Усилители мощности стерео — Ati (Audio Technologies Inc.) AT2007

Amplifier Technologies Inc., known as ATI, builds the AT2007 as a seven-channel power amplifier, not a stereo unit, built on its Pure Balance topology and aimed at home theater systems where every speaker gets its own identical channel. Its American list price was USD 2,995.

Key specs that matter

ATI rates every one of the seven outputs at 200 W RMS into 8 ohm across 20 Hz to 20 kHz, with all channels driven and with THD and IM distortion held to no more than 0.03 percent at that level. Into 4 ohm the full-band rating climbs to 300 W RMS per channel. Measured at 1 kHz alone, ATI quotes 250 W into 8 ohm and 375 W into 4 ohm. Noise is specified 123 dB down, referenced to full output, and power bandwidth extends from 5 Hz to 100 kHz within +0/-3 dB. The chassis measures 432 mm wide, 178 mm high and 432 mm deep, and weight runs from 23 to 43 kg depending on the model in the series.

Engineering and use context

Pure Balance is a true differential circuit that stays balanced from input to output. Energy is drawn from two large toroidal transformers, rated at 1.6 kVA and 1.04 kVA, which ATI says are 40 percent more efficient than EI types, and each channel has its own separate bifilar winding to lower noise and crosstalk. Reservoir capacitance is 30,000 uF per channel. Protection circuits are optically coupled and reset automatically, while an ultra soft turn-on keeps in-rush current low enough that several units can be switched on together without tripping a breaker. Cooling is by convection alone, so the amplifier runs with no fans. The detachable three-wire power cord is intended for a 15 A circuit, and ATI backs the unit with a seven-year parts and labour warranty.

Pairing

Each channel offers both a balanced XLR input and one of seven unbalanced RCA jacks, so the AT2007 connects to an AV processor or surround preamplifier through either type of lead. Speaker cables attach to seven sets of five-way binding posts. With its high output into low impedances, the amplifier can feed a full 5.1 or 7.1 speaker layout of low-impedance models in a 20 m2 living room or a larger dedicated cinema, leaving the processor to handle decoding and bass management. Since there are no fans, the amplifier can sit in a closed equipment rack in the listening room without adding fan noise, provided there is space for convection airflow around the chassis. ATI also makes the seven-channel AT1827, AT4007 and AT6007.

Alternatives

ATI's AT3307 is another seven-channel amplifier in the range, rated at 330 W per channel.