Усилители мощности стерео — Msb Technology The S500 Stereo Amplifier

The S500 is the larger stereo power amplifier from MSB Technology, the California maker of ladder DACs, and sits above the S202 in the range. Against the S202, it more than doubles the output into both loads, triples the static consumption and offers a higher maximum gain. It pairs a zero-feedback Class A matched impedance input stage with discrete high-current output buffers and a 1.0 Farad power core.

Key specs that matter

MSB rates continuous output at 500 W per channel into 8 ohm and 900 W into 4 ohm, at under 1 percent distortion. Three gain settings are offered, measured from a 75 ohm source - 16.2 dB low, 22.2 dB medium and 28.2 dB high. Frequency response stays within 0.025 dB across 20 Hz to 20 kHz. Signal to noise is above 136 dB, or 140 dBA, crosstalk at 2 kHz is under -110 dB, equivalent input noise is 0.5 microvolt and output impedance is 0.07 ohm. Two XLR inputs accept a selectable input impedance of 75, 300 or 1,200 ohm. Static consumption is 270 W. MSB lists the chassis at 381 mm wide, 599 mm deep and 305 mm high, with a weight of 74 kg.

Engineering and use context

Custom low-noise high-current toroidal transformers feed the power core, and the amplifier takes mains through a 20 A IEC connector protected by a 15 A slow-blow fuse. Mains input is auto-switching between 120 and 240 V, and a fixed 100 V build exists. The heatsink is machined from a 23 kg block of aluminium down to 7.9 kg, and each amplifier offers about 6.5 m2 of cooling surface. The gain switch lets the owner match the level to speaker sensitivity so the preamplifier volume works in a useful range. Other controls are on and off, standby, a display dimmer and a 12V mode switch, with two MSB trigger ports. Each channel has a single binding post set, and multiple ground posts help reduce interference. MSB describes the speaker terminals as intuitive lugs designed for easy connection. The finish is matte silver or matte black anodising.

Pairing

The high output into low loads makes the S500 a candidate for demanding low-impedance loudspeakers of low sensitivity, while the low gain setting keeps noise down with very sensitive designs. Any balanced line source with a volume control, such as an MSB DAC with its passive attenuator, connects through the XLR inputs, and the trigger ports let it switch on with the rest of an MSB system.

Alternatives

The MSB S202 Stereo Amplifier is the compact two-channel model, built on a single transformer in a smaller billet case.