AVM INSPIRATION P1.2 PHONO STAGE
You can pay more for a phono preamp but the premium you pay won’t buy you any more tonal accuracy or higher-quality sound!
AVM’s CEO, Udo Besser, refers to it as ‘our smallest guy’, while others within AVM call it ‘our newest ‘baby’, but what they’re all talking about is this German company’s latest phono stage, the AVM ‘Inspiration’ P1.2. As with all phono stages, the purpose of the AVM P1.2 is three-fold: to boost the low voltage from a moving-magnet or moving-coil cartridge to a level that’s highenough to drive a pre-amplifier; to provide an appropriate load for that cartridge, so it performs as its designers intended; and to provide RIAA equalisation to ‘correct’ the music signal recorded on vinyl LPs.
Why do you have to ‘correct’ the signal recorded on the LP? Basically, in order to be able to engrave an audio signal on an LP, the mastering engineer has to dramatically reduce the level of the bass frequencies (gradually from 1kHz until by 20Hz the level has been reduced by 19.27dB) and dramatically increase the level of the high frequencies (gradually from 1kHz until by 20kHz the signal level is boosted by 19.62dB). If this were not to happen, the groove would meander so violently at low frequencies that it would, literally, throw the cartridge out of the groove, while at high frequencies, the sound caused by the stylus scraping over the vinyl would ‘drown out’ the treble. (This is a somewhat simplified explanation, but an exploration of the effects of the constant velocity characteristics of magnetic cutter heads is, I think, somewhat beyond the requirements of this review.) So it’s the job of the phono preamplifier to boost the level of the bass back to where it’s supposed to be, and reduce the level of treble, via a process known as ‘equalisation.’
The equalisation curve that’s used nowadays to perform this function is known as the ‘RIAA equalisation curve’ simply because it was developed by the Record Industry Association of America. Before the RIAA stepped in, different LP manufacturers used different curves, so if you played an LP pressed by Columbia you’d need one curve, then if you played one pressed by Decca, a different curve and then, if you played one by Deutsche Grammophon, another completely different curve again. In fact, at one stage, there were more than 20 different equalisation ‘curves’ in common use, which was obviously a nightmare for both consumers and manufacturers alike. Even as late as the 1970s, some manufacturers refused to use the RIAA-specified curve, which is why some phono stage manufacturers still produce phono stages with switchable equalisation (usually between the RIAA, Columbia, Decca, CCIR, and Teldec EQ curves). In typical AVM fashion, the Inspiration P1.2 (which offers only RIAA-standard equalisation) is beautifully crafted from solid brushed aluminium and the front panel is an exercise in minimalism: there’s just an AVM logo and a small LED that glows when the unit is switched on. In order to keep the noisy 240V a.c. mains power supply away from the phono circuitry, AVM supplies a plug-pack