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supply voltage which tends to zero when there is no input signal and reaches its
highest level when the amplifi cation requires power. This supply voltage is continu-
ously variable but always lower than that of an AB class amplifi er and thus a much
higher effi ciency is achieved.
The outstanding energy effi ciency (85%) achieved by this technology, allows very
high output power, without heating up the amplifi er and thus elimination of the
need for excessively large heat sinks.
The power supply itself uses a high speed class D unit in order to constantly supply
the amplifi er with the appropriate level of power.
Thanks to its voltage switching capability a BASH amplifi er plays louder than a con-
ventional amplifi er of comparable RMS power. Simply by virtue of the fact that it’s
not a voltage limited amplifi er it possesses tremendous dynamic power capability.
MFB (Motional Feed Back), servo control
We have given precise timing extremely high priority in the C 80 design. To enable
the relatively compact subwoofer to reach very low frequencies with perfect tim-
ing the C 80 SUB features MFB.
Even at high SPL the sound is precise and distortion very low.
Thanks to MFB the driver “overshoot” is dramatically reduced, dramatically enhanc-
ing timing. The fi gure shown illustrates the overshoot of a woofer with and without
MFB.
MFB controls the woofer and eliminates the overshoot very quickly. Quite simply,
the woofer is able to start and stop correctly.
The MFB circuit works by constantly comparing the diaphragm movements with
the input signal.
The transducer at the back of the diaphragm monitors the movement of the dia-
phragm by measuring its acceleration. In the feedback circuitry the signal is con-
verted to a signal proportional to the speed. The speed is highest at the resonance
Summary of Contents for C 80 SUR
Page 1: ...TECHNICAL DESCRIPTION Jamo C 80...
Page 19: ...19 www jamo com...
