Phasemation MA-2000 Vacuum Tube Monaural Power Amplifier

300B parallel single-ended class-A monaural tube amplifier with 2A3 transformer-coupled driver stage and Lundahl transformers

The Phasemation MA-2000 is a reference-level monaural power amplifier built around a parallel single-ended 300B output stage, designed to deliver the purity, harmonic richness, and immediacy associated with classic triode designs. Its rigid aluminum chassis, choke-based power supply, and high-grade terminals reflect a commitment to long-term performance and musical refinement.

At its core, the MA-2000 uses an all-triode, non-feedback circuit in a 12AX7 SRPP → 2A3 → 300B topology. A transformer-coupled 2A3 stage drives the parallel 300B output tubes with exceptional stability, while Lundahl interstage and output transformers ensure accurate, wide-bandwidth signal transfer. Independent power transformers for the 2A3 and 300B stages, a 5R4G rectifier tube with choke-filter high-voltage supply, and DC-heated filaments further reduce noise and preserve microdynamic detail. The amplifier’s one-minute startup timer and Furutech input/output terminals round out a design focused on durability and sonic integrity.

The MA-2000 includes both balanced and unbalanced inputs feeding a transformer-type attenuator that maintains signal purity and allows for flexible gain structuring within a system. Separate 4 Ω and 8 Ω output taps provide proper matching for a wide range of loudspeakers, making the MA-2000 a versatile yet uncompromising choice for high-efficiency systems where tone, presence, and emotional immediacy are paramount.

Specifications

Type: 300B parallel single-ended monaural power amplifier

Rated Output: 27 W (THD 5%)

Frequency Response: 10 Hz–40 kHz (+0, -3 dB)

Input Impedance: 47 kΩ

Gain: 27 dB

Residual Noise: 200 μV or less (A-NET)

Output Impedance: 4 Ω, 8 Ω

Power Consumption: 160 W

Accessories: AC power cable

Dimensions (WHD): 10.63" x 9.65" x 17.05" (270 x 245 x 433 mm)

Weight: 44.09 lb. (20 kg)