Stereo Amplifier: The Cambridge Audio Azur 651 power amplifier
delivers 100 watts x 2 channel into 8 ohms or 150 watts x 2 channel into 4 ohms. The 651W has two pairs of
speaker outputs, allowing you to bi-wire a suitable
pair of speakers, or to drive two pairs of speakers (A&B)
Toroidal Transformer + Dual Mono Design: The 651W uses an audiophile
grade oversize toroidal transformer and substantial extruded heat-sink to
deliver perfect power, with extremely low distortion. Cambridge Audio takes
separate feeds from the large toroidal transformer and process the left and
right amplifier channels separately, effectively making the 651W two mono block
amplifiers put together in one chassis. Benefits of this design include:
- High-quality power output to the amplification circuits, with no
clipping of the waveform signal to provide a consistent signal.
- No transformer noise, buzz, or hum.
- Dynamic bass performance.
- High power output to allow large and demanding speakers to be driven at
high volume levels.
- Large power reserves to allow the transformer to deliver high peaks of
volume when required.
- Full shielded against internal and external electrical interference to
maintain quality of power and signal.
High-Current Output Transistors: Two pairs of high current output
transistors per channel allow the 651W to drive almost any speaker with ease,
with excellent bass response and dynamic control.
Balanced & Unbalanced Analog Inputs/Outputs: The Cambridge
Audio 651W power amplifier is fitted with both balanced (XLR) and unbalanced
(RCA) analog audio inputs to make connection to a Cambridge audio or other
manufacturer preamplifier (sold separately). XLR is a higher-quality input
that can reject noise and interference from equipment with balanced outputs.
Note: Only one type of input (balanced or unbalanced) can
be used. There is a switch on the back panel of the amp which selects
between the balanced or unbalanced inputs.
A&B Speaker Outputs: The Cambridge Audio Azur 651W power
amplifier is equipped with two sets of gold-plated, binding-post speaker
terminals. The speaker terminals can be used to bi-wire a suitable pair of
speaker or to connect two pairs of speakers (A&B). The binding-post terminals
will accept bare wire (up to 10AWG), pin-connects, and banana plugs (dual or
single). Only connect speakers with a nominal impedance of 4- to 8-ohm.
All-Metal Chassis: The Cambridge Audio 651W power amp
features an acoustically damped full-metal chassis with thick brushed aluminum
5-Way Protection System: The 651W benefits from the latest
version of Cambridge Audio's sophisticated proprietary protection system. CAP5
(Cambridge Audio Protection 5-way) is an innovative and intelligent circuit that
constantly monitors the amplifier, without degrading signal purity, ensuring
ultimate reliability. Designed to protect the amp in operation, the system has
been developed to leave sound quality unaffected. It incorporates a clipping
sensor that reduces the volume to keep levels in a safe range, short-circuit
detection, and current and voltage overload detection plus a solid-state
temperature sensor for over-heat cut out. Combined, these technologies ensure
that Cambridge Audio amplifiers will go on to deliver years of reliable,
- DC Detection: CAP5 offers loudspeaker protection if the
output of the amplifier goes to a high constant voltage (DC).
- Over Temperature Detection: AP5 includes temperature
detection which constantly monitors the heat generated by the output
transistors. If the monitored temperature reaches a high level (suitably
within the limits of the output devices) the amplifier will automatically
switch into a fault mode.
- Over Voltage Detection: CAP5 offers V/I protection by
constantly monitoring the output transistors to keep them working inside
their Safe Operating Area (SOA). The SOA is a set of limits given by the
output transistor manufacturer to ensure reliability. V/I also protects the
amplifier against short-circuits on the speaker terminals during use.
- Short-Circuit Detection: During power up from Standby,
CAP5 performs a check on the loudspeaker terminals to see if a short across
the terminals has been accidentally introduced. If the resistance measured
across the loudspeaker terminals is too low, the unit will remain in Standby
mode until the fault has been removed and power up is re-attempted.
- Intelligent Clipping Detection: CAP5 has the ability to
detect when the amplifier starts to clip or overdrive at its output, which
can damage loudspeakers and degrade the sound. Clipping distortion is caused
at high volume levels when the output signal briefly goes outside the
maximum voltage that the amplifier can provide, causing the tops of the
signal to flatten off. When CAP5 detects clipping, the volume will be
automatically nudged down until CAP5 detects an undistorted output.
IR Input/Control Bus: The 651W also features a IR Emitter
input (3.5mm) which allows modulated IR commands from multi-room systems or IR
repeater system to be received by the amplifier. In addition, the 651W features
a Control Bus Input and Output (RCA), which allows un-modulated commands from
multi-room systems or other components to be received by the amp and loop out to
Trigger Input/Output: For custom install use or with preamps
and with trigger outputs, the 651W can be turned on and off (i.e. brought in and
out of Standby mode) by the presence of 5-12V DC at the Trigger input (3.5mm). A
trigger input will also produce an internally generated 12V DC trigger output at
the Output/Thru connection (3.5mm). Turning the 651W on from the front panel
also produces a 12V DC trigger output at the Output/Thru connection. This can be
used to turn on/Standby other connected power amplifiers or other equipment if
Auto-Detect Mode: The 651W features an Audio Detect mode. When an
audio input signal is detected, the 651W will automatically power up. When the
audio signal stops, it will then automatically power down after 30 minutes.
Our Product Research Team
At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere.
That's because we have our own in-house Product Research team — they open the box,
verify contents, check the owner's manual, and record dimensions, features and specs.
We stay on top of new products and technologies to help people make informed choices.