Raspberry Pi Power Modification

I'm using Raspberry Pi 2 model B, with Picore Player installed, as a simple network player. It's receiving stream from network then transmitting to dac via usb connection. Briefly it's acting like a bridge without hard drive connected. if you're using a usb dac, then you sure connecting hard drive to other empty usb port is a terrible way, killing whole thing !  For other connection types, lets take I2S or Spdif (needs optional interface) still we have noise & cpu stress (due to I/O processing) coming from hard drive.

Ok let's get back to our topic. In standard configuration the Raspberry Pi is powered by a +5v dc micro usb supply. Alternatively you can provide dc power though the gpio header pins 2 and 6 relatively plus and negative. For more information check here.  

For type 2 model B average power consumption is between 700-1000mA depending on what peripherals are connected. You can simply connect a 1.5A  / 5vdc+ linear regulated power supply and enjoy yourself.. You will clearly feel noise reduction which makes darker background and slightly more musical presentation.

The next step, I call it advanced mode, may be torment mode :) because you will have a high chance to destroy Raspberry, is replacing on-board regulator and a few other things with high quality low noise regulators or power supplies.

For Raspberry 2 model B only !!

Components I marked with red cross seen on the image above have to be completely removed for fresh starting. In the middle there is a noisy switch mode "12 legged" regulator needs to be removed first. It takes +5v dc coming from micro-usb or gpio  header pins, provides three dc voltage outputs +1.8v, +3.3v and +5v.  After that we will remove two inductors (labelled L1 & L2) located serially on regulator outputs. Than we will be ready to supply those three voltages externally.

Yellow wire (on the left side) which was soldered to positive side of L2 is coming from +1.8v power supply. Other yellow wire which was soldered to positive side of L1 is coming from +3.3v power supply. You can solder +5v wires "plus and negative" to the pins of D5. I also added a low esr 330uf capacator (preferably aluminum polymer)  to the legs of D5.

This is the whole picture.  I have high quality +5v external linear power supply connected to my diy Raspberry's enclosure with well made Oyaide power socket. Two circuit boards containing ultra low noise & fast "TPS7A4700" linear regulators are producing +1.8v,  +3.3v  using that +5v dc power.

+9V battery seen on the left side is a part of my battery tweak circuit not related with Raspberry directly. This tweak is here for further noise reduction on ground plane.

Conclusion

I did this modification last year so I had enough time to evaluate what I did. In audiophile perspective this modification is a game changer. You're not just clean up the entire thing, you 're providing a real noise free +5v power to usb hub. Without this modification how good external linear power supply you have is a bit pointless. Your usb powered dac will be appreciated this.

In terms of usability, we have some little drawbacks here. You need to have three good power supply (at least one will be bulky and expensive) and a suitable enclosure. In addition I have to say that I encountered stability problem rarely that needs to be restarted but not a big problem for me..

Update about stability problem (05.22.2017)

Raspberry Pi with modified power section is working rock solid with the new version of Picoreplayer 3.20.  Newer versions also have great supports to overclocks which brings to Raspberry Pi  little more effortless presentation.