8
4.0
Input
Section:
Mic/Line/Instrument
Preamplifier
4.1
Preamplifier
Overview
and
Features
Each
of
the
four
preamplifiers
(see
Figure
5)
is
an
all
‐
discrete
microphone/instrument/line
pre
‐
amplifier
designed
to
provide
an
unusually
good
sounding
front
‐
end
for
all
types
of
audio
recording
applications.
Sonically,
it
offers
the
distinct
API
sound,
high
quality
performance,
and
low
noise.
Each
preamplifier
remains
faithful
to
the
circuit
designs
of
API’s
founder,
Saul
Walker.
Fully
featured,
each
carefully
preserves
the
original
sound
character
that
made
it
so
much
a
part
of
the
early
days
of
recording.
Offering
high
headroom
and
a
wide
variety
of
inputs
and
input
access
points,
each
preamplifier
is
equally
at
home
in
the
commercial
recording
studio
as
it
is
in
the
home
project
studio.
Features
Uses
API
2520
Op
‐
Amp
XLR
Mic
Input
¼”
Unbalanced
Input
Front
Panel
Polarity
Switch
Front
Panel
20
dB
Pad
Switch
Front
Panel
Mic
Switch
Front
Panel
48V
Phantom
Power
Switch
4.2
Preamplifier
Controls
Each
preamplifier
provides
a
comprehensive
suite
of
controls:
GAIN:
Preamp
gain
POL:
Preamp
input
polarity
inverter
48V:
Phantom
Power
PAD:
‐
20
dB
microphone
pad/
‐
6
dB
instrument
pad
MIC:
Mic
‐
Instrument
input
selector
Figure
6:
Channel
1
Controls
Figure
5:
Channel
1
Preamplifier
Section
