O Audio 500W BASH User manual

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 1 of 13
Copyright © 2005
O Audio 500W BASH
®
Subwoofer
Amplifier
User’s Manual

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 2 of 13
Copyright © 2005
TABLE OF CONTENTS
INTRODUCTION...............................................................................................................3
WARNINGS AND CAUTIONS ............................................................................................4
INSTALLATION.................................................................................................................5
CONTROL DESCRIPTION................................................................................................10
SERVICE AND WARRANTY .............................................................................................11
SPECIFICATIONS ...........................................................................................................12

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 3 of 13
Copyright © 2005
INTRODUCTION:
Thanks for purchasing the O Audio 500W BASH
®
Subwoofer Amplifier. This amplifier
features BASH
®
technology which enables a high output power amplifier in a small
package.
Traditional Class AB amplifiers use a fixed voltage power supply. This approach is
wasteful and necessitates extensive heatsinking, particularly for very high power
amplifiers such as this one. Additionally, primitive unregulated power supplies are
typically used that require a substantial, and expensive, transformer to assure
stable supply voltages over a range of load conditions. Inexpensive subwoofer plate
amplifiers typically skimp on the transformer size in the interest of low cost.
BASH
®
amplifier technology marries a robust Class AB amplifier with a smart power
supply that adaptively provides the necessary output voltage required to produce
low-distortion output power. The O Audio 500W BASH
®
Subwoofer Amplifier will
produce up to 500W RMS into a 4Ùload at a Total Harmonic Distortion (THD) of less
than 0.3% and less then 0.05% between 5W –420W. With an 8Ùload, the amplifier
will produce up to 325W RMS at a THD less than 0.01%. Soft limiting circuitry is
active above 325W (into an 8Ùload).
In addition to BASH
®
amplifier technology, the O Audio 500W BASH
®
Subwoofer
Amplifier includes all of the continuously variable controls (output level, phase,
crossover frequency, and parametric equalization) required to properly integrate a
subwoofer into your listening environment. Also, a subsonic filter/low end EQ
control is provided. The 14AWG, 8’long AC cable is long enough to facilitate
plugging the amplifier into a nearby AC outlet. The wire gauge of the provided AC
cable is the same as your house wiring, thus ensuring optimal performance.

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 4 of 13
Copyright © 2005
WARNINGS AND CAUTIONS:
WARNING –THIS AMPLIFIER MODULE IS DESIGNED FOR INSTALLATION INTO A
SUBWOOFER ENCLOSURE, OR INTO ITS OWN ENCLOSURE. WHEN PROPERLY
INSTALLED, ONLY THE EXTERIOR FACEPLATE SHOULD BE ACCESSIBLE TO THE USER –
ANY OTHER CONFIGURATION IS NOT SAFE FOR THE CASUAL USER. IT IS IMPORTANT
THAT THIS MODULE BE PROPERLY HOUSED TO PREVENT ACCIDENTAL CONTACT WITH
DANGEROUS VOLTAGES –BOTH MAINS AC (120VAC) AS WELL AS HIGH VOLTAGE DC
(>42VDC). THESE VOLTAGES CAN INJURE AND KILL AND SHOULD BE TREATED WITH
RESPECT.
WARNING –AS WITH ANY PIECE OF ENTERTAINMENT ELECTRONICS, THIS MODULE IS
INTENDED FOR INDOOR USE. IT SHOULD NOT BE EXPOSED TO WATER (INCLUDING
CONDENSATION).
CAUTION –The amplifier relies on convection cooling, so air must pass freely over
the faceplate. Do not mount the amplifier in a location where faceplate airflow is
blocked. The amplifier does include overtemperature protection and will shut down
if overheated. This thermal protection will automatically reset once the amplifier is
cool.
CAUTION –This amplifier is designed for use with drivers that are rated at 4Ùor
greater. Drivers whose nominal impedance rating is less than 4Ùcan damage the
amplifier. Driver combinations (this includes any configuration where there are
multiple voice coils) that result in a load of less than 4Ù(when calculated using the
driver’s nominal impedance) can damage the amplifier. Damage caused by low
impedance loads are not covered by the warranty.

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 5 of 13
Copyright © 2005
INSTALLATION:
The O Audio 500W BASH
®
Subwoofer Amplifier is designed to be installed into a
subwoofer enclosure or its own dedicated enclosure. Switches and other orifices are
airtight. Also, the back of the faceplate has a gasket to provide an airtight seal when
the amplifier module is mounted into a subwoofer enclosure.

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 6 of 13
Copyright © 2005
INSTALLATION (continued):
Side View:

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 7 of 13
Copyright © 2005
INSTALLATION (continued):
Cutout dimensions are 10.75”H x 9”W.
Electrical connections to the subwoofer amplifier consist of the AC mains input, low
level audio input, and speaker output.
AC mains connections are simply made with the provided AC cable. One end of the
provided cable (IEC320 style receptacle) plugs into the connector located on the
amplifier faceplate –the other end, into a 15A or 20A three-pronged North American
AC receptacle. The amplifier is designed to operate on 120VAC, 60Hz.
Please note that an AC fuse is part of the AC inlet connector. Should the fuse blow,
remove AC power from the unit; then, determine and clear the source of the problem
(such as shorted speaker output). With AC power removed, replace the blown fuse
with the same fuse as specified on the faceplate silkscreen. Replacing the fuse with
a value other than that shown on the faceplate silkscreen will void the warranty.
Low level audio inputs are made via RCA connectors.
In the final installation location, please assure that air can flow freely over the
faceplate.

