The FM 711-MKIII - pure excitment...

FM 711-MKIII power amplifier - drives anything - perfectly
FM 711-MKIII drives anything that is connected - perfectly

 

The 711-MKIII is a mainstay of FM ACOUSTICS amplifier range.

Originally introduced in 1996 this singular high power amplifier enjoys constant demand. As it can drive anything that it is connected to it with absolute perfection, the FM 711-MKIII is loved worldwide and already a modern Classic.

 

 

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

As new parts and technologies became available they were included in the MKIII and result in a few smaller refinements but also some substantial performance increase.

 

 

Massive reserves

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

 

The more massive power supply of the MKIII uses multiple high speed rectifiers strategically placed.

 

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 visually and electronically before assembly.

 

 

The outstanding standard of hand-soldering (important for long-term reliability) is readily apparent.

Hand positioning and hand-soldering is 30-120 times more expensive than automatic wave soldering but there is no comparison in long term reliability. This may only be realized in 5 to 15 years time, but is one of the reasons an FM ACOUSTICS keeps its value.

 

 

Selected level controls

FM ACOUSTICS Hand-selected level controlS
Hand-selected level controls

 

Sealed long-life level controls use a conductive plastic track rather than the usual carbon or cermet track. Unique grounding is used to achieve lowest noise floor.

 

In addition to much longer life expectancy this provides finer resolution and prevents interference.

 

As in the FM ACOUSTICS tradition every component is measured, tested and anything that is not perfect is rejected. Long term stability guarantees freedom of noise,, interference and lasting performance. 

 

 

 

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.

 

Any such disturbance must removed before the music signal enters the amplification stages. The 711-MKIII is literally 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.

 

 

Display

High reliability everywhere
High reliability display

 

A small feature - but with an nice long term effect:

Light bulb changes are a thing of the past.

 

FM ACOUSTICS' new front panel display provides a more even light distribution and uses high reliability LED's instead of incandescent light bulbs.

 

These quality 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, 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 phenomenal impulse response accuracy 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 the 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;
 

Risetime at Full Power: 3 us

 

Hum and Noise:
Below full power typically -110dB
Minimal unweighted:
better than -100 dB

 

Input:
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

 

Chassis Resonance Damping:
New chassis design effectively isolates sensitive electronic and mechanical components from potential negative influences such as induced resonances. Specific purpose-designed anti-resonance technology is employed.

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.