FM 411

For 11 years uninterupted (!!!) the most successful power amplifier: the FM 411
For 11 years uninterupted (!!!) the most successful power amplifier: the FM 411


Minimum Power Output:
Per channel, both channels operating
300 W peak into 8 Ohms
550 W peak into 4 Ohms
900 W peak into 2 Ohms

275 W RMS into 4 Ohms
450 W RMS into 2 Ohms

Max. Output Voltage: 100 V pp.

Max. Output Current:
Unlimited repetitive peak output current.
More than 20 A continuous per channel.
No output or DC fuses, absolutely no form of current-, voltage- or any other kind of limiting.

Distortion: Average distortion: 0,006% THD

Bandwidth including Input Filter:
Less than 3 Hz to 60 kHz;
if required, internally settable to any frequency between 1 kHz and 60 kHz (Low-Pass) and
1 Hz to 1 kHz (High-Pass).


Risetime at Full Power -3dB: 3 us
Gain: 29 dB


Hum and Noise:
Below full power typically better than -110dB

Minimal unweighted:

better than -100 dB

Proprietary electronically balanced discrete enhanced class A circuitry, non-polarized, floating ground, non- inverting or inverting mode. Optimal performance with either balanced or unbalanced (single-ended) sources. Unbalanced sources are automatically balanced right at the input of the FM 411.


Input Sensitivity:
1,6 V RMS for full output
Input Impedance:
At all level settings from balanced and unbalanced sources: 40 kOhms

Input Stage Common Mode Rejection:
90 dB typically, better than 80 dB at 50 Hz, even better at other frequencies.

Load Impedance:
No minimum impedance. The amplifier is designed for 1 Ohm to 10'000 Ohm systems. It can drive any speaker impedance (even below 1 Ohm) with dynamic (music) signals without any limiting, compression or other negative effects on the audio signal. Despite this, the amplifier is fully protected against short circuits, open circuits and all other adverse conditions via a unique onboard computer that continuously surveys all important parameters.