Krell Industries Evolution One - Manual (Page 13)

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9
Separate Power Supplies Are Quiet and Powerful
Housed in a separate chassis, the power supply makes use of extensive electri-
cal and magnetic shielding to keep radiated interference out of critical amplifier
circuits. Internal high current line conditioning circuitry filters RF noise on the
AC mains, as well as compensating for asymmetric power waveforms and DC
on the mains. A dedicated 165 VA toroidal transformer with six independent
secondary windings powers the amplifier’s low level stages, gain stages, and
control circuitry. Power for the high current regulators and amplifier output stages
comes from two massive 2500 VA toroidal transformers. These in turn drive eight
35-amp bridge rectifiers and 120,000 microfarads of filter capacitance. High relia-
bility connectors with 56 machined, gold plated, 20-amp contacts transmit these
tremendous power reserves to the regulators.
Advanced Microprocessor Control Monitors
Critical Operational Parameters
If the DC level at the amplifier inputs exceeds a safe level, the microprocessor
control automatically switches in DC blocking capacitors to prevent damage to
the input stages or the loudspeakers. The microprocessor control measures the
load impedance in real time to optimize the performance of the amplifier and
power supply or, in the case of a short circuit, to shut the amplifier off. It monitors
the regulator output voltages, the symmetry between the two halves of the bal-
anced output stages, and it monitors the operating temperatures of the three
main heat sinks. If any of the heat sinks become too hot, the microprocessor
control adjusts the operating parameters of the amplifier and power supply to
help the circuitry run cooler. If the temperature of any of the heat sinks becomes
unsafe, the microprocessor control shuts the amplifier off until it cools down.
In the event of a major protection fault the microprocessor flashes a diagnostic
code on the power/stand-by LED (4). The RMS output voltage and current sig-
nals used by the microprocessor are also used by the power meter (6) (7), on the
amplifier front panel, to display accurate power measurements. For more infor-
mation on diagnostic codes, see Amplifier Troubleshooting, on page 26.