VT-I/F Vacuum Tube Instrument Interface
D.W. FEARN
18
ronment. Experiment with the orientation of the instrument to minimize this
source of noise. Most guitar and bass players will do this automatically, but with
keyboards it may be necessary to rotate and/or move the instrument to find the qui-
etest spot.
Fluorescent lights and SCR dimmers are terrible electrical noise generators.
Turn off the fluorescents. If SCR dimmers must be used, they will generally pro-
duce the least noise in their full-on (brightest) position.
Another source of these hums and buzzes is ground loops caused by the inter-
connection of various AC (mains) powered equipment. A properly-wired studio
should not create a ground loop between the VT-I/F and the studio equipment, but
often a loop is formed when the VT-I/F is connected to an instrument and guitar
amp simultaneously. In this case, use the GND LIFT (3) switch to find the proper
IMPORTANT
When using the VT-I/F with the D.W. Fearn VT-1 or VT-2 Vacuum
Tube Microphone Preamplifier, the VT-1/VT-2 Input switch must
be in the -20 dB position (unless the instrument level is extremely
low). With other preamps, use the input pad and/or reduce trhe
gain of the preamp.
position for minimum noise. If the guitar amp has a “Ground” switch, experiment
with it as well. Be sure to try all combinations of all switches.
The VT-I/F and the guitar amp (if used) should be on the same electrical circuit
(same circuit breaker or fuse) as the studio equipment to minimize ground loop
potential.
Suggestions
You have chosen to use the VT-I/F because of the superior sound it provides. To
gain the maximum benefit from your investment, it is important that you hook up
the VT-I/F so that other factors do not adversely affect the sound quality.
