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D Series Power Amplifiers
Operation Manual
1 Welcome
Reliability is the first thing you get with your
purchase of a Crown® power amplifier. The D-
45 and D-75A both deliver dependable opera-
tion with a wide variety of loads. Because of
their exceptional reliability, these amplifiers
have become the leading choice of profession-
als for use in recording studios, laboratories
and public facilities. You can even find them on
the road. Their sonic excellence also makes
them a very good choice for your personal lis-
tening pleasure.
The D-45 and D-75A amplifiers are compact
and provide ultra-low distortion for medium
power applications. Crown’s advanced AB+B
circuitry ensures efficient operation and pro-
tects against shorted, open, mismatched or
low-impedance loads that can affect any ampli-
fier’s performance.
Modern power amplifiers are sophisticated
pieces of engineering capable of producing
extremely high power levels. They must be
treated with respect and correctly installed if
they are to provide the many years of reliable
service for which they were designed.
In addition, D Series amplifiers include a num-
ber of features which require some explanation
before they can be used to their maximum
advantage.
Please take the time to study this manual so
that you can obtain the best possible service
from your amplifier.
1.1 Features
Your dual-channel (stereo) amplifier can
optionally be configured to deliver double the
power from a single (mono) channel. It also
provides the following features:
• Powerful AB+B class circuitry yields maxi-
mum efficiency with minimum crossover
“notch” distortion.
•IOC® (Input/Output Comparator) alerts of
any distortion that exceeds 0.05% to pro-
vide proof of distortion-free performance.
• Signal presence indicators verify the pres-
ence of amplifier output.
• Detented level controls for precise repeat-
ability.
• Ultra-low harmonic and intermodulation
distortion result in the best dynamic trans-
fer function in the industry.
• Very low noise and wide dynamic range.
• High damping factor provides exceptional
loudspeaker motion control.
• Convection cooling system eliminates fan
noise and maintenance.
• Mounts in a standard 19-inch (48.3-cm)
rack.
• Front-panel headphone jack.
• Three Year, No-Fault, Fully-Transferable
Warranty completely protects your invest-
ment and guarantees its specifications.
1.2 How to Use This Manual
This manual provides you with the necessary
information to safely and correctly setup and
operate your amplifier. It does not cover every
aspect of installation, setup or operation that
might occur under every condition. For addi-
tional information, please consult Crown’s
Amplifier Application Guide (available online at
www.crownaudio.com), Crown Technical Sup-
port, your system installer or retailer.
We strongly recommend you read all instruc-
tions, warnings and cautions contained in this
manual. Also, for your protection, please send
in your warranty registration card today. And
save your bill of sale — it’s your official proof
of purchase.