Page 5 13006 rev 0005
5. Level controls - For adjusting the input level of each channel into the
amplifier. There are level controls on the back of the
amplifier. One level control for each channel. Explained
further on page 6.
6. 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 3220 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 3220. 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.