D.W. Fearn VT-1 Operating instructions manual - page 20
D.W. FEARN
VT-1 & VT-2 Microphone Preamplifers
20
if necessary. (Call the factory for detailed instructions). The ground pin of the power cord is
internally connected to the chassis. This configuration is standard in professional equipment
and is required by most electrical codes. A grounding screw is provided on the back panel for
installations that use separate chassis grounding. If ground loop hum is detected, a careful
check of the studio grounding scheme is needed. The VT-2 is less susceptible to grounding
problems than many studio devices.
Connections
(see Figure 1)
The INPUT connectors are XLR-3 females wired with pin 1 ground, pin 2 “+” or “high,” and
pin 3 “-” or “low.” The input matches 150 ohm (nominal) microphones and is transformer
balanced.
The OUTPUT connectors are XLR-3 male wired with pin 1 ground, pin 2 “+” or “high,” and
pin 3 “-” or “low.” The VT-2 is optimized for feeding balanced bridging inputs. (Virtually all
modern audio equipment has bridging inputs.) The output is transformer-balanced.
The “GND” terminal is for use when an external grounding scheme is utilized.
The Fuse is a 3AG-type 1 amp for 100 or 120 VAC operation, and 0.5 amp for 220-240 volts.
The AC input connector is used with the mating line cord (supplied). For 120 VAC operation,
this cord is a Belden 17250 or equivalent.
The unit does not utilize any RFI filtering, and no RFI has been experienced, even when the
VT-2 is operated in close proximity to AM, FM, and TV broadcast transmitters.
Input and Output Connections
See Figure 1. Gold-plated XLR connectors are used for inputs and outputs. The input connec-
tors are female and the outputs male.
Figure 1. The VT-2 rear panel connectors