Internal Configuration And Control - Crest Audio FXA SERIES Manual

FXA
14. Fan Inlet Ports & Filters.
Cooling air enters the amplifier through the fan inlet ports located on the rear of the amplifier chassis. Be
sure not to block these ports when installing the amplifier or other associated equipment. Air must flow
unimpeded through these ports. Fan filters (removable without tools) are provided to minimize entry of dust
and dirt.

Internal Configuration and Control

Input XLR Polarity
FXA Series amplifiers are supplied standard with the XLR configured as "Pin 2
hot" (+). On models FXA601, FXA901, FXA1201, FXA2401 and FXA3601,
an internal jumper makes it possible to alter the amplifier to "Pin 3 hot" (+).
The FXA4801, features an external XLR polarity switch. (See Appendix E).
NOTE: This jumper is NOT user configurable. Please consult your supplier or
local Crest Audio service center if you wish to have the input XLR polarity
changed
Input Sensitivity
The FXA Series amplifiers have a standard input sensitivity of .775 Volts for rated power at 8 Ohms.
Models FXA601, FXA901, FXA1201, FXA2401 and FXA3601 are fitted with an internal jumper which
allows optional gains of X20 or X40. Model FXA4801 features an external voltage gain/input sensitivity
switch (See Appendix E). Standard and optional voltage gains/input sensitivities are detailed below.
FXA601
Gain Sens
Std. X45 .775V
Opt. 1 X40 .866V
Opt. 2 X20 1.73V
NOTE: This jumper is NOT user configurable. Please consult your supplier or local Crest Audio service
center if you wish to have the voltage gain / input sensitivity changed.
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FXA901 FXA1201
Gain Sens Gain
X61 .775V X68 .775V
X40 1.12V X40 1.32V
X20 2.24V X20 2.65V
FXA2401
Sens Gain Sens
X86.5 .775V
X40 1.66V
X20 3.32V
Models FXA601, FXA901, FXA1201, FXA2401, FXA3601, FXA4801
Tip - Positive (+)
Ring - Negative (-)
Sleeve - Ground ( )
FXA3601 FXA4801
Gain Sens Gain
X97.5 .775V X115
X40 1.87V X40
X20 3.74V X20
Crest Audio FXA Series Power Amplifiers
1 - Ground ( )
3 - Negative (-)
2 - Positive (+)
Sens
.775V
2.24V
4.47V