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Ming Da MC805-A review
Sound Quality
Measured Performance
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The Ming Da MC805-A produced 14 Watts for 1% distortion and 20 Watts for 3%. The quoted output power of 40 Watts was only approached by putting an 8 Ohm load on the 4 Ohm tap, where 36 Watts was achieved for 3% distortion. This indicates the secondary is incorrectly load matched and needs fewer turns.
    Overload was slow, as usual with single-ended valve amplifiers having limited feedback. Full output was delivered at 40Hz, distortion measuring 2% at 14 Watts, mostly third harmonic from the transformer.
    The meters indicated full output at a 3% distortion level and were accurate enough in showing a realistic overload level for musical peaks. When power is limited meters like this are a good idea I feel.
    Distortion levels were low in the midband and comprised second and third harmonic at lower power levels. Higher harmonics appeared as power increased though, and this is usually due to the output transformer core moving into saturation, a big issue with single-ended valve amps and the reason they have massive transformers. High frequency extension was good from these transformers, considering their size: they reached 38kHz -1dB.
    Damping factor was inevitably low, measuring just 3, so a loudspeaker with good acoustic damping is needed, like a Triangle Antal or similar. Sensitivity was normal enough at 0.76V for full output (i.e. 14 Watts). Noise was low at -90dB and hum a low 1.5mV at 100Hz, just audible close to a loudspeaker.
    The Ming Da MC805-A needs better output load matching to achieve its quoted power output and achieve its full potential. However, with an 8 Ohm load on the 4 Ohm tap it worked properly and gave a decent set of results. NK

Power                          14watts
Frequency response    2.5Hz-38kHz
Noise                          -90dB
Distortion                     0.23%
Sensitivity                   760mV
Damping factor             3.1



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