including Masterclock.

The DAC+ Pro also has two seperate audio clocks on board which are triggered by software (latest distro's do support this feature).

 

There's also the possibility to remove a 0 ohm resister and power the analog side of the dacboard externally with 5V.

If feeding with external psu, and NOT removing the 0 Ohm resistor, the external psu also powers the RPI.

 

Since I wanted to provide analog AND digital section of DAC+ Pro with clean, ultra low noise power, I decided to cut off the 3.3V header pins

from the RPI 2B since DAC+ Pro hasn't the option to provide 3.3V externally.

But, sadly DAC+ Pro didn't work anymore from that point. I had to restore 3.3V from RPI to DAC+ Pro before it would work again.

 

 

Does anybody have any clue why I cant power DAC+ Pro with external 3.3V when cutting off all 3.3V lines from RPI 2B ?

 

In the meantime I bought a RPI 3 but didn't cut any headers before I am very sure how to manage 3.3V and 5V externally on DAC+ Pro.

 

Any help is much appreciated!

 

Alex Bartels

The Netherlands

 

 

Link to comment
Share on other sites

Which means?

 

Maybe it's not the right forum, if this kind of answers are common.............................

Knowing there would be more helpful types like @@rastus along I was merely making a quip of frustration having seen some people's Pi experience as all crust and no pie.

 

just ignore me. I have started 3 runaway digital music threads. (and my Gibberfish dosen't do 'tech' too well).

Edited by E.Man
Link to comment
Share on other sites

@E.Man

It's ok, I overreacted I suppose  :emot-bang:

 

 

@@rastus

Thanks for the forum links, I did read them already but no real solution, but it seems others have tried it successfully!

 

 

@@bob_m_54

Pins 1 and 17 are short circuited, so I cut both from header and fed 3.3V to pin1, GND of 3.3V / 5V and I2S  are short circuited too.

 

@@statman

Can you give me an example of what you are good at?  ;)

 

Will try again this evening with RPI2b, maybe I overlooked something or made a faulty connection (which I don't expect....)

It's sad there isn't any ground isolation module for RPI2/3

 

I am about to order Ians FIFO II - Isolator - Dual Dacboard, but I wanted to have the base of the source as much as perfect as possible before connecting Ians stuff.

 

 

Btw, planning to connect it (build it in) to my home brewed little baby:

 

https://drive.google.com/open?id=0B5ivzpgUT3UYU0tMLVdnQ0NodFk

 

 

Thanks for your time guys!

  • Like 1
Link to comment
Share on other sites

Alex Bartels > "...my home brewed little baby..." <---- Frak me side ways! LITTLE?

Hey E.Man > Check that link out! Bet you'd like to dive into that with a screwdriver!

Alex Bartels > Maybe you can help me, I need a linear power supply for my Raspberry Pi 2 Model B and/or DSPeaker Anti-Mode 8033... a combined unit would be a more convenient solution. Thanks in advance for any suggestions!

  • Like 1
Link to comment
Share on other sites

Hello Rastus,

 

It depends on how much your devices drain, below 500mA you could use this one for 3.3v-5V-7V:

http://www.diyinhk.com/shop/audio-kits/89-08uv-ultralow-noise-dac-power-supply-regulator-3357v-15ax2.html

 

I use those in my dac design for ALL power rails. Every power rail fed with separate R-Core (one winding per R-Core), and all R-Cores fed by separate netfilter.

 

 

Netfilters you can use, very cheap and very effective :

https://world.taobao.com/item/36513196086.htm?spm=a312a.7728556.1414651174895.4.5FjkJz&scm=1007.10146.6070.0&id=36513196086&pvid=2d41368f-cbab-4fec-b49f-580e00143f9c

 

 

For DSPeaker you have to find another solution, it needs more amps.

 

 

Hope this helps!

Link to comment
Share on other sites

...

Hey E.Man > Check that link out! Bet you'd like to dive into that with a screwdriver!

...

I can't see any space to fit a screwdriver in there at all.

Hard pushed just getting my earthing to stay put for my phono.  Do you think think blu tac is a temp replacement for solder.  Just needs to hold the connection not form it.

 

My special subject of  'Fat Axl' not being a Buddha didn't go far.

Edited by E.Man
Link to comment
Share on other sites

I can't see any space to fit a screwdriver in there at all.

Hard pushed just getting my earthing to stay put for my phono.  Do you think think blu tac is a temp replacement for solder.  Just needs to hold the connection not form it.

