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13-14. Balanced 1/4" (TRS) & XLR Input Connectors.
These connectors accept input signals on balanced TRS and XLR input plugs.
See the figure at the left for information on polarity. Connectors for each chan-
nel are in parallel; the unused connectors may be used for “loop through” con-
nection to other amplifiers.
NOTE: Unbalanced “Tip/Sleeve” plugs may be used with the balanced TRS
“Tip/Ring/Sleeve” connectors. The “ring” terminal or negative input will be
connected to ground internally. When using three-pole (‘stereo’) TRS connec-
tors, make sure that the ring connection is made either to the cold (–) output of
the source equipment, or to ground. Incorrect connections may cause a 6dB loss
in level.
15. 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
PL Series amplifiers are supplied standard with the XLR configured as “Pin 2 hot” (+). On models PL3301,
PL4601, PL6001, PL7001 and PL8001, an internal jumper makes it possible to alter the amplifier to “Pin 3
hot” (+).
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
On the PL9001, an external XLR polarity switch is featured. (See Appendix E).
Input Sensitivity
The PL Series amplifiers have a standard input sensitivity of .775 Volts for rated power at 8 Ohms. Models
PL3301, PL4601, PL6001, PL7001 and PL8001 are fitted with an internal jumper which allows optional
gains of X20 or X40. Model PL9001 features an external voltage gain/input sensitivity switch (See
Appendix E). Standard and optional voltage gains/input sensitivities are detailed below.
PL3301 PL4601 PL6001 PL7001 PL8001 PL9001
Gain Sens Gain Sens Gain Sens Gain Sens Gain Sens Gain Sens
Standard X45 .775V X61 .775V X68 .775V X86.5 .775V X97.5 .775V X115 .775V
Option 1 X40 .866V X40 1.12V X40 1.32V X40 1.66V X40 1.87V X40 2.24V
Option 2 X20 1.73V X20 2.24V X20 2.65V X20 3.32V X20 3.74V X20 4.47V
NOTE: The internal 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.
Page 8 Crest Audio PL Series Power Amplifiers
Models PL3301, PL4601, PL6001, PL7001, PL8001, PL9001
Tip - Positive (+)
Ring - Negative (-)
Sleeve - Ground ( )
+
2 - Positive (+)
3 - Negative (-)
1 - Ground ( )
PL