Power amplifiers stereo — Eversolo AMP-F10

Eversolo's AMP-F10 is a stereo power amplifier working in Class AB with Class A bias. Eversolo intends it for use with its DMP-A8 and DMP-A10 network players, which supply the volume control. The list price is USD 2,480 in the United States and EUR 2,580 in Germany.

Key specs that matter

In stereo the rating is 200 W RMS per channel into 8 ohm, 320 W RMS into 4 ohm and 450 W RMS into 2 ohm. Bridging the channels yields 650 W RMS into 8 ohm and 950 W RMS into 4 ohm. THD+N is 0.008% at 1 kHz, and noise sits 113 dB below the signal, A-weighted. Crosstalk measures -95 dB at 200 W into 8 ohm, while damping factor exceeds 600 at 8 ohm and 1 kHz. Response extends from 10 Hz to 30 kHz within plus or minus 0.5 dB at 1 W into 8 ohm. With its feet, the case is 430 mm wide, 147 mm high and 310 mm deep, and it weighs 18 kg.

Engineering and use context

At low and moderate output the stage works in Class A, shifting to Class AB as demand grows. Five pairs of precision-matched high-current MOSFETs are wired in parallel on each channel so that current spreads evenly across the devices. A 1000 W linear supply with independent sections for left and right gives each channel its own current reserve and keeps the two sides from interfering. Between the mains input and the audio circuits, a DC filter removes low-frequency DC components, which also reduces hum from the toroidal transformer. The input stages are dual differential amplifiers in a symmetrical circuit with negative feedback, which Eversolo uses to suppress common-mode noise. The front carries two backlit analogue VU meters. Mains operation is 110 to 120 V at 60 Hz or 220 to 240 V at 50 Hz, and maximum consumption is 1,200 W. The box also holds a mains cord and a trigger lead.

Pairing

The rear offers XLR and RCA inputs, one stereo pair of each, both with an impedance of 10 kOhm. A gain switch selects 23 dB or 29 dB. At the lower setting, full output needs 5.2 V on XLR or 2.65 V on RCA, and at the higher setting 2.4 V on XLR or 1.3 V on RCA, so the 29 dB position suits sources and preamplifiers with modest output levels. The 2 ohm rating makes the amplifier usable with difficult low-impedance speakers, and a second unit allows bridged mono operation for one channel each.

Alternatives

The Eversolo AMP-F8 is a smaller stereo power amplifier of the same Class AB type, with three pairs of MOSFETs per channel and an 800 W linear supply.