I’m looking to power the raspberry pi and dac with 5v each. Should I look at getting an ultra low noise voltage regulator for each ? Is there a benefit?
Thanks,
Joe
I use a iFi USB Power supply for my BBB.
Made a nice improvement…YMMV
Upgrading PSU brings a benefit 90% of the times.
Simplest solution?
Use an adequate PSU for pi (at least 1A), but nothing too fancy.
And use a separate good quality PSU for DAC. You’ll need a Y USB Cable for that, so it will be connected to PI only for signal.
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For a RPI et al, I’d just buy a iFi USB power supply and be done with it.
It will power the RPI and USB-Powered Dac with clean power. No need to DIY, buy Y-USB cables etc.
One example - iFi powering a BBB and USB/Converter.
BBB plugged directly into the iFi
5v power being supplied to the BBB from the iFi power out
Audio coming from the BBB through the iFi to the USB/Converter
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Another BBB + iFi set-up
Might want to look at Schiit Wyrd for 1/2 the price schiit.com/products/wyrd
Although you’ll need Y Splitter.
Works brilliantly to eliminate noise from PC to DAC (my use case).
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I’ve gotten myself this one. I like the upgrade. This is a very good power supply. It doesn’t split the DAC as the others do here, but it feeds the pie with cleaner power and less noise back into the mains. It works well.
squeeze-upgrade.com/raspberr … anguage=en
What is important is not to have noise in the power supply in the range from 50 kHz and up: the ripple, the noise and so on below that frequency is already taken care of by the (linear) voltage regulator (5V to 3.3V) inside the USB device, since the chips work at 3.3V and the USB feeds 5V.
The point then: how to get rid of 50+ kHz noise/ripple. The answer is: put a ferrite bead in the power cable just before the Pi, in general it is enough. Without it, the noise will pass through and go to the audio chips.
Ferrite beads are easy to find and can be applied easily by yourself.
For example, a good setup would be to find a 6-9V PSU (even an old AT/ATX PSU!! you would use the 12V line) then you put a ferrite bead (or two…) on its output and then you connect the output to this one:
dx.com/p/dc-dc-63v-4-5v-to-6 … red-285016 (of course you need to put a heatsink on the regulator and you need to put in the flow of yir after the old AT/ATX PSU).
and then you put another ferrite bead on its output before the RPi (or the I2S audio card you are using).
The voltage will be cleaner than most commercial PSU can deliver and you will have spent like 20 dollars or less (much less actually). Actually if you do as I said you will have a cheaper but quality-wise way overkill setup. The RPi and the audio card would work well with much simpler setups.
Source: cds.linear.com/docs/en/applicati … an101f.pdf and my knowledge.
(read it, it’s easy to understand, just skip the schematics and get the basic idea if you don’t want to go in detail)
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