MACTONE XMA-50 Highest I
¥ 49,500 (around the mid 1960 s?)
Commentary
This is a stereo power amplifier that uses the SEPP method with a 3-pole 6R-A2 tube to achieve sound reproduction without special coloring.
High output is achieved by para-pushing the 3-pole tube 6R-A2.
The circuit uses the vacuum tube SEPP method, which eliminates switching transients (distortion that occurs when the voice frequency is alternately switched between the plus side and the minus side in the output transformer). Moreover, the primary impedance of the output side is low, which results in a wider bandwidth of characteristics, a phase shift phenomenon, and reduced distortion.
An excellent distortion factor is achieved by adopting multiple feedback of more than 20 dB and providing a margin of nearly 10 dB up to the limit value of NF quantity.
Transformer for impedance matching is mounted.
A commercially available 40W class Orient Core has been adopted so that it can operate with sufficient margin even at high output.
Model Rating
| Type | Stereo power amplifier | ||||
| Circuit system | 6R-A2 single-ended, para-push system | ||||
| Rated output | 22W+22W | ||||
| Music power | 27W+27W | ||||
| Frequency characteristic | 10 Hz to 80 kHz + 0 -1dB | ||||
| Distortion factor | 0.8% or Less (Rated Output) Within 0.09% (at 10W output) 0.05% or Less (at 1W Output) |
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| Output characteristic | 15 Hz ~ 30 kHz (Distortion 1%, Rated Output) | ||||
| Input sensitivity | 1.3 V (at rated output) | ||||
| Damping factor | 12 | ||||
| Signal-to-noise ratio | 82 dB or more (maximum gain control) | ||||
| Residual noise | 1 mV or less (minimum gain control) | ||||
| Used vacuum tubes, etc. |
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| Power supply voltage | 100 VAC, 50Hz/60Hz | ||||
| Power consumption | 120VA | ||||
| External dimensions | Width 220x Height 135x Depth 460 mm | ||||
| Weight | 14.5kg |