Усилители мощности стерео — Lindemann Musicbook 50

The Musicbook 50 is a small two-channel power amp made by Lindemann audiotechnik, based in Krailling, Germany, and the smaller of the two power amplifiers offered in the Musicbook family at the time of the brand's US launch, below the Musicbook 55. The same family also covered the Musicbook 10 and 15 USB DACs and the Musicbook 20 and 25 network players, all sharing 6.5 mm solid aluminium casework built in Germany. The US launch price was USD 3,195, with CAD 3,595 quoted for Canada.

Key specs that matter

The manual gives 100 W per channel into 7 ohm for periods under one minute. Maximum output current is 6 A peak. Gain is 25.8 dB, a factor of 20. The XLR inputs present 10 kilohm and the RCA inputs 5 kilohm. Frequency response runs from 0 to 36 kHz at -3 dB, and THD plus noise is typically below 0.05%. The universal mains input accepts 90 to 264 V at 50 or 60 Hz. Power draw is 0.45 W in standby, 2.5 W at idle, 10 to 20 W on average when playing and 200 W at peak. Its enclosure is 280 mm wide, 220 mm deep and 65 mm high, with a weight of 3.10 kg.

Engineering and use context

Both channels are fully balanced Class D stages built on the UCD circuit concept, which is protected by several patents. The signal path is all-discrete and kept short, and a high-current switch-mode supply feeds the output stages. At the back sit an RCA pair and an XLR pair; active input circuitry detects which one carries a signal, and Lindemann specifies that just one of the two pairs should be wired up at any time. A signal detector with a threshold of about 0.5 mV wakes the amplifier from idle in roughly two seconds, and after 30 minutes without music it drops back to idle. The front standby LED glows yellow and pulses while the amplifier is working. Protection circuits watch the outputs and guard the drivers against damage, with an Error LED that turns red when a fault occurs.

Pairing

The manual names loudspeakers of 6 to 8 ohm as the ideal load and lists 4 to 8 ohm as the permissible range. Sources connect through either the balanced or the single-ended inputs. Lindemann's own Musicbook network players are housed in an enclosure of identical size and offer both XLR and RCA outputs driven by an analog volume stage.

Alternatives

The Lindemann Musicbook 55 is the larger stereo power amplifier of the same Musicbook generation, rated at 240 W into 8 ohm and launched in the US at USD 4,795.