Hello!
I'd like to equip raspberry pi and DIGI or DAC each with separate power units.
How is the pin configuration for this aim.
I'm planning a complete separation of power supplies between raspberry pi and DIGI or DAC. I've purchased both hifiberry components and they work without technical problems, but I believe there's more sound potential through optimizing power conditions.
Greetings, Robert
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15 comments
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HiFiBerry team Dear Robert,
you can remove the Pin 2 on the P5 header soldered to the Raspberry Pi and then power the DAC or Digi from the external 5V input on the board. This is the pin beside the "R2" print on the Raspberry Pi. While this might give you a slight improvement on the DAC, I do not expect any changes on the Digi. We even tested it on the DAC and could not find measurable differences as the voltage regulator on the boards works very well. However, you can try it by yourself.
Best regards
Daniel -
Robert Görig Hello Daniel,
as I saw on a schematic Pin 2 delivers 3.3V from Raspberry power supply, am I right? Wy do I then measure nearly 5V at P3 on the DIGI- board?
Doesn't P1 on P5- header deliver the 5V? So isn't it necessary to remove P1 too to get the power supply separation?
Greetings, Robert -
HiFiBerry team You're right, I mixed up the 2 pins. The 5V pin is the one that is near the original P1 header.
Best regards
Daniel -
Robert Görig Thanks, Daniel! -
4Fux Hi guys,
Slightly off-topic: so when I do not remove the pin on the P5 header and when I attach a 5 V PSU to the external 5V input on the Digi board (which I just ordered) I will power both my Raspberry Pi and the Digi from this? No need anymore for the Mini-Usb Power-In of the RPi? Would be great news since the USB Power-in would not fit in the case I've planed!! -
HiFiBerry team Yes, that is correct, it will power both. Just one thing: If you power it this way, there is no fuse protecting the board. -
Robert Görig Hello Daniel!
But, if the board needs the fuse
It's broken anyway- I think this will not happen very often.
To implement right fusing in my
planned PSU for extra powering: Which maximum current is drawn by DAC and DIGI?
Greetings, Robert -
dmitre Robert,
Did you success with external powerfor Digi?
Anyone? -
HiFiBerry team Note that the new HiFiBerry Digi design uses now the 3.3V from the Raspberry. Therefore it is not easy to power the Digi board separately.
Best regards
Daniel -
dmitre ...but still possible to power up from external linear PSU?
Thanks -
HiFiBerry team Yes, this is still possible. It will power the Raspberry Pi and the Digi board.
Best regards
Daniel -
Robert Görig @ dimitre
Hi- yes, separating power supplies has a clear effect- even on the DIGI.
Without separation performance had a slight harshness in high mids and highs.
After modification this characteristics disappeared completely. In addition slightly more
clearness and resolution was noticeable.
With the DAC the improvements were of course far more effective. Especially bass quality and soundstage impression
was increasing. After first listening session with the new power supply it took some 2 or 3 hours to fully develop
the described characteristics- seemed like a burn in effect (Daniel, please ignore this comment;-))
DiY PSU:
https://www.flickr.com/photos/125186975@N06/14141504349/
https://www.flickr.com/photos/125186975@N06/14141803499/
https://www.flickr.com/photos/125186975@N06/14141803759/
Greetingz -
Carsten Hesse Hello Robert,
great work, I am planning something similar. As far as I understand it now, there is no way of "really" separating the power supplies because the Hifiberry still needs 3.3V power from the RPi as discussed in this thread:
http://www.hifiberry.com/forums/topic/does-the-hifiberry-dac-work-when-running-rpi-with-3-3v/
What I am trying to do now is to provide linear power both 5V and 3.3V from an external PSU
(with something like this http://www.diyinhk.com/shop/audio-kits/46-17uv-ultralow-noise-dac-power-supply-regulator-33v55v-1ax4.html)
disable the onboard voltage regulator of the RPi (like described here http://www.daveakerman.com/?page_id=1294) and power the RPi directly from the linear PSU with both voltages. Hifiberry will get its (linear) power from RPi then.
What do you think? -
Robert Görig Hi Carsten!
Sorry for delay- didn't expect any coments here anymore;-)
I think- we won't get satisfying improvements out of this extra 3,3V tuning. Anyway RPi get's better current quality out of the above setup. The problem with the Rpi is a ground issue. Boards like the Pi will contribute noise through processor and peripheral action. There would be still a common ground connection between the Pi and the DAC board through I2S ground connection. G2 Labs have created a ground isolator that is interesting but cost effective. If you want to go for maximum sound quality I would rather recommend a better board and a more sound ambitioned DAC. I just have purchased Cubietruck that seems to be very promising to me (Now with Volumio support:)). Before I tried a G2 Labs BerryNOS1543 DAC with the Pi- that sounds superb. But- no question- for the money the Hifiberry DAC and especially the DIGI are little dream machines.
I'll try to investigate, what I can do with DAC and DIGI to get 3.3V extra- powered in the end;-) The more I consider about it, the more I get nervous;-)
Greetingz, Robert -
Robert Görig Hi Carsten!
I think it's possible to power the Pi via P5 connector (through P1)- after eliminating Digi- board connection from that pin. Extra 5V can then be connected via Digi- board power connectors. So the micro usb power jack is unused as well as the 'worse' regulator and polyfusing? Is there a second regulator on the Pi providing this 3.3V? Daniel said in this former discussion you mentioned, that the 3.3V from the Pi are used with the 'NEW' Digi design. I've got it very early in the beginning of production. Since when did Hifiberry realize this new Digi design? Or did I get something wrong?
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