Power amplifiers mono — AVM Ovation MA 6.3

The Ovation MA 6.3 is a mono power amplifier from AVM Audio Video Manufaktur of Germany, built in the slim Ovation case used by the company's integrated amplifiers. Each chassis drives a single loudspeaker, which means two are required for two channels. Cases come in silver or black aluminium, with a chrome front available as an option, and AVM gives four years of warranty after product registration.

Key specs that matter

Continuous output is 680 W into 8 ohm and 1,000 W into 4 ohm. Inputs are offered as balanced XLR with 14 kOhm impedance and unbalanced RCA with 6.8 kOhm. Frequency response runs from below 5 Hz to 50 kHz. Signal-to-noise ratio is 101 dB(A), distortion stays below 0.1 % at 25 W into 4 ohm, and the damping factor is above 400. Each unit draws up to 1,000 W from the mains, falls below 0.5 W in standby and runs on 120 or 230 V at 50 or 60 Hz. The chassis measures 430 x 130 x 390 mm and weighs 21 kg.

Engineering and use context

Its amplification circuit uses Class A/AB MOS-FET high-current technology in a fully symmetrical, DC-coupled layout. AVM fits 40 MOS-FETs per channel, 20 of them as output devices, and states peak current capability of up to 300 amperes. Power comes from a 1,000 VA toroidal transformer backed by 200,000 microfarads of filter capacitance in each amplifier. Three separate supplies are used, one for the main power stage, one for the processor section and a silent supply reserved for the input circuit. External heat radiators fitted to the aluminium case dissipate the heat of this output stage within the low 130 mm height.

Pairing

Two pairs of speaker terminals allow bi-wiring from each monoblock. Because a menu setting changes input sensitivity, the owner can align the level of both monoblocks with a quiet or a hot preamplifier output, and the balanced input suits most preamplifier outputs. A fully balanced preamplifier connected through XLR keeps the symmetrical signal path of the input stage in use from end to end. The low profile lets both monoblocks stand on ordinary rack shelves beside a matching Ovation preamplifier.

Alternatives

In the same Ovation range, the AVM MA 8.3 monoblock raises output to more than 1,100 W on all loads using two 1,000 VA transformers and 400,000 microfarads of storage per unit.