LUXMAN MQ-50
¥ 300,000 (Released in September 1983)
Commentary
This is the first Luxman tube ball type stereo power amplifier that uses GE vacuum tubes.
The output tube adopts a push-pull configuration using highly reliable 6550A/X.
The newly designed 6550A/X UL connection transformer, OY15-Z4K, is used for the output transformer.
A bi-triode 7030/12AU7A is used for the first stage, and by configuring a differential amplification push-pull circuit with a negative power supply, the required gain is obtained while phase inversion is performed.
The driver stage is a push-pull circuit using bi-triode 7024/6AQ8.
In the output stage, a kind of bootstrap circuit is provided in the input circuit to increase the effective impedance of the input circuit so that the driver stage can drive the output stage sufficiently.
The power transformer has a large capacity with a margin.
In addition, as for the structure, the negative power supply at the first stage constant voltage to eliminate the influence of power supply voltage fluctuations.
Model Rating
| Type | Bulb type stereo power amplifier |
| Effective power | 50W + 50W (8 Ω, 1 kHz, both channels operating) |
| Total harmonic distortion factor | 0.1% or Less (8 Ω, 1 kHz, 1W) 1% or Less (8 Ω, 1 kHz, 50W) |
| Frequency characteristic | 10 Hz to 30 kHz (-1dB or less, 1W) |
| Input sensitivity | 1V |
| Input impedance | 100k Ω |
| Signal-to-noise ratio | 100 dB or More (Input Short Circuit, IHF-A Correction) |
| Vacuum tube used | 6550A/X : 4 Pieces 7024/6AQ8 : 2 pieces 7030/12AU7A : 2 pieces |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption | 200W (Electrical Appliance and Material Control Law) |
| External dimensions | Width 410x Height 175x Depth 250 mm |
| Weight | 18.3kg |