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Consequent powering of HIFIBERRY DAC+PRO

Robert Görig

January 19, 2017 09:07

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Hello, Hifiberry-Team!

I just have purchased the DAC+PRO and like to power it as good as possible.

 

1) There is free space for a capacitor after the 5V/Ground-Connection P3.

Is it needed and if yes, which value is recommended?

2) When I connect a regulated 5V power supply to P3, is there additional regulation on the board?

3) In order to power the Pi separately from the board, I will desolder R14. I assume, that I then would be able to connect isolated extra 5V and Ground for the Pi directly on the DAC-board to power it up from the GPIO side, right? (5V after desoldered R14 resistor for DAC, another 5V rail before desoldered R14 resistor for the Pi)

Where are the 5V and Ground-Pins (on second contact row) located on the DAC-board to power up the Pi?

4) I also want to extra power the 3.3V-demand on the dac- Therefore I will bend away the 3.3V pin on the GPIO-header of the pi. Where do I then have to atach separate regulated 3.3V and Ground on the DAC?

Will there be further regulation on the board also in this case?

 

A lot of thanx in advance!

Greetingz, Robert

 

 

 

 

 

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26 comments

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  HiFiBerry team January 19, 2017 12:35

  1. The capacitor isn't needed, otherwise there would be one. Feel free to experiment with an additional capacitor.

  2. Yes, there is an ultra-low-noise 3.3V regulator on board that powers the analog part of the circuit.

  3. Ground of the Raspberry Pi and the DAC+ always needs to be connected. You can't just power the DAC+ from a floating voltage. Voltage reference is always GND.

  4. The board isn't designed to add a separate 3.3V power supply to it.

  Best regards,
  Daniel

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  Robert Görig January 19, 2017 12:40

  Thanx, Daniel!

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  Robert Görig January 19, 2017 18:29

  Hi Daniel!

  I know you have your attitude- and I understand that. But if 3.3 V can be supplied by the Pi from a GPIO-pin, it must be possible to feed the DAC with separate Power supply. I think, that the kind of powering this point would be effective. From which path are the clocks powered? Also from the Pi (3.3V) or from a regulator after P3? I've no problem to destroy the board- will order a new one;-)

  Thanx and please don't worry;-)

   

  Greetingz, Robert

   

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  Robert Görig January 19, 2017 18:37

  I just want to turn out everything, your board is capable of...it has big potential. The whole thing about high end audio is building up a monster-psu. Nothing else (and that's expensive- so a huge amount of components are suffering from lacking power, they would need). I've experimented for decades- and the really important thing in bringing good circuits to sing is the way you power it! 

   

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  HiFiBerry team January 20, 2017 08:06

  Hi Robert,

  this has nothing to do with "attitude", the board isn't design to power the 3.3V digital part idenependent from the Raspberry Pi. You can cut off all 3.3V pins on the Raspberry Pi GPIO, that's the only way to completely decouple the power supply for the digital part.

  Best regards,
  Daniel

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  Robert Görig January 20, 2017 08:44

  Thanx, Daniel! Can I assume, that the second row on the DAC beside the GPIO-connector is a perfect and working mirror of the connected row?

  Greetingz, Robert

   

   

   

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  HiFiBerry team January 20, 2017 08:45

  Yes, it is.

  Best regards,
  Daniel

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  Robert Görig January 20, 2017 08:51

  So if I cut off all 3.3V-connectors of the Pi3 and power all 3.3V-connectors on the 'mirror' with a separate ultra low noise 3.3V-PSU, I would have what I want?

   

   

   

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  HiFiBerry team January 20, 2017 08:53

  Yes.

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  Robert Görig January 20, 2017 09:03

  So only one more little question: The two 3.3V access points on the Pi3- is there a 3.3V regulator for each of them on the Pi3, or are they powered just from one source- so to say together connected in genuine?

   

   

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  HiFiBerry team January 20, 2017 09:04

  They are powered from a single regulator.

