Усилители мощности стерео — Marantz AMP 20

The AMP 20 is a 12-channel power amplifier from Marantz, designed as the partner to the AV 20 preamplifier in reference-level home theatre systems. It is built in Shirakawa, Japan, carries a US list price of USD 6,000 and is covered by a 5-year limited warranty on the North American market. The box holds the amplifier, an AC cord, an amp control cable, a remote control cable, a wrench for the speaker terminals and a quick start guide.

Key specs that matter

Each of the 12 channels delivers 200 W into 8 ohm at 1 kHz and 0.05 % THD with two channels driven, and the same 200 W holds at 0.7 % THD with five channels driven. Into 4 ohm the rating is 400 W at 0.7 % THD. Bridging two channels in BTL mode gives 400 W into 8 ohm at 0.05 % THD. The range is 5 Hz to 70 kHz within 3 dB at 1 W into 8 ohm, with 110 dB IHF-A weighted signal to noise. Voltage gain is 29 dB. Input sensitivity is 1.4 V at 47 kohm through RCA and 2.8 V at 100 kohm through XLR. Maximum power consumption is 400 W, idle draw with no signal is 110 W and standby is 0.2 W. The unit measures 442 x 442 x 191 mm and weighs 18 kg.

Engineering and use context

Marantz pairs custom switching output stages, a class D design, with its HDAM-SA2 discrete input modules. Every channel has both balanced and unbalanced inputs, and a selector switch decides which set is active. Three operating modes are available. Normal mode drives loads from 4 to 16 ohm. Bi-amp mode feeds the woofer and tweeter sections of a speaker from separate channels, so their supplies stay isolated from each other. BTL mode bridges pairs of channels for more drive and accepts loads from 8 to 16 ohm. Twelve SPKT-1+ speaker terminals are fitted to the rear, and the chassis is copper plated behind a metal front panel with a level meter in the display. Custom installers get RS232 control, a DC trigger in and out, Marantz Remote Bus and IR flasher sockets, and the amplifier can power itself down automatically.

Pairing

The AMP CONTROL cable supplied with the amplifier links it to a Marantz AV preamplifier so both units switch together, and this connection floats the ground to avoid an earth loop. Paired with the AV 20, it drives 12 of the 13 main channels that processor can handle. Owners with fewer speakers can bridge unused channels for demanding speakers or bi-amp the front pair.

Alternatives

The Marantz AMP 10 is a multichannel power amplifier from the same brand with 16 channels at the same per-channel rating.