Усилители мощности стерео — Burmester 909 MK5

The 909 MK5 is a stereo power amplifier from Burmester of Berlin and part of the company's Reference Line. The 909 has been in production since 1990 and has reached its fifth version, and a US listing gives its price as USD 73,495. It is modular, stable into 1 ohm and can be bridged to mono with external adapters or from the factory.

Key specs that matter

In stereo, the 909 MK5 delivers 600 W per channel into 4 ohms, and bridged mono operation gives 1,930 W into 4 ohms. Input impedance is 1.7 kohms on XLR and 5.7 kohms on RCA, input sensitivity is 1.1 V and gain is 36.5 dB. Frequency response runs from below 10 Hz to 220 kHz, signal to noise ratio exceeds 105 dB, THD plus noise is below 0.003%, damping factor exceeds 1,000 into 4 ohms and rise time is 40 V/µs. Connections include XLR input and XLR through, RCA through an adapter, a 10 V trigger and BurSync. The chassis measures 482 x 498 x 482 mm and weighs 72 kg, in black or silver anodised finish.

Engineering and use context

Burmester describes the 909 MK5 as modular, with the amplifier built from separate functional blocks. This low-impedance stability means the output stage and power supply can deliver very high current into loudspeakers whose impedance falls far below the nominal value. A processor supervises the amplifier and carries out fault diagnosis. The XLR through connection passes the input signal on to a second amplifier, which is useful for bi-amping or for chaining a pair of 909s in bridged mono. Like other Burmester amplifiers, the 909 MK5 uses balanced circuitry and Burmester's X-Amp discrete stages, and each unit is assembled in the Berlin factory. The trigger and BurSync connections let a Burmester preamplifier switch it on and off. Bridged, the output is more than three times the stereo figure per channel. The gain is 5 dB higher than that of the 956 MK2, and the rise time compares with 25 V/µs for the smaller amplifier.

Pairing

The 909 MK5 is intended for large, low-impedance loudspeakers that need high current, and its power reserve lets it drive them in large rooms. Balanced XLR connection from a Burmester Reference Line preamplifier suits it best, since the RCA input needs an adapter.

Alternatives

The Burmester 956 MK2 is a smaller stereo power amplifier derived from the 909, weighing 31 kg.