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  Robert Görig January 20, 2017 09:09

  Thank you very much! I'm excited and full of ambition;-)))

  Greetingz, Robert

   

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  Robert Görig February 01, 2017 11:50

  Hi Daniel!

   

  Please, to which pins ground is routet from the 3,3V-powered sections on the Dac+ Pro?

   

  Greetingz, Robert

   

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  HiFiBerry team February 01, 2017 13:06

  Hi,

  GND is connected to all GND pins of the GPIO connector.

  Best regards,
  Daniel

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  Jim Meader February 01, 2017 16:30

  I have the PI3 with a HIFIBerry DAC Pro + 

  I used exact copy software to digitize my cd's  this offers any file format you want at very high resolution, I chose the  MP3 file format  because I play music from many different sources and that file format is easiest to use

  The Dac Pro connects to a sound equalizer with a  Klipsch 12 inch sub, and the the stereo signal is then sent to a Crown XLS 1002 digital amp

  I use 20 year old Mission Argnauts   which are 4 ohm speakers

  http://www.stereophile.com/content/mission-system-mission-780-argonaut-loudspeaker#tRd81PmYLrh6o7hv.99

  I used the normal RPI power supply and all sounded great

  I just added this 5 volt power supply and with the same music files - there is more music/sound coming from my system, I would say the soundstage seems more defined and you seem to hear more detail in the music

  http://www.stereophile.com/content/mission-system-mission-780-argonaut-loudspeaker#tRd81PmYLrh6o7hv.99

  I cut a old computer grounded power cord for the power connection and did the same of the USB power connection to the PI

  key to good sound is starting with good source material and processing it thru a well configured system

  Mine works, I do not think I will make any further changes

   

   

   

   

   

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  Robert Görig February 01, 2017 16:42

   

  Thanx, Daniel!

   

  Greetingz, Robert

   

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  Robert Görig February 01, 2017 17:06

  Hi, Jim!

   

  Thanx for your comment!

   

  I also use Exact Audio Copy and the Aqvox-CD-Ripper (a fully serviced old Plextor-device) with optimized power supply for ripping my CD's;-)

  I store wav-files only. In addition I'm streaming Tidal Hifi in lossless-flac-quality and it's sounding awsome- I am hardly able to hear any difference between Tidal-streaming and my wav-rips. Tidal is something really great and offers access to over 40 Million songs;-) For streaming I use Bubble UP'n'P with the fabulous Moode-Player (MPD-based) on also an RPi 3;-)

  I've gained much experience while optimizing a Soekris 1021 DAM. This board profits from every little upgrade! So I got the ambition to see what's really possible with a Hifiberry DAC+ Pro. It has good potential cause there are no capacitors in the signal path and it comes with precise clocks to avoid jitter. 

  Engaging such clocks and powering them via the 3,3V regulator of the Pi seems to me as too much 'good enough attitude'. Especially the digital part with integrated clocks is a very sensible circuit. I know it sounds allready great without this extra tuning, but I want to see how far I can get and what results are to achieve with the maximum upgrade;-)

  I will provide completely separated, clean and ample power to the Pi 3 (5V), the analogue part of the DAC (5V) and the digital part (3,3V). We'll see- hearing is believing;-)

   

  Greetingz, Robert

   

   

   

   

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  Jim Meader February 01, 2017 18:07

  from what I have read on line - this linear power supply connected directly to the DAC provides the best measured output but for me the price does not warrant the benefit

  https://www.sbooster.com/sbooster-ultra/

  there is a way to connect that also powers the PI but the modification void any warranty from HFI Berry, but may be worthwhile as worst case you just buy another HIFI Dac Pro

  there are a few YouTube videos on this and the way to make the power connections

  BTW I just downloaded the latest Moode image which has some upgrades and all works well. Just and FYI had to use a PC to burn the image as the same image burned on my Mac did not work- Why I have no clue 

