MastersounD Evolution 845

MastersounD Evolution 845 – four 845 valves in a pure triode dual mono Class A integrated amplifier

The flagship of the MastersounD range

The MastersounD Evolution 845 is the top model in the MastersounD lineup. Four 845 output valves work in a parallel single-ended dual mono circuit in pure Class A. Consequently, it delivers 2× 55 W with zero negative feedback — the highest output MastersounD offers in a single-ended topology. Since each channel has its own separate power supply, crosstalk is therefore reduced to an absolute minimum.

Dual mono — complete channel separation

In a dual mono design, left and right channels operate entirely independently. As a result, there is no interaction between channels — the stereo image is thereby as precise and stable as the circuit allows. Furthermore, the Evolution 845 uses a PCB with gold tracks, which optimises signal transfer throughout. The hand-wound bespoke MastersounD output transformers are moreover designed specifically for four 845 valves per stereo pair.

Connectivity and automatic bias

Inputs cover one balanced XLR line input and one direct XLR input, plus three single-ended RCA line inputs and one direct RCA input. Since the direct inputs bypass the preamplifier stage, the Evolution 845 consequently works as a pure power amplifier with an external preamplifier. Automatic bias keeps all four 845 valves at their optimal operating point. No manual adjustment is therefore needed during normal use.

Italian craftsmanship at the highest level

Above all, every Evolution 845 is individually assembled and run in for 48 hours at the Arcugnano factory before leaving. The chassis combines steel with Italian walnut veneer — built to last. MastersounD backs it with a five-year warranty. Those seeking an entry point into the 845 sound can consider the Compact 845, which delivers 2× 30 W with the same valve philosophy.

Specifications

• Type: pure triode parallel single-ended dual mono Class A integrated amplifier
• Output power: 2× 55 W Class A
• Valves: 4× 845, 2× ECC802, 2× 6SN7
• Inputs XLR: 1× line + 1× direct
• Inputs RCA: 3× line + 1× direct
• Input impedance: 50 kΩ
• Bandwidth: 8 Hz–50 kHz, 0 dB
• Output transformer: bespoke MastersounD, hand-wound
• Bias: automatic
• Load impedance: 4–8 ohm
• Negative feedback: 0 dB
• Remote control: included
• Warranty: 5 years (valves 1 year)
• Dimensions: 560×495×280 mm
• Weight: 53 kg
• Origin: hand-built in Italy

Frequently asked questions about the MastersounD Evolution 845

What is the difference between the Evolution 845 and the Compact 845?

The Evolution 845 uses four 845 valves in a dual mono circuit, consequently delivering 2× 55 W — nearly double the Compact 845's 2× 30 W. Furthermore, the dual mono construction provides fully separate signal paths per channel, thereby improving stereo imaging.

What does dual mono mean in the Evolution 845?

Left and right channels each have their own separate power supply and amplifier circuit. Since there is no shared circuitry between channels, crosstalk is eliminated — the stereo image is therefore more precise and stable than in a conventional stereo design.

Which loudspeakers suit the Evolution 845?

With 2× 55 W Class A, the Evolution 845 suits a wide range of loudspeakers. Speakers of 87 dB sensitivity or above with a stable impedance give the best results. Since output is considerably higher than the Compact 845 or EVO 300B, it is moreover compatible with less sensitive designs.