Усилители мощности моно — Western Electric 97A

The 97A is a pair of valve mono power amplifiers from Western Electric, built at the company's plant in Rossville, Georgia, alongside the 300B triodes it uses. Each chassis runs eight of those tubes, and the company's current amplifier catalogue lists the 97A next to the 91E integrated and the 116-C phono preamplifier. The Rossville Works facility was established in 2018. The price is USD 124,999 per pair, and the maker covers parts and labour for three years.

Key specs that matter

Each monoblock is rated at 80 W RMS, with output connections for 4 ohm and 8 ohm loads. Frequency response is held within 1 dB from 10 Hz to 100 kHz. Total harmonic distortion stays under 0.05% at 10 W, under 0.15% at 50 W and under 0.9% at full power, and noise sits 100 dB below the 80 W rating. The damping factor is 16. Input impedance is 500 kOhm on both input types. Each unit draws 400 W true RMS from the mains, measures 435 mm wide, 825 mm deep and 275 mm high, and weighs about 74.8 kg.

Engineering and use context

The valve line-up per channel is eight Western Electric 300B output triodes, three 6SN7GTB and one 6SL7 in the earlier stages. Western Electric first produced the 300B in 1938 for projection rooms in Hollywood sound systems, and in the 1930s the tube went into the wall-mounted Type 500A and Type 91A amplifier sets of the Wide Range and Mirrophonic cinema sound systems. The company says current tubes still follow the original 1938 specification, and the Rossville factory was purpose-built to handle the many separate steps of tube making. Production at Rossville combines turbomolecular vacuum pumping, computer-controlled machinery and cleanroom practice with tooling dating back as far as 1943, and filament core material comes from a 1963 melt made at the old Hawthorne Works in Chicago. Inside the 97A, the circuit is wired point to point with MIL-W-16878 stranded silver-plated copper wire insulated in PTFE. The front panel carries a power selector and an LED power meter that shows low, medium and high output.

Pairing

Both single-ended RCA and balanced XLR inputs are fitted, with a toggle switch choosing between them, so a preamplifier with either output type can be connected, provided it delivers the 0.50 V that the 97A needs for full power. Loudspeakers connect to the output tap that suits their rated load.

Alternatives

Western Electric builds no other mono power amplifier, and the 97A is its only standalone power amplifier of any kind.