Add the ability to decouple the 3.3v digital side of the PCM5122 from the pi. Same as the analog side, possibly using the same linear 5v->3.3v regulator circuit.
Date
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7 comments
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Alex Bartels Hi Scott,
I have HW version 2.2
Is it possible to feed the 3.3V external?
I plan to remove the 2x ADP150, 1x for 5V, 1x for 3.3V, and feed with ultra low noise (0.8uV) supply.
It probably is best to remove the ADP150's and solder +/- directly to the pcb.
Big question:
Does DAC+Pro needs the ground connections from Pi, or can I cut them (pins 6,9,14,20,25,30,34,39)
Please advise,
Regards,
Alex Bartels
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-Felix- Hi Scott, Alex,
I was asking myself the same questions that Alex posted. I also like the idea of a new HW revision with the ability to decouple the 3.3v digital side.
I built my own TPS7A4700-based 5v+3.3v psu and try to minimize jitter from the oscillators carrying over to the I2S signal. I will use it for an external DAC and won't be using the the D+P's analog side.
Best regards,
Felix -
Alex Bartels Hi Felix, Scott and the HifiBerry Team,
I feed DAC+ Pro externally with 3.3V and 5V.
Would love to feed the XO's separately too.
Wishlist:
1- 3.3V header to feed 3.3V logic
2- 3.3V header to feed XO's
3- Cut ALL GND from RPI so it works with it's own GND
4- Maybe Design an I2S out ONLY with FIFO / Isolator / and High-End grade, changeable XO's, all with separate PSU headers.
I use it with PiCorePlayer feeding I2S directly into my DAC. Don't use Analog side either.
Best sound ever heard!
Regards,
Alex
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Dan Hello Alex,
i also only use the digital part of the hifiberry pro. Therefore I am interesten in your post. How do you feed the digital part, how do you connect it? And with which psu?
greetings, dan
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Alex Bartels Hi Dan,
I did cut off header pins 1 and 17 from RPI3 and feed 3.3V directly on pin1-17 on DAC+Pro, pin6 used as GND
5V fed on header DAC+Pro, removed the 0 Ohm bridge. I use the Diyinhk 0.8uV ultra low noise psu's.
Greetings, Alex
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Lambrusco Hi Alex, which is the 0 ohm bridge? and do you feed the 3.3V on both pin 1 and 17 or just 1?
In which pins you feed the 5V? and where do you link the two different GND?
Thanks
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Alex Bartels Lambrusco,
0Ohm bridge is described in the manual of HFB DAC+Pro, I don't use it anymore, since a long time, and I am not sure
where it was situated at pcb, from my memory it was near the header, in the corner, where you can solder power header for external power.
As said, I don't use HFP DAC+Pro anymore, I completely went I2S route with Allo.com Kali reclocker and Ian Canada FIFO II kit with IsolatorPi.
Hope somebody else can help you.
Regards,
Alex
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