It is with great joy that FM ACOUSTICS announces the "MK-II" version of the FM 411. The original winner of the coveted
"Component Of The Year" award,
the FM 411 was somewhat expected to find admirers but who would have thought that it would stay such a success over its 12 years of continuous production?
Perfected so carefully that it never required a single modification or correction in all these years, it is FM ACOUSTICS most successful power amplifier - not least because it provides an unmatched price/performance ratio.
Recently, new parts have become available that - together with advanced insights from continuous research - allow the first amelioration since 1994.
With such a background, the refinements can, of course, not be "tremendous". They result in some smaller refinements but also some more substantial improvements - as described below.
Superb hand-craftsmanship even where it is not visible (here a detail of the underside of the internal chassis). The quality of each hand-pressed connector is carefully inspected before assembly. The outstanding standard of hand-soldering (important for long-term reliability) is apparent.
The more massive power supply of the MKII is helped by cooled dual rectifiers featuring high speed at the same time as very high current capacity.
New sealed long-life level controls use a conductive plastic track rather than the usual carbon or cermet track. In addition to much longer life expectancy this provides better resolution and guarantees no noise.
The new "HR" modules are used on the inputs. They help to achieve an astounding 100dB (!!!) of rejection of Common Mode signals (such as interference, hum, noise etc. which must be cancelled out before the amplification stages). They rend the FM 411-MKII immune against interference. This CMRR rejection is achieved not with cheap op amps but with individually fine-tuned discrete Class A circuits guaranteeing the ultimate resolution FM ACOUSTICS products are esteemed for.
Light bulb changes are a thing of the past.
FM ACOUSTICS' new frontpanel display provides a more even light distribution and uses high reliability LED's instead of incandescent light bulbs.
These LED's have a theoretical lifetime in excess of 100'000 hours (we could not really test them for that long so let's hope the specifications are realistic...).
Another small detail: left the new ultra-bright bulb now used for the mains power switch illumination. The cost is 3000% higher than the good old "long life" light bulb on the right (which needs replacement after a while - depending on quality of mains power). The new lamp uses dozens of LED's encased in its housing achieving higher brightness and much longer lifetime.
It is compatible and can also be used in the MKI version of the amplifier upon request (although not free of charge - for the above reason).
To avoid negative influence from spurious resonance and guarantee positive coupling the 411-MKII employs FM ACOUSTICS unique resonance-eliminator supports. These isolate the unit from potential resonances making the unit immune to parasitic resonances.
Minimum Power Output:
320 W peak into 8 Ohms
600 W peak into 4 Ohms
1000 W peak into 2 Ohms
160 W RMS into 8 Ohms
300 W RMS into 4 Ohms
500 W RMS into 2 Ohms
Max. Output Voltage: 110 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: 0,005% THD
Bandwidth including Input Filter:
Less than 1 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: 3 us
Hum and Noise:
Below full power typically -110dB
better than -100 dB
Proprietary electronically balanced discrete enhanced class A circuitry, 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.
1,6 V RMS for full output
At all level settings from balanced and unbalanced sources: 40 kOhms
Input Stage Common Mode Rejection:
100 dB typically, better than 90 dB at 50 Hz, even better at other frequencies.
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.