P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

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Re: P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

Postby PeteB » 27 Apr 2016, 20:47

What was the DC-DC converter for, in the first place, maybe so you could supply the board with some higher voltage which the regulator could not handle (?) or am I missing something?

P.
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Re: P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

Postby TommyBoy » 27 Apr 2016, 22:04

pete, they all use a 5V to 5V unregulated type,
so it is like, what comes in, come out (+ noise)
and they connects the two ground in-out in parallel, so it is a noise injector, nothing more,
the 5V from the PI is actually nice and clean the first place, why ruin that ?
the pi is designed for 5V not 4V not 6V, so what you ask for is of no use.
so nope.. I have no answer, what it was there for the first place ??
feeling lost..
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Re: P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

Postby PeteB » 27 Apr 2016, 22:40

I know that the 5V charger-type power supplies can have very poor load regulation and noise, and the Pi can continue to work under those conditions. But the regulator which was after the converter (probably) needs a minimal forward voltage drop to do its job. Perhaps the regulator was there to raise the voltage, not lower it. A poor solution, if that was the reason, not to mention what you found with the ferrite bead. This looks like there is something missing, or something was mis-wired or left out of an earlier design or not copied very carefully when this PCB was laid out.
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Re: P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

Postby rastus » 28 Apr 2016, 00:46

Why would the designers put something there that's not really needed, I mean they pay for the item to and put it on, then we say it's not needed and in fact it would work better without it? Doesn't make sense to me. But then anything to do with circuitry never does make sense to me. I'm really very confused right now (damned Bipolar). I'm confused about... circuitry, why this ferrite bead is there (should it be?), why TommyBoy says it shouldn't be there. I'm even confused about the fact that I sort of understand what he means. PeteB, you know about this shiit (I've read enough of your posts to know that), is this for real? I mean really? Could it be that when they went from the earlier model board (Raspberry Pi Model B with the P5 connector) that they carried over the design to this new model (that does not have the P5 connector)? And, why the Hifiberry card has so little in the way of circuitry. I don't know, I think my jury's still out on this one, plus me and solder do NOT mix. Am I babbling?

HiFi DAC+ HAT – Raspberry Pi 2 & B+ (PCM5122 DAC chip from Burr-Brown Corporation)
http://www.geekroo.com.au/products/1482
Hires pics:
http://www.geekroo.com.au/wp-content/up ... load-9.jpg
http://www.geekroo.com.au/wp-content/up ... load-6.jpg
http://www.geekroo.com.au/wp-content/up ... load-7.jpg

HiFi Digital DAC PiCobbe for the Raspberry Pi (Raspberry Pi Model B, WM8804G chip from Wolfson Microelectronic)
http://www.geekroo.com.au/products/1270
Hires pics:
http://www.geekroo.com.au/wp-content/up ... 165908.jpg
http://www.geekroo.com.au/wp-content/up ... 170231.jpg
http://www.geekroo.com.au/wp-content/up ... 170105.jpg

I notice the Hifiberry DAC+ has a lot less circuitry on the board when compared to the PiFi:
https://www.hifiberry.com/wp-content/up ... 41x441.jpg

Edit:

"This HiFi DAC + expansion board is designed on the base of the old version B DAC expansion board. The new version has upgraded to higher-end chips and circuits, and adds more practical functions, plus higher performance."

"Isolated power supply design, independent power supply for raspberry pi and DAC; Ferrite bead has common ground, which avoids current sound."

https://www.hackster.io/itead/products/ ... spberry-pi
You are invited to participate in my new forum, Rastus' Rants: http://rastus.tk
Subjects covered: Hardware setup for the Raspberry Pi as a digital streamer. Digital music, artists and thier albums or CDs. More will be added in the coming weeks.
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Re: P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

Postby TommyBoy » 28 Apr 2016, 08:26

>Why would the designers put something there that's not really needed,

Designers ? what education level do you think they have ? anyone can copy from the net, it takes 2 hrs to learn how to layout a pcb.

>I mean they pay for the item to and put it on,

they just add the cost, to product, customers then pay a little extra.

>then we say it's not needed and in fact it would work better without it?

You must thrust me, it is NOT NEEDED..

>Doesn't make sense to me. But then anything to do with circuitry never does make sense to me.

I can normally tell you exactly why and what on every tiny part on a pcb, I got the right education levels, and over 30 years experiance
with electronic design.
the more we find out, the more confused we can be :-) Typical with wrong/bad designed stuff.

thanks for the pictures, the GEEKROO P1FI DAC 2.0
also use ferite bead R8, but on your pictures I can not tell it it is in ground ??
or in 5V input, newer the less, they also use the switchmode module, I claim loud and clear :
only do worse !! nothing good comes from this part ! And that is a fact !

The cobber V1.1
they got wiser : no ferite bead, no resistor in the ground, and now see :
the switchmode module is replaced with ferite bead in-out, so they learned from their mistake.

>I notice the Hifiberry DAC+ has a lot less circuitry on the board when compared to the PiFi:

EXACTLY, this is the best design (if you ask me) and my now modified P1FI circuit is made similar to this design
and now it really works and sound is finally good and stable.
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Re: P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

Postby TommyBoy » 28 Apr 2016, 08:37

"Isolated power supply design, independent power supply for raspberry pi and DAC;
Ferrite bead has common ground, which avoids current sound."

SNAKE OIL
look up snake oil in wiki..
They dont even understand what they try to write, so those lines are just rubbish.
Listen : you can not isolate anything with a circuit like this, the critical I2S digital lines need to goto dac chip :-)
the DAC chip is designed to share ground with high performance cpu systems,
the "thing" you do want to isolate, is the positive supply voltage, it is simple, add a little seperate regulator for the DAC chip,
now the DAC peforms as they claim in its datasheet.

I can even say it more simple :
A switchmode supply, is not what any one with a working brain cell, want to put into a HIFI DAC board.
so DONT PURCHASE any of the mentionened dac boards with a switchmode !!
if you allready own one, then modify it, as explainened.
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Re: P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

Postby Slartibartfast » 26 Nov 2016, 06:54

Hi - can I make a query on the hardware changes. I made all the recommended ones and all is working ok but a bit of clarification on the capacitor at C9 would assist me. The recommendation is to change to a 220uF 10V (from the installed 10uF 50V one). Is this ok? I'm referring to changing a 50V cap for a 10V one?

I'd like to thank you for posting this information. I received a DAC card which was DOA. The Mornsun DC-DC unit had failed so removing/replacing it was necessary anyway - thankfully I found this Forum submission!
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Re: P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

Postby Slartibartfast » 29 Nov 2016, 13:34



...and so I made a video of the repair/upgrade. Comments welcomed! :D

https://www.youtube.com/watch?v=CizmwpDXc7o&t=36s
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Re: P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

Postby surfninja » 06 Dec 2016, 20:05

Tommy, I picked up this dac from Amazon for $20 and it seems like it is the cheap version.

I've been using it a lot without any clicks or pops. I have a wolfson DAC too and have no problem listening to this one (mainly FLAC and web radio).
Last edited by surfninja on 18 Jan 2017, 19:49, edited 1 time in total.
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Re: P1FI DAC, I2S, random audio clicks ?(SOLVED READ)

Postby g8chk » 15 Jan 2017, 11:48

Hi
This might not be the exact place to ask this but here goes.
I have a Raspberry PI 3, with a P1F1 DAC+ v.2.0.
Config file edited so runs fine playing mp3s from a usb stick, large black dc-dc converter referred to does not get very hot so is there another answer to the clicks on the audio problem?
Royston
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