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to the output stages. For the HS, this limiting ¡s accomplished on the
main module and isexplained ¡nsect¡on4.4. Forthe LS, ODEP provides
(via wires labeled ±LL) a signal which limits bias feed to the LS output
devices. This is accomplished through current mirrors Q532 and Q531
(LS NPN quadrant), and Q542 and Q543 (LS PNP quadrant).
Notes
POWER
TRANSISTOR
SPEAKER
LOAD
POWER
TRANSISTOR
VZ POWER SUPPLY
POWER
TRANSISTOR
SPEAKER
LOAD
POWER
TRANSISTOR
VZ
STAGE
VZ
STAGE
Low Voltage, High Current Mode
VZ POWER SUPPLY
POWER
TRANSISTOR
SPEAKER
LOAD
POWER
TRANSISTOR
VZ
STAGE
VZ
STAGE
High Voltage, Low Current Mode
VZ POWER SUPPLY
The VZ supply in the MA-
SOOOVZworks, inconcept, very
much like the MA-3600VZ. For
the sake of completeness,
some conceptual things will be
duplicated here.
VZ means Variable Impedance
and is the ñame of Crown's
patented articulated power
supply technology. It enables
Crown to pack tremendous
power into just 5.25 inches of
vertical rack space.
A power supply must be large
enough to handle the máximum
voltage and current necessary
for the amplifier to drive its
máximum rated power into a
specified load. In the process
of fulfilling this requirement
cónventional power supply
designs produce lots of heat,
are heavy, and take up precious
real estáte. And it's no secret
that heat is one of a power
amplifiers worst enemies.
According to Ohm's Law, the
bigger the power supply, the
more heai the power transistors
must dissipate. Also, the lower
the resistance of the power
transistors, the more voltage
you can deliverto the load. But
at the same time that you lower
the resistance of the transistors,
you increase the current
passing through them, and
again ¡ncrease the amount of
heat they must dissipate.
An articulated power supply,
like VZ, can circumvent much
of this problem by reducing the
voltage appliedto the transistors
when less voltage is required.
MA-5000VZ - 7
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