Pioneer A-605R Amplifier

At first sight the model Pioneer A-605R by functional abilities resembles its famous precursor - the A-400 amplifier or more modern model A-300R with minimal number of controls. On the big front panel, that is slightly curved, in the center a large handle of motorized volume control, and button of main switch and inputs selector are visible on the panel sides, each with its own indication. But behind a flip cover that is so rarely met of amplifiers the quite good functional equipment is hidden. The amplifier has all traditional controls, including a tone-compensation, reducing of volume by -20 dB, record selector and its monitoring, "DIRECT" regime. Turning on of the most part of modes has a visible indication that is usually set in the mode selection button. For instant, in the normal state the indicator in the handle of volume control has an even glow, but when the "MUTING" mode is turned on together with volume decreasing this indicator begins to flash with a frequency of 1 Hz, thus visually displaying this mode. Connectors on the back panel do not have any special features. As in the other devices, in the A-605R connection of six signal sources is possible, including a turntable with an MM type head. One can connect two pairs of acoustic systems with heavy screw clips. There is a bus of remote control and mains connectors - three for additional units connecting and one for connecting of the amplifier to a mains. And remote control completes this functional equipment; it controls both multiple functions of the whole complex and the amplifier too, carrying out its turning on, volume control and signal source selection. But the main feature of the amplifier is using of powerful transistors MOSFET (IRF540 and IRF9540 with n- and p-channels, respectively) in an output stage, that gives sounding softness and power. Modern idea of symmetry of two channels with using of two separate radiators is applied in the construction. As is known, it gives the amplifier's work more stability of characteristics and coincidence of channels parameters. A power supply is designed using a toroidal transformer, and filter capacitors are ones of the largest among tested models (15000 uF/50V), that naturally has a wholesome effect on music pulses playback. Besides, as the company affirms, together with rational design of radiators and special circuitry in the control circuit a microprocessor is used, that allows saving energy more efficiently. Result is impressive - by the weight of amplifier of just 6.6 kg (14,5 lbs), its both channels gather persistent power 126 each (when 120 W are declared). By power decreasing to 122 W distortions are sharply reduced up to 0.1 %. And by follow-up power decreasing distortions decrease significantly lower than declared 0.05%. Parameters reserve is just wonderful. All this ensures the device lifelike and powerful sounding rich till velvety tangibility of bass. True, by very clear and detailed playback of the whole frequency range, appreciable excess by low frequencies places the device in the category of emotional performers of music of modern forms. Jazz baritonal solo or contrabass - just cool! Pioneer gives very character and comfortable sounding, but it is for lover.