  Also in Moode I have turned off my wifi  & USB as I have no usb be connections just hardwired network, but left the HDMI signal in case I need to see the PI on a monitor, but no HDMI connection is currently used.  Why - all these items draw power from the PI circuit so to maximize what can be used by the DAC I made these changes

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  Jim Meader February 02, 2017 17:44

  Here is a link to the power supply I used  5Volt 24 Watts

  http://www.frys.com/product/8381647?site=sr:SEARCH:MAIN_RSLT_PG

  I used a voltmeter on the output terminals going to the PI during heavy usage and it was rock stable at 5 volts

  So the PI is getting everything that it wants from this power source

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  Robert Görig February 03, 2017 07:20

  Hi Jim!

   

  Looks stable and is effordable. I build up own powersupplies based on linear regulators and transformers. Don't trust the switching types. The Velleman puts out up to 200mV Ripple- that won't cause a problem as it feeds the ultra low noise regulator on the board.

   

  Greetingz, Robert

   

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  Jim Meader February 03, 2017 22:58

  While I did notice a difference ( characterized as more music detail ) the difference was nominal and I could be more than satisfied without the new amp. The new amp fits within my cost / benefit window so it works for me.  Bottom line I think the Velleman or any other substitute switching amp that provides more than the standard  5 volts & 2.5 amps, just provides more headroom power within which the combo PI- DAC operates. This would be a benefit under load conditions only. A simple analogy would be hitting a nail with a 1 lbs hammer versus the same nail being hit with a 2.5 lbs hammer, the heavier hammer would feel different and would drive the same nail further into a piece of wood. 

  If I had the knowledge and capability to build my own Linear amp, there is no question I would build it.

  Having said that, separating the PI from the DAC at a power level may provide some additional measurable benefit which may or may not be heard in any giving steup or room. 

  Getting the most out of anything can be an enjoyable and rewarding challenge, so will be very interested in what you find with the changes you plan.

  BTW what do you feel are the key Moode settings for your setup  Thanks in advance

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  Robert Görig February 06, 2017 09:04

  Hi Jim!

  As I play Moode via ethernet-cable, I've disabled Pi 3's onboard-WIFI in 'settings'.

  Also I've disabled HDMI and 'search for eth0'. In MPD I've disabled 'volume', 'volume normalization' and 'resampling'.

  The only thing I've left enabled is UPNP-rendering- for streaming Tidal in 'audio'.

  It's a good idea to set static IP in 'networks'.

  Further I'm using 'Advanced Kernel' and 'FIFO' as time scheduler in 'system'

  I'm happy with the sound.

   

  Greetingz, Robert

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  Robert Görig February 06, 2017 09:17

  Hi Daniel!

   

  In order to  bring my power-tweaking to an end: If I power the two 3,3V pins (on the additional connection-line and with cut off 3,3V-pins on the Pi) each with two separate 3.3V power supplies and connect each PSU's ground to a ground-pin near to the 3.3V-pins, would then be power to (digital part) of Chip and Clocks separated? I'd like to even separate the Clocks from the PCM 5122 concerning powering;-)

   

  Greetingz, Robert

   

   

   

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  HiFiBerry team February 06, 2017 09:22

  Hi,

  no the digital part of the DAC and the clocks will always be powered from the same 3.3V power supply. They can't be separated. 

  Best regards,
  Daniel

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  Robert Görig February 06, 2017 09:24

  Ok, thanx, Daniel!

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  Robert Görig February 09, 2017 17:02

  Hi Daniel!

   

  In order to power RPi 3 via the GPIO-pins (DAC + Pro's 5V are separated- R14 removed), I soldered a header to the adequate second row contacts 2,4,6.

  Now I recognized, that the ground trace from there to 'original' pin 6 is very thin. Can't imagine that this provides suitable grounding for the Pi. Wouldn't it be better to bend over the 5V and ground pins of the Pi (2,4,6) and connect the Pi's PSU there to get a more stable ground trace? 

  Greetingz, Robert