The FM 711-MKIII is exciting...

FM 711-MKIII power amplifier - drives anything - perfectly
FM 711-MKIII drives anything that is connected - perfectly be able to announce the

"MK-III" version of the FM 711.
The 711-MKIII is a mainstay of FM ACOUSTICS amplifier range.

Originally introduced in 1996 this singular high power amplifier enjoys a constant demand from many different countries. As it can drive anything that it is connected to with perfection, the FM 711-MKIII is here to stay for many many years.


Included in the new MKIII version are all recent developments and ameliorations developed for the FM 1811 and the FM 115.

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.


Massive reserves

Inside the FM 711-MKIII
Inside the FM 711-MKIII


The more massive power supply of the MKIII uses high speed dual rectifiers of very high current capacity.

Superb hand-craftsmanship is evident 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 readily apparent.



Level control

Hand-selected level control
Hand-selected level control

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.







HR modules

New HR modules
New HR modules

The new "HR" modules are used on the inputs. They help to achieve an astounding 100dB (!!!) of rejection of interference, hum, noise etc.

Such signals must be removed before the music signal enters amplification stages. The 711-MKIII is immune against interference.


This rejection is achieved highly selected components and individually fine-tuned discrete Class A circuits guaranteeing the ultimate resolution FM ACOUSTICS products are esteemed for.




High reliability
High reliability

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...).




MKIII Resonance-eliminators

MKIII isolators eliminate resonances
MKIII isolators eliminate resonances


To avoid negative influence from spurious resonance and guarantee positive coupling new resonance-eliminators are employed.

Initially introduced in the MKII series, the new MKIII isolators have improved isolation making the unit immune to parasitic resonances.




With its unique characteristics the FM 711-MKIII will be uncontested for many years to come

  • Music reproduction to dream of
  • Prodigious Power to drive the most demanding loads
  • Proprietary discrete circuitry using special curve-tracer analysed and hand selected semiconductors
  • Superb balanced discrete Class A input stage. Sensors automatically recognize the connection standard and perfectly balance both unbalanced and pseudo-balanced signals sources right at input
  • Tremendous headroom and reserves
  • Perfect signal symmetry
  • Superb rejection of noise, hum or interference thanks to perfectly balanced inputs (interference rejection is 100-1000 times better than other so-called "balanced" equipment)
  • Multi-protection systems for amplifier and speakers trigger the output and reset automatically when the error disappears.
  • No signal compression, limiting nor any other negative influence on the audio signal is possible. The protection circuits are totally separate from all audio stages.
  • Outputs drive any speaker load perfectly, even very low impedance - or high highly capacitive - transducers
  • Unique dynamic damping of speakers results in perfect impulse response and no ringing
  • Proprietary enhanced Class A circuitry provide unmatched musicality
  • Grand Prix-winning circuit technology guarantees total absence of any form of distortion - be it dynamic or static and even at the lowest signal levels - it betters other designs by a magnitude.
  • Precision low noise level controls avoid the often experienced change in tonal characteristics when changing volume level
  • Ultra low-loss FORCEPLUG 200 output connectors.
  • Tremendous output current capability as peak output current is not limited
  • 5000 V mains spike suppressors
  • Mechanical resonance elimination with the new MKIII isolation supports
  • Lowest impedance power supply for unlimited rendering of dynamics
  • The internal transformer is completely shielded from audio circuitry; special shielding techniques prevent stray fields
  • Hand-selected and perfectly matched components of DIN, IEC & MIL standard
  • Each unit is hand crafted and calibrated in Switzerland to absolute performance standards
  • New high reliability components help to further increase lifetime expectancy


Some Specifications


Minimum Power Output:
520 W peak into 8 Ohm
1000 W peak into 4 Ohm
1600 W peak into 2 Ohm


260 W RMS into 8 Ohm
500 W RMS into 4 Ohm
800 W RMS into 2 Ohm


Max. Output Voltage:

140 V pp.


Max. Output Current:
Unlimited repetitive peak output current. No output or DC fuses, absolutely no form of current-, voltage- or any other kind of limiting.


Distortion: 0,005% THD


Bandwidth including Input Filter:
Less than 1 Hz to 60 kHz;
if required, internally setable 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
Minimal unweighted:
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 single ended (unbalanced) sources. Unbalanced sources are automatically balanced right at the input of the FM 711-MKIII.


Input Sensitivity:
1,6 V RMS for full output

Input Impedance:
At all level settings from balanced and unbalanced sources: 40 kOhm

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 unique on- board safeguarding circuits that continuously survey all important parameters.