LaChapell Audio 503 500 Series EQ - Manual (Page 4)

583S mk2 Controls:
2
Input Gain Control: Provides variable control
over how much input source signal is driven onto
the vacuum tube. Specifically, this control is posi-
tioned after the Jensen input transformer and just
before the 12AX7 tube. Think of this control as
your “throttle” for tube coloration/harmonics
(distortion).
Phantom Power (48v): This toggle provides a 48
volt supply of DC current for all condenser micro-
phones. Each 983S is calibrated to exactly 48V
during final assembly.
20dB Input Pad (-20): When engaged, micro-
phone input source signal is reduced by 20dB.
Specifically, this action occurs before the Jensen
input transformer.
CREATIVE TIP: For near
transformer-less sound, consider engaging this
pad function and compensate for the loss of gain
by increasing the input gain control. This ap-
proach effectively minimizes the gain coming
from the Jensen input transformer while drasti-
cally increasing the character of the vacuum tube
(this is only possible with the microphone path).
Polarity Reverse: Reverses the polarity of the
output line level signal.
Hi-Z Input: The auto-switching Hi-Z input stage
is transformer-less and operates with an input
impendence of 100Kohm. It cannot make use of
the -20dB pad.
Output Gain Control: Provides variable
control over line level signal strength. Think
of this control as your source for clean gain.
Typically, this control is used to establish the
desired line level after the input gain has
been set.
250V Indicator: This LED will illuminate
green when the internal 250 volt DC/DC
converter has the required input/program
voltage to function properly.
Pull Handle: This should be used for instal-
lation or removal of the device. It also assists
in protecting toggle switches.
Pull Handle
Phantom Power
20dB Input Pad
Polarity Reverse
Hi-Z Input
Output Gain Control
250V Indicator