Zed Audio Draconia Instruction & Installation Manual - page 14
Megalith
For those of you acquainted with ancient history we know that the Egyptians amongst
others built massive temples and monoliths. These monoliths were single massive stone
structures, wider at the base and tapering at the top and exuded a feeling of power and
mass. We wanted our new mono block to do the same and we believe that we have
succeeded. With an output capability of 2Kw into a 1 ohm load,
Megalith takes it’s place
as one of the most powerful amplifiers available today.
Megalith is the culmination of more than 2 years of development. We asked ourselves
what consumers want in a subwoofer amplifier. Requirements are for sharp cut off low
pass and high pass filters, good quality equalization, the ability to bridge two amps
together, a remote level control and multiple inputs. We incorporated ALL of these
features into this amplifier.
The heart of any great amplifier is the power supply. After all this is where all the energy is
derived from. A well regulated power supply with low noise is essential for good audio
performance. We at Zed have been building regulated power supplies for over 25 years
and feel that they sound superior to unregulated or “sloppy” power supplies. A small
lesson here. The audio section of an amplifier is only a variable valve from the power
supply to the speaker. How the valve is varied depends on the class of amplifier. In this
case we use a Pulse Width Modulated system (Class D). Any voltage fluctuations on the
power supply rails will manifest themselves as a form of distortion. So if the source of
energy is poor, sound quality will be poor no matter how well the audio amplifier (valve) is
designed. It is synonymous with adding a poor quality fuel to your automobile. It will
perform poorly if the source of energy is poor. The same argument applies to amplifiers.
The PWM amplifier utilizes a high frequency carrier which is modulated by the incoming
audio signal. The resultant series of variable width pulse trains are switched by the main
high current switching amplifier. This section uses ultra high speed precision integrated
circuits to precisely control the on and off times of the output Mosfets. A total of 10 high
current, high voltage Mosfets are used. Each has a current capability of 50 amps in a
circuit limited to less than 50 amps. With an output stage having a current capability of
500 amps there is a substantial safety factor built in. The output filter utilizes low loss iron
cores and high quality film capacitors.
A servo control amplifier monitors the DC conditions at the speaker terminals and keeps
the DC offset at less than 3mV (0.003v).
The turn on/off function of the audio section is done with opto-isolators which allows us to
keep the control circuits fully isolated from the audio circuits.
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