Preamplifier for connecting a microphone and a line-level source (e.g., CD or MP3 player) for common switch programs, suitable for residential homes, small training rooms, practices, etc. The volume levels of both audio sources can be adjusted separately, and the preamp can also be turned on and off. The amplified signal can then be forwarded to up to 50 AMP 10 (DC) units or, for example, to a 100 V amplifier. Delivery includes a printed cover plate (50 x 50 mm).