A tube stereo power amplifier completed as an independent amplifier based on the main section of the SQ38F.
Like the SQ38F, NEC's 50CA10 is used for the output tube.
The circuit configuration is based on the Mullard type, and in order to take advantage of the characteristics of the circuit, a low internal resistance ball is used in the first voltage amplification stage to improve the high-frequency characteristics. In this part, 6267 is used in triode connection, and in connection with this, High Gm 6DT8 is used in the phase inversion stage to gain gain. And, like the SQ38F, NEC's 50CA10 triode is used in the output stage.
A phase correction circuit is inserted on the secondary side of the output transformer to prevent the amplifier from becoming unstable due to load attenuation (nearly no load) in the high range where the impedance of the speaker increases.
In addition, in order to avoid the influence of impedance from inputs such as control amplifiers, a buffer resistor is inserted in the first stage grid, and consideration is given to suppressing fluctuations in frequency characteristics caused by changes in volume.
OY15 type is adopted as the output transformer.
The chassis is made of aluminum with a hairline silver finish and is painted a dark gray semi-gloss finish.
This MQ60 also had a model called KMQ60, which is an unwired and unadjusted kit.
| Model | Tube stereo power amplifier | ||||
| continuous output | 30W/30W(4、8、16Ω) | ||||
| Total harmonic distortion | 0.1% (at 1W output) 0.3% (at maximum output) |
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| Frequency characteristic | 15Hz～60,000Hz -1dB | ||||
| SN ratio | 90dB or more | ||||
| residual noise | 0.7mV or less | ||||
| damping factor | Approximately 15(1kHz) | ||||
| load impedance | 4Ω, 8Ω, 16Ω (switchable) | ||||
| Semiconductors used etc. |
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| External dimensions | Width 410x Height 160x Depth 205mm | ||||
| weight | 13.8kg | ||||
| Sold separately | MQ60 kit KMQ60 (¥45,000) Bonnet (¥4,500) |
https://audio-heritage.jp/LUXMAN/amp/mq60.html
