Усилители мощности моно — Fluo DM125

The DM125 is the entry power amplifier from FLUO, a brand based in Winchester, England, whose name stands for Fast Linear Ultimate Operation. The maker describes it as a dual mono stereo amplifier - two separate circuits for left and right share one chassis, and each channel draws on its own capacitors, rectifiers and mains transformer windings. FLUO works as a collective of specialists under the creative direction of Keith Martin, who founded the power conditioning brand IsoTek in 1999.

Key specs that matter

Rated output per channel is 125 W into 8 ohms and 250 W into 4 ohms, rising to 500 W into 2 ohms on a short-term basis. All figures refer to resistive loads and 230 V AC mains. At idle the amplifier draws 70 W from the wall. A 6.3 A slow-blow fuse caps long-term consumption at 1,450 W per channel, so a continuous sine tone into 2 ohms yields less than the short-term figure. The balanced XLR input presents 40 kOhm and the RCA input 20 kOhm. The case measures 485 mm wide, 270 mm high and 535 mm deep.

Engineering and use context

The purpose of the split supply is simple - when a heavy bass demand pulls down the voltage on one channel's capacitors, the other channel's reservoir is unaffected, which FLUO contrasts with a conventional stereo amplifier where both sides share the same capacitors and the same sag. The output stage uses a single-die MOSFET per channel rather than a bank of paralleled transistors, and the design is meant to double its output each time the load impedance halves. The signal goes straight to the speaker terminals without the series coil that many amplifiers fit for protection. Instead, a monitoring circuit watches for abnormal high frequencies, voltage, current, phase angle and load. When it detects a fault, such as a frayed speaker wire causing a short, it mutes the input for 1 second, then checks for 1 ms whether the fault is still present and resumes playback once it has gone. The amplifier also mutes if it runs too hot. The heat sink fins, top and front panel are shaped to scatter reflections up to beyond 20 kHz.

Pairing

The protection system will not accept speaker loads below 1.5 ohms, so any speaker whose impedance stays above that floor is within its range. FLUO advises shielded signal cables because strong external fields can raise the noise level. Its own PRE1 dual mono preamplifier is described as a balanced match and uses the same JFET balanced input circuit.

Alternatives

The FLUO DM250 uses the same dual mono layout in the same case size with twice the rated output and a separate mains transformer and power cord for each channel.