Sansui - Q-55 'Monaural' Tube amplifier

Sansui Q-55 tube mono power amplifier, one only

This unit was brough up slowly with a variac, tubes did start to heat up but given age of capacitors i did not bring it up to full voltage

Its then sold as is for restoration

Postage to EU only

Info below from internet


A professional-type monaural power amplifier designed for high-fidelity broadcasting facilities such as schools, theaters, coffee shops, halls and studios.

High output and low distortion factor are realized by fixed bias system of GT tube 6CA7PP and large transformer.
In addition to its excellent electrical characteristics, it also has high stability, making it possible to play continuously for a long time.

Equipped with a high impedance terminal and monitor terminal, there is little loss even if the speaker is extended far away. Moreover, the output can be heard at the monitor terminal.

The NF amount of 19 dB (V-NFB) is applied and a damped sound can be obtained.

It is designed with punching metal and 2 tone color metallic paint.

Model Rating
Type Main amplifier
Maximum power output 50W
Frequency characteristic 30 Hz to 20 kHz - within 3 dB
Distortion factor (output 45W) 0.8% or Less (100 Hz)
0.5% or Less (1 kHz)
0.7% or Less (10 kHz)
Signal-to-noise ratio -65dB or more at maximum output
Gain Max. 50W at input 0.78 v
Negative feedback quantity 19dB
Output impedance 250 Ω, 16 Ω (Single Use)
Monitor terminal mounted
Vacuum tube used 12AU7 : 2 Pieces
6CA7 : 2
5AR4
Power supply voltage 100 VAC, 50Hz/60Hz
Power consumption 130 VA (No Signal)
External dimensions Width 391x Height 196x Depth 125 mm
Weight 10.5kg