The FX is proof that in audio, as in life, it is not about how much you have, but how well you use the little you need. It is the unassuming titan: a black box that holds a masterclass in restraint.
Because of the low-feedback, high-bandwidth design, the FX handles leading-edge transients—the strike of a piano hammer, the snap of a snare drum—with startling realism. There is no smearing. But the real magic is in the micro-dynamics. At low volume, late at night, the FX retrieves the subtle decay of a cymbal or the breath of a saxophonist with a delicacy that 200-watt behemoths often crush under their own authority.
The FX is, in fact, a "Class A" amplifier for the first critical 10 to 15 watts. Only when pushed harder does it slide gracefully into Class B. This is not a marketing gimmick; it is a sonic philosophy. By keeping the output devices constantly biased “on,” the FX eliminates crossover distortion—the tiny notch of discontinuity that occurs when transistors switch on and off. This grants the amplifier an almost tube-like liquidity in the midrange, but with the grip and speed of solid-state. Open the lid of an FX, and a minimalist gasps with joy; a maximalist weeps. Where other amplifiers looked like circuit boards suffering from acne—covered in capacitors, relays, and protection circuits—the FX is spartan. Its signal path is vanishingly short.
In the high-fidelity industry, there is an unspoken hierarchy of glamour. Turntables have the romance of mechanical precision; tube amplifiers glow with nostalgic warmth; and loudspeakers, with their exotic drivers and wooden veneers, are the furniture of dreams. The power amplifier, by contrast, is often treated as the mule of the system—ugly, utilitarian, and expected only to deliver current without complaint.
Modern Class D amplifiers now boast 90% efficiency and 0.0001% distortion, yet many listeners still hunt for the FX. Why? Because the FX reminds us that high fidelity is not a number. It is the illusion of a live performance. By sacrificing power for purity, and features for focus, Musical Fidelity created an amplifier that does not just reproduce music—it understands the importance of the first watt.
On paper, this was a failure. In practice, it was a liberation. Michaelson understood a dirty secret of the audio industry: high global negative feedback, the tool most engineers used to achieve high wattage with low distortion, was the enemy of transient response and harmonic integrity. The FX was designed around a different principle: