D.W. FEARN
VT-12 Microphone Preamplifer
39
L P - 1 L i n e P a d A c c e s s o r y
The LP-1 Line Pad is an accessory for the VT-1, VT-2, and VT-12 Vacuum Tube Microphone
Preamplifiers that allows the preamp to accommodate a line-level signal of approxi4
dBm. This is used when it is necessary for the VT-12 to process a line-level signal, such as in
final processing of a mix.
IMPORTANT: The VT-12 has much more gain than the VT-1 and VT-2 preamps, and the “-
20” pad will be required when processing line-level signals. The gain structure when using the
VT-12 with the LP-1 is not optimum and results cannot be guaranteed. The VT-1 and VT-2
provide a much better match in this situation.
Note that the LP-1 is not designed to be used as a “direct box.”
For most musical instru-
ments, the level and impedance are not correct for use with the LP-1. An exception would be
if the instrument had a professional level, low-impedance, balanced output for recording.
To use the LP-1, simply connect the +4 dBm, balanced signal source (such as the output of a
mixer) to the LP-1 “Input.” Then connect the LP-1 “Output” directly to the input of the VT-
12 preamp. The VT-12 output would then feed the recorder.
The loss through the LP-1 is approximately 43 db. With a +4 dBm input, the output is too
high for the VT-12 in the “0” position of the Input switch. The “-20” position will provide a
better level in most circumstances. However, it may be desirable to use the “0” position in
some circumstances, such as when the line level is particularly low, or when it is advanta-
geous to over-drive the VT-12 to obtain a “fatter” sound. As always, use your ears to deter-
mine which position you find most appropriate for the project.
The LP-1 is a passive device and requires no power. There is little to go wrong with the LP-1,
and no routine maintenance is necessary.
Summary of Contents for VT-12
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