The external appearance of this small module with an LC display almost belies what it has inside: a complete stereo preamplifier and final amplifier with IR remote control, adjustable tone, volume and signal levels, and an output power of 2 x 20 W (Class D), all with a single 12-V supply voltage. This makes it perfect for use in a car, boat or motor home.
issued: April 7, 2010
Constructors should note that the Modulo-D amplifier will only respond to commands sent by an RC-5 compatible remote control for CD players.
issued: April 28, 2010
The schematic in Figure 1 and the parts llst should be corrected as follows
R22,R23 = omit
C15,C24,C31,C32 = 220pF
These corrections do not apply to Modulo D units supplied by Elektor.
- 2 x 20 W continuous output power with 4-Ohm loudspeakers
- remotely controlled bass, treble, volume, and preset signal level
- can be used with RC5-compatible remote control transmitters
- all functions digitally controlled by an ATmega8 microcontroller
- operating status displayed on a three-line LC display with 20 characters per line
- stereo input on Cinch sockets
- auxiliary input on a pin header (selectable under software control)
- display board with IR receiver can easily be fitted separately using a 10-way flat cable
- expansion port for extensions, such as an MP3 player or manual control
- open-source firmware enables individual extensions for specific application areas
- extremely compact because no heat sink is necessary
- dimensions (module without enclosure): 65 x 40 x 35 mm (2.3x1.6x1.4 inch)
- efficiency up to 93%
- operating voltage range 11–14 V
- can be used with an onboard vehicle electrical network or an inexpensive 12-V power supply (4 A min.)