Hi. Here is my complete design of volumio in a box 
Inside and features:
- Raspberry Pi 3
- Allo Boss DAC v1.2
- transparent black plexi front panel
- dual linear 5V power supply based on LM338 and LM7805 (for raspberry Pi and microcontroller)
- backlitghted Touch keys to control device from front panel (based on TTP223B red PCB boards)
- small OLED display with touch button, OLED is connected to Atmega644 via I2C for power and lock status (left upper corner, children protection can engage from ir remote by pressing key for 2 sec.)
- 2x20 vaccum fluorescent display with big characters (pydPiper plugin)
- Atmega644 Microcontroller (used for power management, controlling player via touch buttons and IR remote)
- 2 backlighted USB ports on the back of player (orange illumination is on when volumio is running)
- external WIFi antenna with u.FL connector (u.FL socked was also soldered in to raspberry)
Player is using a microcontroller for power management and interfacing from physical touch buttons - i can turn on and off device, change next previous track, pause or play a track or change volume level from touch buttons or IR remote. Atmega is sending or recieving data by UART interface thru a level converter wich is connected to raspberry pi UART pins. That makes possible to send and receive commands to each other.
An enclosure is taken from old polish 5 band equaliser wich was a part of typical 90’s stereo sound syetesm produced in my country
There is few PCB inside like:
- AC relay board with filter
- power supply board with capacitor filters, linear stabilisers and small 2W trafo for powering an Atmega
- microcontroller board with touch buttons, ir receiver
- DAC mainboard to split other pins from raspberry pi (here is a 3.3V to 5V level converter for UART, additional high current USB port for 2,5" hdd and VFD display connector)
This palyer is a part of my DIY 2.1 sound system with active subwoofer.
Time for some pictures
By hardware player is almost finished. There is only one hole at backof player in which I can insert ethernet or hdmi and dont know wich is more important Another thing is to repaint back of player and make indications.