Интегральные усилители — MasterSound Evo 300B

The Evo 300B is a stereo integrated amplifier with valves from MastersounD, the Italian maker from Vicenza that builds single-ended Class A amplifiers with its own output transformers. MastersounD entered the market in 1994 with the 2-11-A, which had a single EL34 per channel, and its range has since included the 300B S.E., the 300B P.S.E. and two 845 Compact models. This one is built around the directly heated 300B triode and runs the output stage in pure triode, parallel single-ended Class A. The amplifier is made in Italy and is supplied to order. The Italian price is EUR 9,755, and the Australian recommended price is AUD 29,999.95.

Key specs that matter

Four 300B power triodes, two per channel wired in parallel, deliver 2 x 24 W. Two ECC802 and two 6SN7 double triodes handle the input and driver stages. On the rear are balanced XLR connections, one line input and one direct input, plus single-ended RCA connections, three line inputs and one direct input. The amplifier is specified for speaker loads of 4 to 8 ohm, and frequency response runs from 8 Hz to 40 kHz at 0 dB. The chassis measures 46 x 41.5 x 27.5 cm and weighs 34 kg. MastersounD supplies a remote handset with the amplifier.

Engineering and use context

MastersounD applies no negative feedback, so the output transformer, wound to the company's own design, has to cover the full passband without a correction loop. Bias for the output valves is automatic but settable, which MastersounD describes as semi-automatic, so owners can check and trim it when valves are replaced. Unlike some other MastersounD integrated models, the Evo 300B has no phono input among its connections. Direct inputs are provided on both the balanced and single-ended sides next to the line inputs.

Pairing

Efficient loudspeakers are the logical partners for a single-ended triode stage of this power. Sources with balanced outputs, such as many DACs and phono stages, can connect through the XLR line input, while up to three single-ended sources share the RCA line inputs. A separate MM or MC phono preamplifier is required for vinyl playback.

Alternatives

The MastersounD Duetrenta is a parallel single-ended integrated using four KT120 valves for 2 x 33 W and adding a built-in MM phono input.