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Operating Manual - PQX 571 and PQX 572 Parametric Equalizer
1. INTRODUCTION
Congratulations on your purchase of an Ashly
PQX series parametric equalizer. Like graphic equaliz-
ers, parametric equalizers allow you to boost or cut se-
lected frequencies. Unlike graphic equalizers however,
parametric equalizers can tune in the exact frequencies
you want and control the bandwidth of each selected fre-
quency band, resulting in very precise control of frequency
response.
The Ashly PQX series equalizers are a third gen-
eration design including many refinements on our origi-
nal PQ models. Lower noise, greater headroom, addi-
tional filters, full 20Hz -20KHz range on all parametric
filters and additional connector types are the result. The
parametric filters are still based on the “state variable”
type circuit, and a separate summing amplifier is used
for each filter so that no interaction between bands oc-
curs.
2. UNPACKING
As a part of our system of quality control, every
Ashly product is carefully inspected before leaving the
factory to ensure flawless appearance. After unpacking,
please inspect for any physical damage. Save the ship-
ping carton and all packing materials , as they were care-
fully designed to reduce to minimum the possibility of
transportation damage should the unit again require pack-
ing and shipping. In the event that damage has occurred,
immediately notify your dealer so that a written claim to
cover the damages can be initiated.
The right to any claim against a public carrier
can be forfeited if the carrier is not notified promptly and
if the shipping carton and packing materials are not avail-
able for inspection by the carrier. Save all packing mate-
rials until the claim has been settled.
3. AC POWER
Your PQX equalizer should be connected to a
standard 3-wire grounded electrical outlet supplying 120
Volts, 50-60 Hz (some export models are wired for 240
Volts, and are labeled as such). To reduce the risk of
ground loop hum, connect all audio equipment to the same
electrical power source. Removal of the ground pin is
both unlawful and dangerous, as a potential shock hazard
could result.
This unit will perform normally within an AC
voltage range of 94 to 130 volts. Voltages less than this,
as found in “brown-out” conditions, will reduce headroom
and decrease power supply regulation. While this may
affect performance, the equalizer will continue to func-
tion during a brown-out. This unit has an internal line
fuse. In the unlikely event that the fuse should blow,
refer the product to a qualified technician for servicing.
Overall power consumption is less than 15 watts.
4. AUDIO CONNECTORS AND CABLES
4.1 Balanced
Ashly uses electronically balanced inputs on all
equalizers. The inputs and outputs can be used balanced
or unbalanced. Your PQX series equalizer is provided
with three different connector types. 1/4 inch stereo phone
jacks, three pin XLR type connectors, and a terminal strip
will allow interfacing to most professional audio prod-
ucts. The (+) signal is on the tip of the phone plug and
pin 2 of the XLR connector. The (-) signal is on the ring
of the phone plug and pin three of the XLR. To achieve
best performance, we recommend using balanced connec-
tions between all components in your system, as this re-
duces ground-loop induced hum and common-modenoise.
4.2 Unbalanced
If either inputs or outputs are used unbalanced,
the signal is on the (+) connection and the (-) connection
must be tied to ground. A mono phone plug used as an
unbalanced connection will automatically ground the ring
of the jack which is the (-) connection. When using a
stereo plug, XLR connector, or the terminal strip for un-
balanced input or output connections, the signal (-) MUST
be tied to the sleeve, or a significant loss of signal level
may result.