Peavey PVX pSub Operating Manual page 28

Note that at extreme full clockwise settings, the effective gain of the Subwoofer is increased, so if it was on the
verge of clipping before, turning the Bass Enhance Control way up may cause it to go into clipping.
DISCONNECTING AC POWER TO THE PVX p SUB
™
We recommend that the Power switch (3) be used to turn the unit off first, and then the AC power cord can be
removed, this minimizes stress to the power amplifiers and the transducers from turn-off transients. The power
switch has an arc suppression capacitor to help during turn-off, and tends to make a clean disconnect from
the AC power, while the power cord IEC connector can make intermittent contact before finally becoming fully
disconnected, e.g., as when wiggling the cord.
TROUBLESHOOTING
NO OUTPUT AT ALL
First, make sure the unit has AC power and is turned ON. Make sure the LED on the power amp module is
illuminated.
If not, make certain the ON/OFF switch (3) is in the ON position and check the IEC power cord connection (2) by
ensuring it is fully engaged and seated. Make certain the AC line cord is plugged into a working AC outlet.
Finally, check the breaker (1). (See the Rear Panel: Breaker section, for safety instructions.)
Once assured your unit is getting AC power, check that the PVX ™ Sub is getting a signal. Temporarily
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disconnect the cable running to its inputs and connect it to some other device capable of reproducing the signal
(i.e., a power amp and speaker). If this produces a signal, make sure that all Level controls being used have
been turned up to a satisfactory level (one-third to halfway).
If the PVXp Sub has been subjected to direct sunlight or excessive heat, the built-in thermal protection may
have been triggered. If so, turn off the PVXp Sub and let it cool for a sufficient amount of time.
If there is still no output, contact your authorized Peavey dealer or the Peavey International Service Center.
HUM OR BUZZ
If the PVXp Sub is producing a hum or buzz, this can be AC outlet related. Try plugging the PVXp Sub into a
different AC outlet. Sometimes, if a different circuit (breaker) is used for the mixer and for the PVXp Sub, it can
cause hum problems. Unless it is not practical, it is best to use the same wall outlet (breaker) to supply power
to both the mixer and the powered speaker.
Ensure that shielded cables have been used to route the signal to the PVXp Sub's input. If speaker cables with
1/4" plugs are used as input cables instead of shielded cables, they will be prone to hum or buzz.
Hum may be ground loop related. It may be helpful to lift the shield ground (Pin #1) on a balanced cable at
the PVXp Sub end. This is done quite easily by activating the Ground Lift switch (10) built-in to the PVXp Sub.
Check any input changes carefully by first turning down the Level control, before plugging and unplugging
cables, or lifting the shield ground at the Sub.
Check to make sure light dimmers are not on the same circuit as the PVXp Sub, the mixer or any source devices.
If light dimmers are used, then it may be necessary to turn them full ON or full OFF to eliminate or reduce hum.
This is a typical AC wiring/light dimmer interference problem, not a design flaw of the PVXp Sub.
The third wire (ground plug) on the AC plug should NEVER be removed or broken off, as this is a potential safety
hazard.
DISTORTED OR FUZZY SOUND
First, ensure the mixer (signal source) is not clipping or being overdriven. Make sure the Level (6) control on the
PVXp Sub has not been set too low. Check that the input plug is fully seated in the input jack on the rear panel
of the PVXp Sub. Ensure that a power amp has not been plugged into the input jack of the PVXp Sub. If an
extension cord is being used to provide the AC power to the unit, ensure that it is of sufficient current capacity
and that it is not also being used to supply power to any other device.
The PVXp Sub has a built-in bass boost to extend and smooth the natural response of the speakers in the
system, so it should require little, if any, additional EQ. If excessive additional bass boost have been added
externally to the PVXp Sub, it could cause premature overload at high SPL. Reduce the amount of any external
(mixer, rack) EQ and see if that clears up the distortion.