Thursday, 3 January 2019

Auna AV2-CD508BT Hi Fi Amplifier to High End Preamplifier AUX bluetooth

How to made an economic High End Preamplifier.

My Auna CD508 project: from Hi Fi power amplifier to High End Preamplifier with Phono MM and MC.
The original amplifier has a switching power supply, the input selector is made by CD4052 and power amplifier is made by Texas Instruments AB class IC, LM1875 in bridge connection. The power rails voltage are +16/0/-16 Vdc and it as some features like tone control, BT connection balance, remote control , motorized volume knob, output relay, 3 inputs(4 with BT) , a tape recording output and a headphones out.
Estimated  power output on 8ohm should be around 50W/CH.

Amplifier Auna AV2-CD508BT before mod

I dismounted the power amplifier section and I made a substitution with my Espritaudio Preamplifier modules: ESPRE

Preamplifier Auna AV2-CD508BT after mod

Bridge connection of LM1875