Preamplifier

Model: "ALPA MII". Co-project with Alfred Homsma.

8 input channels (relay switched):

• Channel 1: phono input for MD or MC elements (selectable by jumpers)
• Channel 2-6: auxiliary inputs
• Channel 6 can be configured (by jumpers) as pre-out for a headphone amplifier
• Channel 7: connected to internal media server (Raspberry Pi)
• Channel 8: connected to internal Bluetooth receiver

3 outputs (relay switched):

• Channel A or B selectable via app or InfraRed commands 
• Channel C: always available (e.g. for subwoofer). Can be set to mono by jumpers

Channel selection by push button on front panel or via InfraRed commands

Support for various InfraRed remote controls, e.g. Philips, Sony, NEC.

Volume control by rotary encoder, app or via InfraRed commands

Volume indicator by NeoPixel LED ring (24 LEDs). Volume and channel LED’s are turned off after one minute of inactivity.    

Built-in media server (Raspberry Pi):

• Logitech Media Server software (or whatever streaming software you want)
• HifiBerry DAC+ Pro or DSP board; power supply modified to achieve high-end performance
• Music files stored on external SD USB card(s)
• Spotify support using Spotty plugin
• Plugin to allow streaming from Spotify app on smartphone or tablet
• Internet radio
• CD player controlled by Logitech Media Server plugin, automatically started when CD is inserted
• A LED on the front panel indicates if Raspberry Pi has started

App (created with Node-Red) for ripping CD's. Track information and CD cover are retrieved automatically.

Room correction possible if DSP DAC version used.

No tone or balance control

Power supply by 5V/3A net adapter

Documentation:

• Documentation electronics
• User Manual (Dutch)
• https://github.com/PauLL54/PreamplifierAndMediaStreamer
• Acrylic panels and case
• Power supply modification HifiBerry DAC

App, written in Node-RED, for ripping CD's and selecting room correction filters: