4
Phase:
Set the phase shift, output/input, 0 or 180 degrees. A green lit LED lamp indicates the
phase shift the amplifier is set.
Power:
Mains On/Off button.
Variable Gain (dB):
Single-turn, logarithmic potentiometer for continuous adjustment of input
signal level. To prevent a power surge, turn the knob fully anticlockwise for maximum attenua-
tion before switching the power on or off. Turning the knob fully anticlockwise till it clicks and
back again activates Reset.
Back Panel
Fig.2.2
Back panel of Type 2719
Signal Input AC
: BNC socket providing a capacitive-coupled input to the amplifier. The
–0.5 dB lower limiting frequency is 15 Hz. Full output is produced by a 2.4 V RMS input signal.
Signal Input DC:
BNC socket providing a direct-coupled input to the amplifier. It enables a
DC offset voltage to be applied for centring the exciter’s vibration table when it is statically
offset by a heavy test object. The input impedance is >10 k
Ω
.. Full output is produced by a
2.4 V RMS input signal.
Voltage Monitor:
BNC socket providing output of the amplifier voltage waveform (including
DC component) for display on an oscilloscope. The monitor signal is the amplifier output
voltage attenuated 20 dB or 0.1 V/V.
Current Monitor:
BNC socket providing output of the amplifier output waveform (including
DC component) for display on an oscilloscope. The monitor signal is the amplifier output
current in 0.1 V/A.
Output:
Power output Neutrik
®
Speakon
®
socket accepting a 4-pin Neutrik
®
Speakon
®
plug or
connecting cable provided for connection of an exciter (see “Output Connections” on page 5).
For a full power output of 180 VA, the moving coil of the exciter or load should have a nominal
load impedance of 0.8
Ω
.
Mains Voltage Selector and Fuse:
Voltage selector for operation of the amplifier from a 100,
120, or 230 V
±
10% (50 to 60 Hz) single phase, AC mains supply. To select the correct voltage
setting or to change the fuse, see “Mains Supply Connections” on page 6.
Mains Input:
Input socket accepting the power cable provided. For connection of a mains
