Architectural & Engineering Specifications
Studio Reference I (120 V, 60 Hz models)
The Crown Studio Reference I power amplifier shall be a solid-state two-channel
model employing multi-mode (AB+B) grounded bridge(TM) output circuitry with a
variable impedance (VZ) power supply for each channel.
The outputs shall be switchable as stereo, bridged-mono or parallel-mono modes
of operation. The bridged-mono mode shall bridge the outputs to provide increased
output voltage. The parallel-mono mode shall parallel the outputs to provide
increased output current.
The power amplifier shall meet or exceed the following performance criteria. Input
sensitivity for rated output: 26 dB voltage gain (unbalanced). Rated FTC output in
stereo mode with less than 0.1% THD: 780watts per channel (20 Hz to 20 kHz) into
8 ohms. Hum and noise: at least 120 dB (A weighted) below full rated output power.
Phase response: +5 to –15 degrees from 20 Hz to 20 kHz at 1 watt. Frequency
response: 20 Hz to 20 kHz, 0.1 dB at 1 watt into 8 ohms per channel in stereo mode.
Damping factor: greater than 20,000 from 10 to 200 Hz into 8 ohms. Intermodulation
distortion (SMPTE): less than 0.005% from full bandwidth power to 78 watts rising
linearly to better than 70 dB at 20 kHz. Harmonic distortion: less than 0.02% at rated
low-distortion 1 kHz power.
The amplifier shall be safe when driving any kind of load—even highly reactive ones.
The output impedance of each channel shall be less than 10 milliohms in series with
less than 2 microhenries in stereo mode.
The variable impedance power supplies shall reduce unnecessary voltage across the
output devices by automatically switching to a parallel mode when less voltage is
required by the output circuitry and to a series mode when more voltage is required.
The amplifier shall contain protection circuitry which limits the drive level placed on
the output devices before their SOA (Safe Operating Area) is exceeded. This protection circuitry shall calculate the instantaneous voltage across and current through
the output devices while factoring in their simulated junction temperatures to predict
how close they are to their operating limits. This protection will be called “ODEP.”
The amplifier shall contain controlled slew-rate voltage circuitry to protect it against
radio frequency interference burnouts. It shall also be protected from current overload at its output stage. The slew rate of the amplifier shall be greater than 30 volts
per microsecond in stereo mode.
The amplifier shall temporarily go into a stand-by mode if its power transformer
becomes excessively hot and shall automatically resume normal operation once it
has cooled to a safe operating temperature.
The power requirements shall be 120 VAC at 60 Hz. At idle, the amplifier shall draw
90 watts or less.
The amplifier chassis shall be constructed of steel with a durable black finish and
shall be designed for flow-through fan-assisted ventilation from the front panel to the
side panels. The amplifier shall have an aluminum front panel with super-gloss Imron
finish and Lexan overlay.
The dimensions of the amplifier shall allow for 19 inch (48.3 cm) EIA standard (RS310-B) rack mounting. The amplifier shall be 7 inches (17.8 cm) tall, 16 inches (40.6
cm) deep behind the rack-mounting surface, and 2.75 inches (7 cm) in front of the
rack-mounting surface.
The amplifier shall weigh 60 pounds, 11 ounces (27.6 kg) and shall have a center of
gravity approximately 6 inches (15.2 cm) behind the front panel.
The amplifier shall be designated the Crown Studio Reference I.
Front-panel controls shall include an enable on/off switch and a detented input level
control for each channel.
Rear-mounted controls shall include a ground lift switch to isolate the signal ground
from the chassis ground, a switch which selects between stereo, bridged-mono and
parallel-mono modes of operation and a reset switch for the AC mains circuit breaker.
Internal controls shall include an input sensitivity switch to select between 0.775 V,
1.4 V or a fixed voltage gain of 26 dB for full rated output.
Crown International
1718 W. Mishawaka Rd.
Elkhart, IN 46517-9439
TEL: 574-294-8200
FAX: 574-294-8FAX
A Crown P.I.P. and P.I.P.2-compatible expansion connector shall be provided behind
an access panel in the rear to accept auxiliary input modules. It shall be fully compatible with the Crown IQ System.
Front panel indicators shall include an amber power enable indicator, an amber ODEP
protection system indicator for each channel which shall normally be illuminated
to confirm the availability of reserve thermodynamic energy and which shall dim
in proportion to limiting when the power demands of the output stages have been
exceeded, a green IOC indicator for each channel, and a green Signal indicator for
each channel which shall normally flash at moderate intensity to show the presence
of an audio signal.
Specifications subject to change without prior notice. Latest
information available at
Crown and Crown Audio are registered trademarks of Crown
International, Inc. Printed in U.S.A.
© 2005 Crown Audio®, Inc.