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Ming Da MC805-A review
Sound Quality
Conclusion
Measured Performance
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MING-DA MC805 SINGLE ENDED CLASS A VALVE AMPLIFIER

 

 

 

Da truth

 

The Ming Da MC805-A Single-Ended valve amplifier delivers a truthful sound, Noel Keywood finds.


If there’s an amplifier that is mythically perfect, it is the Single-Ended, or SE. In real life they are anything but perfect, but most people acknowledge that sound quality wise, they are unbeatable. I wouldn’t say an SE shades all else, but they are always delightfully solid sounding, putting more meat on the bone it always seems to me, than your everyday push-pull types. And here to demonstrate and prove the point are a pair of Ming Da MC805-A monoblock Single-Ended power amplifiers. Feeding them in this review was an updated MC 300-PRE preamp, tweaked by the UK importers to eliminate the problems I experienced with it (see our  September 2011 issue).  
    By definition Single-Ended amplifiers lack crossover distortion, but to be truthful they don’t lack distortion, so their notional perfection is just that. The reality is a little different from the rosy picture some paint of the SE, but at the same time I have yet to hear a bad one. In spite of the difficulties of their design most SEs are valve amplifiers. Few transistor Single-Ended amplifiers exist, because audio transistors run burning hot in this role, but in the UK Tellurium Q and Sugden make them. Valve amplifiers need gapped output transformers able to withstand direct-current passing through them without suffering magnetic saturation (overload). And they need massive cores as well, making valve SE amplifiers very heavy, unless power output is limited. So as you might guess most SEs are low power amplifiers, in order to make them liftable, and they are usually monoblocks too, just to make them physically manageable. And that describes in outline the Ming Da MC805-A monoblock power amplifiers reviewed here. Each one weighs 22kgs, heavy but liftable, and measures 230mm wide, 480mm deep and 240 high, at least with 805s lacking top caps as fitted to our amplifiers. Power output is quoted as 40 Watts but ours produced way below under test (see MEASURED PERFORMANCE). It sounds little, but in use the meters showed that, as usual, very little power is used in normal daily use and I never got the meters near their red overload zone.
    Each amplifier uses a single 805 power triode, two 6SN7 small signal triodes and a Chinese 6P3P (6L6) acting as a driver. Our amps had ‘different’ valves to those shown on the UK website or on the web generally. This is because there are numerous variants of the 6L6 and 6SN7, both in shape and designation and the UK importers prefer the standard tubular 6SN7 to the 'Onion bulb' variant, that may look good but is microphonic. You will even see 805s with anode top caps being used, but since the cap is probably carrying 800V or so, you will not find such a tube being used in any country with safety laws!
    The rear panel carries an 8 Ohm output with a 4 Ohm tap, plus a single phono input socket. Mains power is switched on by a rocker switch lurking on each left side, just behind the front panel.  Power amplifier switch-on was fuss free; there was no thrum from the transformers nor any switch on thump. Like most valve amps these run up slowly and smoothly, the big 805s emitting a bright glow from their thoriated tungsten heaters.
    Feeding the monoblocks was the aurally impressive MC-300 preamplifier. Ming Da UK have eliminated the bass peak I found under review by changing feedback capacitor values, and cured excessive microphony by fitting non-microphonic 6SN7 valves.  The MC300-PRE has balanced inputs and I fed it from the balanced outputs of our Electrocompaniet ECD1 DAC. Outputs are unbalanced phono sockets that feed the power amplifiers.



 

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