Усилители мощности стерео — Anthem STR Power Amplifier

Anthem's STR Power Amplifier is a stereo Class AB design, designed, engineered and made in Canada. It follows a true dual-mono layout, in which the left and right sides draw on separate toroidal transformers, and its US price was set at USD 5,999. Anthem lists black and silver versions, and a 7-inch graphic display sits behind the front glass for status readouts.

Key specs that matter

Anthem rates the STR, both channels driven, at 400 W per channel into 8 ohm, 600 W into 4 ohm and 800 W into 2 ohm. Voltage gain is 29 dB. Input impedance is 10 kOhm on RCA and 15 kOhm on XLR. Signal to noise ratio is 121 dB, A-weighted and referenced to 400 W. At 400 W, THD is 0.0007 percent at 1 kHz and 0.004 percent at 20 kHz. The casework is 171 mm high, 432 mm wide and 470 mm deep, and the amplifier weighs 27 kg.

Engineering and use context

The two transformers are rated at 600 VA each, and each channel has 32,800 uF of filter capacitance. Sixteen bipolar output devices per channel drive the speaker terminals, and the output stage connects straight to the capacitor bank with no rail fuses in between. The input topology uses eight low-noise bipolar devices in a cascoded complementary feedback stage with active loads, which Anthem says lowers distortion and extends bandwidth, and transistors in critical stages are hand-selected and matched. Keeping the channels on separate supplies is intended to hold channel separation and keep one channel from interfering with the other. An ALM protection system tracks voltage, current and heat sink temperature, and a sequence-controlled soft start limits inrush current when the unit powers up. The connectors are high-conductivity types chosen for audiophile use, and the power supply is linear rather than switch-mode. Anthem gives a 5-year warranty on separate power amplifiers in Canada and the USA.

Pairing

The STR Power Amplifier was launched alongside the STR Preamplifier, and the two were built as a matching set. Power management can follow a trigger signal from the preamp or wake the amplifier when an audio signal appears at its inputs, and each channel accepts either an unbalanced RCA or a balanced XLR source. The rating into the lowest impedance shows that difficult loads are within its design brief.

Alternatives

The Anthem Statement P2 is a stereo power amplifier from Anthem's Statement line.