D.W. FEARN
VT-7 Compression Amplifier
19
4 .
O P E R AT I O N
Input
Since the input cable will be carrying high quality audio, it is important that a well-shielded
cable is used. You should strive to minimize the number connectors, patch jacks, switches,
etc. between the source and the VT-7 input.
Output
The output of the VT-7 is line level, transformer balanced. Note that vacuum tube equipment
is more sensitive to load impedance than solid state units. The VT-7 design was optimized for
feeding a balanced bridging input (20k ohms or greater). When feeding a 600 ohm load,
there may be a slight degradation of some of the specifications. In modern studio equip-
ment, bridging line inputs are universal. If the device being fed by the VT-7 has an input ter-
mination switch, that switch should be in the “off” position.
The VT-7 can feed balanced or unbalanced inputs with no need for any modification in out-
put wiring. Either pin 2 or 3 can be grounded, although pin 2 is normally used as the ”hot”
and pin 3 grounded in unbalanced configurations.
Figure 2. VT-7 front panel controls and indicators
Threshold
Harder/Softer
Release
Attack
Gain
Link
Meter switch
Pilot lamp