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 8 of 13
Copyright © 2005
INSTALLATION (continued):
Speaker connections are made to two spade connectors as shown in the following
two photos. Positive and negative are silkscreened onto the PCB under the spades.
Suitable crimp lugs have been provided with the amplifier. Do not connect the
amplifier to drivers or driver combinations that are less than 4Ù(based on the driver
nominal rating). Refer to the last Caution on page 3 for more information.

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 9 of 13
Copyright © 2005
INSTALLATION (continued):

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 10 of 13
Copyright © 2005
CONTROL DESCRIPTION:
Here is a list of controls with a brief description of function. Controls are listed in
order of appearance on the amplifier starting with the upper left:
GAIN –This control is used to set the gain of the amplifier to match the subwoofer’s
output with the rest of your system.
PHASE –This control is used as necessary so the subwoofer does not sound “out of
step”with the rest of your system.
AUTO/ON –When set to the AUTO mode, the unit senses the input signal and
automatically turns on. This action is indicated by the LED (located to the left of the
GAIN knob) turning green. Once the unit does not sense any input signal, then the
unit enters standby mode after 10-20 minutes. This mode is indicated by LED turning
red.
CROSSOVER FREQUENCY –The built-in crossover is a 4
th
order (24dB/octave)
lowpass crossover which may be adjusted from 40Hz to 120Hz. Refer to Chart 2 in
the Specification section for more information.
CROSSOVER BYPASS SWITCH –The built-in crossover can be bypassed by setting
this switch to DISABLED. Refer to Chart 2 in the Specification section for amplifier
frequency response when the crossover is bypassed.
PARAMETRIC EQUALIZATION –The parametric equalization feature consists of three
controls –Q, LEVEL, and FREQ. The parametric equalizer provides an adjustable
notch which is used to tame the effects of room modes. Room modes are
resonances that are a function of a room’s geometry. For more explanation, refer to
http://www.kettering.edu/~drussell/Demos/RoomModes/driving.html or search the
Web using your favorite search engine for “room mode”. Among other effects, a
room mode makes the bass sound tubby and ill-defined at or near the mode’s
frequency. A notch filter can be used to minimize the effect of a room mode. Use the
FREQ knob to set the notch’s center frequency. Use the LEVEL knob to set the
attenuation level. The parametric equalizer is defeated by setting LEVEL to 0dB.
Use the Q knob to set the width of the notch. When the Q knob is set towards the
LOW end, the notch is broad. When the knob is set towards the HIGH end, the notch
is very narrow.
SUBSONIC FILTER AND EQ –This rotary control can be set to 12Hz, 16Hz, 20Hz, or
25Hz and adjusts a combination of low frequency boost and subsonic filter rolloff.
Please refer to Chart 1 in the Specifications section for more information.

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 11 of 13
Copyright © 2005
CONTROL DESCRIPTION (continued):
POWER –Primary AC power control. Works in conjunction with the AUTO/ON switch
(see AUTO/ON switch description earlier in this section).
SERVICE AND WARRANTY:
O Audio warrants the O Audio 500W BASH
®
Subwoofer Amplifier from material or
workmanship defects for a period of one year after purchase. We will provide a
replacement (either new or refurbished, at our discretion) with a full one-year
warranty. Please retain proof of purchase date. This warranty does not cover
damage that results from misuse of this product.
O Audio provides attentive customer service. We want you to be happy with this
product. Please e-mail us at [e-mail] should you have any
questions or comments regarding this product.

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 12 of 13
Copyright © 2005
SPECIFICATIONS (subject to change/correction without notification) :
Audio
Output Power 500W RMS (into 4Ùload @ 0.3% THD)
5W-420W RMS (into 4Ùload @ <0.05% THD)
325W RMS (into 8Ùload @ <0.01% THD)
Frequency Response refer to Chart 1 and Chart 2 below
Chart 1 –Frequency Response for all Subsonic Filter and EQ Settings (note –Crossover
set to 120Hz)
Chart 2 –Frequency Response Showing Range of Crossover Settings (note - Subsonic
Filter and EQ set to 25Hz)

O Audio 500W BASH
®
Subwoofer Amplifier User’s Manual page 13 of 13
Copyright © 2005
SPECIFICATIONS (subject to change/correction without notification) :
Audio (continued)
Minimum Load Impedance 4Ù(based on nominal driver rating)
Signal to Noise Ratio 105dB
Phase Control 0° to 180°
Crossover Range 40Hz to 120Hz
Crossover Topology 4
th
order (24dB/octave)
AC Power
AC Input Voltage 120VAC
AC Input Frequency 60Hz
Max Input Power 600W
Environmental
Ambient Temperature (Operating) 10°C to 40°C
Humidity up to 90% non-condensing
Operating Temp Altitude Derating 2°C per 1,000ft