I use two powersupplies for my Hifiberry Dac+ Pro:
-5V for the analog part of the Hifiberry Dac+ Pro (Lineair Power Supply)
-3.3 V for the digital part of the Hifiberry Dac+ Pro (A123 Lifepo4)
My question is: Does it damage the Hifiberry when I switch on the two powersupplies one by one, not simultaneously, with a few seconds in between? Or should I turn them on simultaneously?
I hope someone can answer my question!
-5V for the analog part of the Hifiberry Dac+ Pro (Lineair Power Supply)
-3.3 V for the digital part of the Hifiberry Dac+ Pro (A123 Lifepo4)
My question is: Does it damage the Hifiberry when I switch on the two powersupplies one by one, not simultaneously, with a few seconds in between? Or should I turn them on simultaneously?
I hope someone can answer my question!
DJ,
I run mine with 3 power supplies:
5v for the analog portion of the HFBD+P
3.3v for the digital portion of the HFBD+P
5v for the R-Pi
My supplies for the D+P switch on simultaneously. I don't believe there is an issue if they don't come on together, but cannot answer that from my experience.
I do find that I need to power the Pi first, then fairly quickly (within about 10 seconds) power up the DAC supplies. If I don't follow this sequence, the active LED (green?) on the DAC board sometimes does not turn on and the DAC does not work. If that happens, I just power it all down and repeat.
Sorry I cannot answer your specific question, but the Pi-DAC sequencing in my setup is sufficiently critical that I thought I should respond about that.
Greg in Mississippi
I run mine with 3 power supplies:
5v for the analog portion of the HFBD+P
3.3v for the digital portion of the HFBD+P
5v for the R-Pi
My supplies for the D+P switch on simultaneously. I don't believe there is an issue if they don't come on together, but cannot answer that from my experience.
I do find that I need to power the Pi first, then fairly quickly (within about 10 seconds) power up the DAC supplies. If I don't follow this sequence, the active LED (green?) on the DAC board sometimes does not turn on and the DAC does not work. If that happens, I just power it all down and repeat.
Sorry I cannot answer your specific question, but the Pi-DAC sequencing in my setup is sufficiently critical that I thought I should respond about that.
Greg in Mississippi
I think by connecting the 3.3V power supply to GPIO pin 1 AND 17. (I did not do this myself yet, still waiting for a 3.3V battery).
Regarding 3.3V supply.
I think you can neglect PIN 17. That one powers the EEPROM only as far as I've seen it.
I doubt that it'll impact the performance.
The Pin 1 rail powers DVDD and the clocks. You might split that rail.
Regarding 5V.
Using a 5V LDO for AVDD makes no sense.
Better pass the onboard LDO by or remove it altogether and also use straight 3.3V instead.
I think you can neglect PIN 17. That one powers the EEPROM only as far as I've seen it.
I doubt that it'll impact the performance.
The Pin 1 rail powers DVDD and the clocks. You might split that rail.
Regarding 5V.
Using a 5V LDO for AVDD makes no sense.
Better pass the onboard LDO by or remove it altogether and also use straight 3.3V instead.
Hello to everyone!
I just found this thread on the hifiberry forum https://support.hifiberry.com/hc/en...6543509-Digi-Linear-Power-and-DAC-Suggestions
where there was a link to this diyaudio.com thread. I am planning to build a PSU for my Pi3 and the DIGI+ but now I am just wondering what would be the best way to do that. So here you are all talking about modification for the DAC+ where the power supply is more important but as i use the DIGI+ and an external DAC (Audiolab MDAC+) I am not sure if such big modifications are needed.
I think an external +5V supply like this one from ebay
5 Amps Voltage Regulator Module Output 1 5 32V LM338T | eBay
connected to the micro USB of the Pi3 is "enough"? Scott also mentioned that it might be even better to connect the 5V to the DIGI+ and power the Pi3 over the GPIO connection?
I hope you guys can tell me whats the best way.
All the best,
Philip
I just found this thread on the hifiberry forum https://support.hifiberry.com/hc/en...6543509-Digi-Linear-Power-and-DAC-Suggestions
where there was a link to this diyaudio.com thread. I am planning to build a PSU for my Pi3 and the DIGI+ but now I am just wondering what would be the best way to do that. So here you are all talking about modification for the DAC+ where the power supply is more important but as i use the DIGI+ and an external DAC (Audiolab MDAC+) I am not sure if such big modifications are needed.
I think an external +5V supply like this one from ebay
5 Amps Voltage Regulator Module Output 1 5 32V LM338T | eBay
connected to the micro USB of the Pi3 is "enough"? Scott also mentioned that it might be even better to connect the 5V to the DIGI+ and power the Pi3 over the GPIO connection?
I hope you guys can tell me whats the best way.
All the best,
Philip
Do you mean that is better to remove the 5V to 3.3V regulator (ADP150) from the Dac+ Pro (U2) and use 3.3V instead? And if you mean this, do you recommend to feed the complete Dac+ Pro with one 3.3V powersupply or is better to use two of them?
What I'm saying is you'll have several options.
