Усилители мощности моно — McIntosh MC611

The MC611 is a monoblock solid-state McIntosh amplifier intended for stereo pairs or for home theater channels. It replaced the previous McIntosh monoblock of the same rating and, compared with it, doubles the filter capacitance, raising dynamic headroom from 1.8 dB to 2.8 dB, which McIntosh describes as a 55% gain. The front now uses direct LED backlighting, and the power and audio transformers sit in glass-topped enclosures.

Key specs that matter

Rated power is 600 W into 2, 4 or 8 ohm, with separate binding posts for each impedance. Total harmonic distortion stays at 0.005% maximum from 250 mW to full power across 20 Hz to 20 kHz, and intermodulation distortion is also 0.005%. Response is +0, -0.25 dB from 20 Hz to 20 kHz and +0, -3 dB from 10 Hz to 100 kHz. Signal-to-noise, A-weighted, is 124 dB balanced and 120 dB unbalanced, and the wideband damping factor exceeds 40. Input sensitivity for full output is 4.8 V balanced or 2.4 V unbalanced at 22 kohm, and voltage gain is 29 dB on the 8 ohm tap, 26 dB on 4 ohm and 23 dB on 2 ohm. The chassis measures 44.45 x 23.97 x 55.88 cm and weighs 44.32 kg.

Engineering and use context

The circuit is Quad Balanced - two matched amplifiers working in push-pull, their outputs combined in a McIntosh Autoformer, so the design is balanced from input to output. The Autoformer also matches the output stage to each speaker tap and blocks DC from reaching the speaker. Output transistors are of the ThermalTrak type, and the audio Autoformer and power transformer are placed behind the front panel with two Monogrammed Heatsinks behind them. Power Guard keeps distortion under 2% even with a 14 dB overdrive signal, while Sentry Monitor protects the output stage without fuses and thermal circuits mute the unit if it overheats. The 203 mm blue watt meter is peak responding and has a peak hold mode. The rear binding posts are spaced further apart than on the predecessor. The amplifier is factory set for one mains voltage between 100 and 240 V, drawing 6.6 A at 120 V and under 0.5 W in standby, and it switches itself off when idle.

Pairing

A pair suits a preamplifier with balanced outputs, since the XLR input gives the lowest noise figure. Low-sensitivity speakers and very low impedance loads are within range, because the matching tap delivers the full rating. The 12 V power control connections switch the monoblocks with a McIntosh preamplifier.

Alternatives

The McIntosh MC1.25KW is a larger one-channel solid-state model rated at 1,200 W.