Phonoforforsterkere

Phonoforforsterkere are a type of electronic amplifier specifically designed to boost the very low-level signals produced by a phonograph cartridge. These signals are typically measured in millivolts and require significant amplification before they can be processed by a preamplifier or directly sent to a power amplifier. The primary function of a phonoforforsterker, often referred to as a phono stage or phono preamplifier, is to raise the amplitude of the cartridge's output to a level that is comparable to other line-level audio sources, such as CD players or streamers.

Beyond simple amplification, phonoforforsterkere also incorporate a crucial equalization circuit known as the RIAA (Recording Industry Association of America) curve. During the vinyl record manufacturing process, bass frequencies are attenuated and treble frequencies are boosted to reduce surface noise and allow for longer playing times. The RIAA equalization in the phonoforforsterker reverses this process, boosting the bass and cutting the treble to restore the original tonal balance of the music. Without this equalization, vinyl playback would sound thin and noisy.

There are two main types of phonoforforsterkere: moving magnet (MM) and moving coil (MC). MM cartridges produce a higher output voltage than MC cartridges, and therefore require less gain. MC cartridges produce a much lower output voltage, necessitating a phonoforforsterker with higher gain and often lower noise floor. Some phonoforforsterkere offer switchable settings to accommodate both MM and MC cartridges. They can be integrated into existing amplifiers or exist as standalone external units.