Phono Preamplifiers

Nagra’s heritage dates back to 1951, when Polish-born Swiss engineer Stefan Kudelski invented the first Nagra I portable tape recorder (the Polish word ‘nagra’ translates as ‘will record’). However, the now-iconic Nagra ‘modulometer’ was not present on either the Nagra I or II models, though the latter did include a level meter with a moving-coil ‘needle’. In 1957 the Nagra III tape deck debuted a recognisable ‘Modulation Level Meter’ – mono, of course, with a single needle.

Here’s a description from the original manual: ‘The upper scale on the meter is for measuring the input level (on Test or on Record), and the output level for Hi-Fi playback. Normally the pointer will not reach the black segment between 0 and +2dB, which is the region of over modulation. The recorder has a safety factor of about 6dB, so that an occasional accidental incursion into this region is of no consequence. The level control should be adjusted so that the pointer only reaches the black zone on the loudest parts of the recording’.

Fast-forward some 70 years and the HD Phono’s modulometer, with black- and red-tipped needles for left and right channels, respectively, displays the selected audio output level only, its ‘Reference 0dB’ point rated at 1V.