Усилители мощности стерео — Audia Flight STRUMENTO n° 4

The Strumento n°4 comes from the Italian maker Audia Flight as a stereo power amplifier, built in a single tall chassis of 450 x 280 x 500 mm. It has been sold in a Standard version and a higher-output Signature version, and a later mk2 revision is offered in black or silver. The mk2 is priced at AUD 49,990 in Australia.

Key specs that matter

In Standard form each channel is rated at 250 W RMS into 8 ohm, 500 W into 4 ohm and 900 W into 2 ohm, while the Signature version lists 300, 600 and 1,000 W into the same loads. Voltage gain is 29 dB, which puts the input sensitivity for full output at 1.41 V RMS. Input impedance is 7.5 kOhm on both the balanced and the unbalanced connections. Bandwidth at 1 W and -3 dB runs from 0.3 Hz to 1 MHz, and the slew rate into 8 ohm is given as 200 V per microsecond or higher. Quoted distortion is 0.05 %, the signal to noise ratio is 110 dB and the damping factor into 8 ohm reaches 1,000. Mass is stated as 90 kg in one specification sheet and 95 kg for the mk2.

Engineering and use context

Audia Flight keeps every stage of the circuit balanced. For the output stage Audia Flight fits a custom 3,000 VA audio transformer, while two 150 VA toroidal transformers feed the preceding stages and a separate 15 VA toroid runs the logic control and protection circuits. The main supply bank combines twenty-eight 10,000 uF 40 V capacitors of extra-low impedance, for a total of 280,000 uF. Instead of fuses in the signal-carrying supply, a microprocessor reads a current sensor, watches the load and triggers protection. Idle consumption without signal is about 400 W, rising to 1,000 W when both channels deliver 260 W RMS into 8 ohm, and standby draw falls below 1 W. Maximum draw in one specification is 3,300 W. The mains section can be set for 100, 110-115, 220-230 or 240 V, which lets the same model ship to different regions.

Pairing

Because the balanced and unbalanced inputs share the same input impedance, a preamplifier with a low output impedance is the sensible partner, and a balanced link keeps both legs of the fully differential circuit in use. The power rise into low loads makes the amplifier suited to low-impedance loudspeakers, and the tall, heavy chassis calls for a floor position or an amplifier stand rated for the load.

Alternatives

Audia Flight's FLS4 sits in the FLS range as a stereo amplifier of lower output, rated at 200 W into 8 ohm, 380 W into 4 ohm and 700 W into 2 ohm.