And of it is to power the entire DAC with 3.3V. If you do that with 1,2 or 3
separate sources it's up2you.
Generating first clean 5V with an external LDO for AVDD that gets downsized to 3.3V doesn't make any sense.
And I doubt that cutting off Pin 17 for the EEPROM makes any sense. You'd just have to solder a bridge to PIN 1 anyway.
And of it is to power the entire DAC with 3.3V. If you do that with 1,2 or 3
separate sources it's up2you.
Generating first clean 5V with an external LDO for AVDD that gets downsized to 3.3V doesn't make any sense.
And I doubt that cutting off Pin 17 for the EEPROM makes any sense. You'd just have to solder a bridge to PIN 1 anyway.
A couple of quick thoughts on powering the HFBD+P card with separate 3.3v.... First, Soundcheck, I'm not sure that pin 17 only connects to the EEPPROM. If you look at the picture attached here that shows the underside of the board where I cut the traces, notice the trace going off from Pin 17 to the via. Then look at the picture where I haven't yet connected separate 3.3v power into the board and see that via comes up through the 'e' in HiFiBerry. That area of the board is the land and traces that feeds 3.3v to at least some of the DAC 3.3v pins. So AFAIK, if you leave pin 17 connected but provide separate power to the DAC 3.3v, you'll put the new supply in parallel with the Pi 3.3v via that via, not a good thing!
Related to that, AFAIK also, the 3.3v for the clocks comes all the way around the connector pins to the clocks. BAD ROUTING, IMHO!!!. Notice in the picture that shows after I added the 3.3v feed where I put in a wire to the clock power land from near to my 3.3v power entry... A theoretically much better setup, although I don't know if it would be audible.
On replacing or bypassing the on-board 3.3v regulator, I did not because in my experience distance between a regulator and the fed circuits is about as important as regulator quality, especially for digital circuits. While the ADP150 is just an OK regulator by current standards, I was not going to be able to put my replacement 3.3v regulator as close to the PCM5122 as it is. So I decided to keep it in place and feed it with a much better 5v source, along with upgrading the associated on-board capacitors. If one used one of the small-sized 3.3v regulator boards (Acko's AKR75, Ian Canada's TPS7A4700, and the offerings from Dexa, Belleson, Twisted Pear, and Paul Hynes all are good options) where you could place it as close or closer to the DAC chip, that would be a better solution than what I did.
Pistollero, these pictures also show how I converted mine to run off a separate 3.3v supply...
1. Carefully cut the three traces on the back of the DAC card as shown. An alternative is to remove or bend pins 1 & 17 so they don't connect to the DAC anymore. CHECK THIS WITH YOUR METER BEFORE YOU PROCEED!!!
2. Feed 3.3v into the card. I fed it into Pin 17 with Pin 20 as the ground.
3. Link the 3.3v into the clock 3.3v land, as shown in my 3rd picture.
Again, you will get your best results with a regulated supply that is very close to the board... mm matter here, not cm or inches! If I were using an iFi unit (and I totally agree with Soundcheck that they are very good power supplies and beat a lot of bog-standard linear supplies), I'd go with one at 5-7v output and have the final 3.3v regulation mounted right on the DAC board.
And IMHO, you will get the best results with separate supplies and regulators for the digital and analog sections of the board, but a good single supply with separate regulators should still be good step up from the R-Pi 3.3v power feeding the DAC 3.3v and clocks!
Greg in Mississippi
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Hi Greg thank you very much for your explanation. I m not for electronics but i understand the basics.
I m only using the i2s out from the dac pro so i want to optimize that part of the board.
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Erm, I haven't updated that since way back when. It will have diverged from rpi-4.4.y HEAD. I'll look at re-basing everything to the current rpi-4.4.y HEAD when I get a chance.
And to be honest with you, I'm not really interested in rpi-4.4.y now. I'm running 4.6 kernels. I'll push my 4.6 tree when I have time and post a link for you. (Won't be today. I need to remove the code that cannot be published as Open Source before I push a "public" tree.)
Now here is something worth trying with this DAC which works very well with its sister DAC the PCM5102 when I have tried it.
The charge pump can be easily disconnected from the negative feed to the analogue output stage by removing the cap between Pin 2 and Pin 4, This leaves the charge pump still switching but not drawing any significant current or connected in any way to the negative supply (pin 5). A separate negative 3,3volts can then be applied across the cap from pin 5 to ground. This really cleans the sound up by making the supply to the oscillator more stable as it is no longer supplying current to the charge pump, and it also removes any charge pump switching pulses from the negative power inputs to the output stage opamps or the 0volt rail.
John
The charge pump can be easily disconnected from the negative feed to the analogue output stage by removing the cap between Pin 2 and Pin 4, This leaves the charge pump still switching but not drawing any significant current or connected in any way to the negative supply (pin 5). A separate negative 3,3volts can then be applied across the cap from pin 5 to ground. This really cleans the sound up by making the supply to the oscillator more stable as it is no longer supplying current to the charge pump, and it also removes any charge pump switching pulses from the negative power inputs to the output stage opamps or the 0volt rail.
John