For those of you who are currently using Raspberry Pi based Roon Bridge, do you guys experiencing any electrical noise? I’m currently planning to add two Roon Bridges but a bit concern with the possibility of electrical noise.
I’m also checking on Allo DigiOne Signature HAT or Ifi purifier for a possible solution but the question is, is it really necessary?
Any thoughts?
I have digione running Ropieexl into ifi dsd BL with Pi powered by Allo Nirvana . Power supply was valuable addition and lowered noise floor for system . Also running Ropiee with Hifiberry Dac2 with Nirvana power supply for Pi and very happy with it as well.
My advice would be that any DAC connected to the Raspberry Pi should have its own power. Especially avoid using the USB port on the Raspberry Pi for both signal and power. Many DACs have their own power inputs, but for those that do not, consider the iFi iDefender+ and iPower 5V combo or similar to replace 5V power from the RPi with a clean, stable source.
The degree to which any of this makes a difference to noise floor or sound quality depends greatly on the downstream DAC. Most modern DACs do a pretty good job of filtering dirty power, but it it’s not very expensive to clean things up, and it feels nice to do so. 
Other things to watch out for include preventing SMPS from pushing switching noise onto your power lines and making sure that each component in your system has exactly one path to ground. I don’t have a great way to test for the former, but measuring A/C voltage between chassis or signal ground for each pair of components in your system can identify grounding issues.
I’m running RopieeeXL on a RPi4b. USB out of the RPi into a Schitt Modi 3+.
It works wonderfully well for well under $200.
I’ve got a Pi4 with the DigiOne Signature (using the Digital RCA Audio out) and a Shanti Dual Linear PSU with no noise issues at all. It sounds amazing and can’t be beat at the price. And it’s better than a lot of higher priced options as well.
I’ve got a few Pis and audio HAT devices including the Alloo Digi Sig.
While I wouldn’t put you off it the cheaper HiFiBerry SPDIF/TOSLINK boards sound the same to me. There’s no electrical noise I can detect. I’m using HATs all round, @David_Snyder’s advice sounds solid, particularly on sharing USB data and power. I’m using pretty standard USB power plugs but not the cheapest. You can always upgrade the power supplies if you hear noise.
The Pi2AES is an absolute beast. AES is amazing if you have a DAC that takes it as an input (Yggdrasil and Modius are the ones I know, but I’m a Schiit-Head). I use BNC/SPDIF into my Gungnir MB. Blackground.
Thanks for all of your input guys. I don’t plan on using shared power but I’ll definitely get Allo Nirvana as opposed to using a standard Pi’s power supply. It’s a better solution for the price than paying more for something like iFi iDefender or iFi Purifier.
Before you do, look at Pi2AES - I tried both and slightly preferred the Pi2AES, and it’s fun to build.
https://www.superbestaudiofriends.org/index.php?threads/dummies-guide-to-pi2aes-throw-away-your-pc-or-laptop.8878/
No electrical noise as far as I can detect.