Усилители мощности моно — Karan Acoustics POWERb STEREO

The POWERb STEREO counts as the two-channel amplifier of the Master Collection of Karan Acoustics, the Serbian electronics maker led by Milan Karan. It shares its casework and mass with the POWERb MONO, but puts two channels into that enclosure instead of one, and Karan guarantees parts and labour on it for five years. Karan fits every Master Collection product with Critical Mass Systems CS2 isolation feet.

Key specs that matter

Karan specifies 450 W per channel into 8 ohm, 800 W into 4 ohm and 1,350 W into 2 ohm, with a peak output of 600 W into 8 ohm. Gain is 30 dB, and an input of 2.0 V RMS takes the amplifier to its maximum output. The rear carries two XLR and two RCA sockets, each input loading the source with 30 kOhm. Karan lists response as 20 Hz to 20 kHz with no deviation, extending from DC to 300 kHz at the minus 3 dB points. Both THD and IMD are quoted at 0.03%, and signal to noise exceeds 120 dB unweighted. Rise and settling time stays below 450 ns, while the amplification stages manage a slew rate of 1,500 V per microsecond. The unit measures 504 x 292 x 521 mm and weighs 81 kg.

Engineering and use context

Karan equips it with two low noise toroidal transformers of 1,500 VA each, feeding a custom made capacitor bank of 180,000 uF. The mains transformers in this model are smaller than the 2,100 VA pair used in the monoblock, which is where the two versions part ways inside, while the reservoir capacitance is identical. The amplifier runs on a nominal line voltage of 115 V or 230 V and accepts a deviation of 10% in either direction from that value. The gain is 6 dB lower than that of the monoblock. The rating into the lowest load shows that the output stage is specified for very low speaker loads.

Pairing

A single chassis serves a stereo pair of loudspeakers, which saves floor space and one mains circuit compared with a pair of monoblocks, and keeps the cabling between preamplifier and amplifier to one location. The balanced inputs suit Karan's Master Collection LINEa and LINEb preamplifiers, whose casework shares the 504 mm width. Given its weight, the amplifier needs a floor position or a rack shelf rated for the load.

Alternatives

The POWERa Stereo is the higher Master Collection stereo amplifier, rated at 650 W per channel and built as a dual mono design.