I am planning to build a little Volumio box to listen to digital music, spotify, etc. through my living room hi-fi setup using the new RPi 2. I’ve been looking around the forums and while adding a DAC to the raspberry makes perfect sence, I can’t find why so many people are adding a dedicated PSU. Is it to get the most out of the DAC? Lower noise level?
Yes, adding a transformer and linear power supply ensures that the project gets all of the power it needs. There are also significant noise reduction benefits to this route.
Thanks a lot!
Linear PSU with transformer does not add extra power as digital/switching PSUs are cheaper, more eficient and even more powerfull in same budget limits compared to linear. With reliability and stability they give to op-amp on the chip all it needs + dedicated audio PSUs don’t deliver various types of noise.
Such prebuilt PSUs are pricey. If you are able to DIY, this is a good project to start with (bulk order is planned in near future): http://www.diyaudio.com/forums/group-buys/264185-squeezebox-touch-psu-8.html#post4218506
If the price and lack of DIY skills are problem for you, I would go for lower noise industrial PSU (prices start at 20 EUR) and DAC with built in low pass filter/low noise regulation circuit. Good example is: http://www.ebay.com/itm/DAC-24192-ABR-I2S-Input-DAC-Ultra-Low-Noise-Regulation-Low-Phase-Noise-Clock-/331262327691?ssPageName=ADME:X:RTQ:US:1123