Усилители мощности стерео — Musical Fidelity M6S PRX

The M6s PRX is a fully balanced, dual-mono stereo power amplifier from Musical Fidelity's M6s series, released in 2015. Its output stage is derived from the company's Titan power amplifier, and its defining feature is a choke-regulated power supply, a technique taken from classic tube amplifier design and rarely used in transistor amplifiers.

Key specs that matter

The M6s PRX delivers 230W per channel into 8 ohms (24dBW), with an output voltage of 43V before clipping and 140A peak-to-peak current capability. THD plus noise is below 0.007%, signal-to-noise ratio is above 120dB (A-weighted), frequency response is +0/-1dB from 10Hz to 100kHz, and the damping factor is 210. Inputs are two RCA pairs and one XLR balanced pair, switchable, and an RCA loop output passes the signal on. Maximum consumption is 750W, with 0.5W in standby. The chassis measures 440 x 125 x 395mm and weighs 19.7kg, in silver or black.

Engineering and use context

Internally, the two channels are built as independent amplifiers sharing one case, each with its own regulated supply, which avoids interaction between channels under heavy load. The dual-mono, fully complementary bifilar choke regulation system places inductors in the power supply to smooth the rails. This greatly reduces the saw-tooth ripple that capacitor-only supplies leave behind and filters noise arriving from the mains. Musical Fidelity has used this choke regulation approach since 1987, and it is the main technical difference from the Titan and AMS50 amplifiers with which the M6s PRX shares its basic circuit topology. Each channel uses eight output transistors, giving low output impedance and very high peak current delivery. The circuit is designed for low wide-band distortion and large stability margins, so it stays stable into reactive, low-impedance speaker loads. The Class A/B output stage runs cooler than a pure Class A design at this power level.

Pairing

The M6s PRX is designed to partner the matching M6s PRE preamplifier, and its balanced XLR input suits any preamplifier with balanced outputs. The RCA loop output makes bi-amping or even tri-amping straightforward, with one M6s PRX driving each section of the speaker or a second amplifier fed from the first. Its power and current reserve let it drive low-sensitivity and low-impedance loudspeakers that challenge smaller amplifiers.

Alternatives

Musical Fidelity's own M8s PRX is a larger power amplifier in the same design family, for buyers needing more output for demanding loudspeakers.