The MB81 PP are powerful top-tier power monoblocks — „Goliaths” of 250 W per channel, created to drive modern, demanding loudspeakers in large rooms. They operate in pure Class A, fully triode, on 1950s Russian GU81 transmitting valves, prized for their excellent sonic qualities and enormous durability.
The result is a seemingly unlimited scale and control, combined with a fluid, three-dimensional soundstage of warm, natural timbres. The input stage is based on a 6SL7 valve and two 6SN7s, and the driver uses EL34 valves in triode mode.
Each monoblock is entirely hand-assembled, point-to-point, with no printed circuit boards — which makes service and modification easier (including optional Mundorf silver/gold capacitors). It is a design for the audiophile who makes no compromises on power or quality.
| Output power | 250 W (8 Ω, 1 kHz, 2% THD) |
| Output valves | 2× GU81 |
| Driver valves | 1× 6SL7 + 2× 6SN7 + 2× EL34 |
| Operating mode | pure Class A, triode |
| THD distortion | 0.1% (8 W) / 0.5% (100 W) |
| Signal-to-noise ratio | −100 dB |
| Damping factor | 3 |
| Frequency response | 12 Hz – 28 kHz (−1 dB at 8 V) |
| Input impedance | 47 kΩ |
| Speaker impedance | 4 – 16 Ω |
| Sensitivity | 0.65 V (0 dB FB) / 1 V / 2.7 V |
| Power supply | 220 / 240 / 115 V; 450 W typical (max. 750 W) |
| Dimensions (W × D × H) | 450 × 660 × 385 mm (400 mm with cage) |
| Weight | 50 kg (each monoblock) |
Powerful valve power monoblocks on GU81 valves — 250 W of pure Class A, fully triode, hand-wired assembly. For demanding loudspeakers in large rooms.
