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4. Balanced inputs - For connecting balanced signal patch cables (XLR).
Explained further on page 8.
5. RCA inputs - For connecting signal patch cables (interconnects) from the
preamplifier to the amplifier to pass signal.
6. Level controls - Option available for the Reference 2220 amplifier. For
adjusting the input level to the amplifier. Explained further
on page 6.
7. Amplifier control muting input/output -
To provide remote switching of mute on/off of the amplifier.
Explained further below.
Control muting
A control is provided on each Reference 2220 amplifier to allow remote switching of
mute on/off. The preamplifier’s control output, such as is provided with B&K series
preamplifiers, can be utilized to provide a control signal to the Reference 2220. If more
than one amplifier is being controlled, the control signal can be extended to include
each successive unit by simply running a 3.5mm mini-jack cable from the CTRL OUT
connector of the first amplifier to the CTRL IN connector of the next unit (commonly
referred to as ‘daisy chaining’). An example of how to connect two amplifiers is
illustrated in figure B.
If a source other than a B&K series preamplifier is used to control multiple amplifiers,
only the control output voltage from the source is critical. It must be within the range, as
indicated on the rear panel, 5-24 volts DC is required. The amplifier will provide each
successive amplifier with a control voltage of 12 volts DC for reliable operation. The
amplifiers control output may be used as a source of 12 VDC @ 125 mA for other user
applications as well. DO NOT POWER MOTORS WITH THIS CIRCUIT.