 

My special subject of  'Fat Axl' not being a Buddha didn't go far.

 

Think you'd better solder or screw it. I connected all copper foils to eachother with screws, very handy since I used a separate wooden subchassis (which you can put screws into...) for R-Cores/PSU's/Netfilters and DAC and USB input.

Link to comment
Share on other sites

@@bob_m_54

Pins 1 and 17 are short circuited, so I cut both from header and fed 3.3V to pin1, GND of 3.3V / 5V and I2S  are short circuited too.

OK, I can't find a schematic online for the Hifiberry DAC, as you have obviously seen yourself. I know the pins 1 and 17 are shorted on the Pi, but you are saying that pins 1 and 17 on the hifiberry DAC are also shorted?

 

It seems they are pretty keen not to release any details about the boards doesn't  it..

  • Like 1
Link to comment
Share on other sites

Hello Bob_m_54,

 

I didn't measure yesterday, just listened to the RPI3/DAC+Pro connected to a cheap AK4495SEQ dac.

They need a few more days, but it already sounds VERY promising.

 

Not sure if I can measure tonight, but I will, just to be sure I didn't made a mistake.

For now I can't test it in my dac, it stays at a friends place since a week, and probably won't leave it forever hahahahaha

 

Yes, you are right, they don't release any details about their boards which is really understandable in RPI world.

Just as their statements do: DAC+Pro is hackable, you can power it external (5V), but if you DO solder a 2 pins header onto it, there's NO warranty anymore, hahahaha, what a joke  :)

 

Luckily it's a cheap board, so if something is going wrong, the next day there will be a brand new one arriving at my door  :P

  • Like 1
Link to comment
Share on other sites

Yes, I bought the IQaudIO DAC plus, and have been running mine for about 3 weeks. At first it sounded a bit too harsh to me, but have since been running MoOde on it and it has had time to settle down, and now it sounds very good to my ears. Also I have been lately playing FLAC files and think that may also add to the better sound. I intend to build or buy a better power supply, but maybe just the 5V which might improve it even more.

Cheers

Bob

  • Like 1
Link to comment
Share on other sites

it's a nice looking pcb, but I am afraid it doesn't have it's own clocks? Or am i missing something?

 

Since those dac's are real cheap, a real bargain, maybe just try a HifiBerry DAC+ Pro in the future, just to compare?

There should be a substantial difference between the two, just because of the independent audio clocks the DAC+Pro uses, and price difference isn't that big at all.

 

I hope I can feed 3.3V separate also, that definitely would raise it's SQ to another level.

 

Cheers

Alex

Link to comment
Share on other sites

Yes, you are correct, the IQaudIO uses the DAC PLL to sync, where as the HifiBerry DAC plus pro uses an onboard oscillator, when set to master mode (in slave it also uses the DAC PLL). So the HifiBerry DAC Plus Pro should sound better.

post-154625-0-94853400-1459992146_thumb.

Edited by bob_m_54
  • Like 1
Link to comment
Share on other sites

Yes, you are correct, the IQaudIO uses the DAC PLL to sync, where as the HifiBerry DAC plus pro uses an onboard oscillator, when set to master mode (in slave it also uses the DAC PLL). So the HifiBerry DAC Plus Pro should sound better.

attachicon.gif512X.gif

 

Yes, DAC+Pro has two onboard clocks, one for 44.1 - 88.2 - 176.4 and one for 48 - 96 - 192

Link to comment
Share on other sites

Yesterday measured pin 1 and 17 of gpio and they indeed are shorted. Tried to feed again with 3.3V external but it didn't work.

 

Not sure if its my PSU which delivers 3.2746V instead of 3.3V

 

Measured 3.3V output from RPI which is 3.3217V

 

I'm stuck right now  :(

Link to comment
Share on other sites

Thanks mate  :)

 

With 3.3V external powered it's more airy, more blackness around voices and instruments.

 

 

For the moment I use it with a cheap chinese AK4495SEQ diy dac which only has I2S input.

I used this dac before I build the one in the above picture-link.

 

It's almost as good sounding as my "monster dac" which is connected to isolated xmos (usb)!

Voices have more body, and it seems there are more 3D "artifacts", it's a VERY GOOD I2S interface!

 

Can't wait to connect it to my dac, but, supposedly I'll sell it this evening, so, first have to build me a new one hahaha

 

Have a nice weekend!

 

:thumb:  

Edited by abartels
  • Like 1
Link to comment
Share on other sites
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.




×
×
  • Create New...
To Top