Интегральные усилители — MasterSound Compact 300B

The MasterSound Compact 300B is a tube integrated from Italy that operates in single-ended class A, with one 300B directly heated triode per channel in the output stage and 0 dB of negative feedback. MasterSound rates it at 11 W per channel.

Key specs that matter

The tube complement is a selected pair of 300B output triodes, two ECC802 as pre-drivers and two 6SN7 as drivers. Connections are split between XLR and RCA, with one line and one direct input on XLR and three line plus one direct input on RCA, all at 50 kohm input impedance. Line input sensitivity is 1000 mV. Bandwidth is quoted as 8 Hz to 40 kHz at 0 dB, and the speaker terminals accept 4 or 8 ohm loads. Power consumption is 136 W. The amplifier measures 450 x 430 x 270 mm and weighs 33 kg.

Engineering and use context

The output transformers are MasterSound's own design, wound by hand at the Italian factory run by the Sanavio family. Bias is automatic but settable, with a bias control on the rear panel. The rear panel carries six speaker terminals, two black ones for the higher-impedance taps and four red ones for the lower-impedance taps, and an impedance selector and a mains voltage selector that are set for the destination country and speaker load before delivery. A red LED on the chassis lights once the amplifier has reached operating temperature. The circuit board uses 24 carat gold connections, a fuse holder is built into the mains inlet, and a handset for remote operation comes in the box. The maker's warranty runs five years and excludes the tubes.

Pairing

With a low power rating from its single-ended triode stage, the Compact 300B is meant for efficient loudspeakers with a stable impedance, connected to the tap that matches their nominal impedance. The direct inputs, offered on both XLR and RCA, let an external preamplifier use the Compact 300B as a stereo power amplifier, so it can be integrated into a system that already has a separate control unit. The remaining line inputs serve digital converters, network players, tuners or an outboard phono preamplifier, and the balanced line input suits sources with XLR outputs when the source sits some distance away from the amplifier rack.

Alternatives

Within the same maker's integrated amplifier catalogue, the Dueundici is a single-ended class A model using two EL34 tubes for 2 x 11 W in triode mode.