Stealth Acoustics 255R User manual

Full-Range,Whole-House Audio Solutions
Model 255R
250 watt Monaural Amplier with Low Pass Filter
User Manual
Stealth Acoustics
A Division of Dimensional Communications, Inc. | 1220 Anderson Road | Mount Vernon, WA 98274
www.StealthAcoustics.com | Toll Free: 888.865.6800 | Fax: [phone]
User Reference:
Dealer Name
Date Installed
Serial Number

- 2 -
FREQUENCY
50Hz 100Hz
VOLUME
MIN MAX
POWER
OUTPUT
255R MONAURAL AMPLIFIER WITH FILTER
LOW PASS FILTER
PHASE
FULL
RANGE
SUB
0˚
SUB
180˚
180˚
2. 3. 4. 5. 7.6.1.
HI LEVEL
R
L
IN OUT
-
+
-
+
-
+
-
+
BALANCE
R
L
OUT
IN
NO SIGNAL MUTE
LINE LEVEL
AUTOON
L
L
R
IN OUT
SPEAKER OUT
115
INPUT VOLTAGE
115 230
225R MONAURAL AMPLIFIER WITH FILTER
POWER
115V/60Hz
230V/50Hz
FUSE TYPE
T10A 250V FOR 115V
T5A 250V FOR 230V
SERIAL NO
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
WARNING: SHOCK HAZARD-DO NOT OPEN
AVIS: RISQUE DE CHOC ELECTRIQUE-NE
PAS QUVRIR
9. 10. 11. 12. 13. 14.8. 15. 16. 17.
REAR PANEL
8. HIGH LEVEL INPUT – Speaker level inputs are provided to
allow interface with sources that do not provide a line level
subwoofer output.
9. HIGH LEVEL OUTPUT - Speaker level pass-through outputs
connect directly to speakers.
10. BALANCED LINE INPUT – Connect to balance line signal
source. (Pin 1 GND, Pin 2 +, Pin 3 -)
11. BALANCED LINE OUTPUT - Convenience output for
connection to other balance line equipment.
12. LINE LEVEL INPUT - Connect to line level output (RCA
connector) of receiver or pre-amplier.
13. LINE LEVEL OUTPUT – Convenience output for connection
to other line level equipment.
14. NO SIGNAL MUTE SWITCH – This is a 2 position slide
switch. In the far left (ON) position, the amplier is in a
powered up mode. The power LED on the front panel will
glow blue. In the right (AUTO) position, the amplier will
monitor signal input and power up automatically when signal
is received. The LED on the front will glow red until it senses
an audio signal, then blue when it is activated. In this mode
the amplier will power down automatically after 10 to 20
minutes with no audio activity.
15. AMPLIFIER OUTPUT - Binding posts provide output to
subwoofer(s). (Minimum 4 ohm load.)
16. INPUT VOLTAGE SWITCH - Select between 115 volts AC
/60Hz (USA) and 230 volts AC/50Hz (European).
17. POWER SOCKET – AC Power cord plugs into this socket.
Appropriate IEC power cord is provided.
FRONT PANEL
1. CROSSOVER FREQUENCY CONTROL – The crossover frequency is variable from
(far left) 50 Hz to 100 Hz (far right).
2. POWER – Push on, push off
3. WORKING STATUS LED – When the power is on, the LED lights red. When power
is rst turned on the amplier enters a self-check mode followed by a standby mode.
When audio signal is detected the amplier automatically turns on and the LED turns
blue. When amplier the is in the protection mode the LED will show red.
4. OUTPUT SIGNAL LEVEL LED’S - As output increases the LED’s will light from the
bottom up. Top LED indicates clipping.
5. PHASE CONTROL – Push on, push off. Will reverse phase of output 180 degrees.
6. LOW PASS FILTER – The in position will turn off the low pass lter allowing the
amplier to run full bandwidth.
7. VOLUME CONTROL – Clockwise increase, counter clockwise decrease.
Some words of caution:
• Do not attempt to service this
product yourself, as opening or
removing the cover may expose
you to dangerous voltage or
other hazards.
• Do not block intake (bottom front)
or exhaust (rear) vents.
• Do not cycle power switch on
front panel on and off quickly and
repeatedly. Allow 5 seconds for
amplier to complete it’s startup
routine.

- 3 -
TIPS
SPEAKER CONNECTION:
To use the binding-post speaker terminals with bare wire,
unscrew the collar until the hole through the center post is visible
under the collar. Insert the bare end of the wire through the hole
in the post, then screw the collar back down until the connection
is tight. The holes in the center of the collars are intended for
banana-type connectors.
SPEAKER LEVEL CONNECTION:
Use this installation method where the receiver/processor does
not have a subwoofer output or a volume controlled preamp
line-level output. Connect you receiver or amplier’s front left
and right speaker terminals to the left and right terminals on the
255R that are marked “High Level In” (see item 8 Rear Panel
Detail). Connect the left and right terminals on the 255R that are
marked “High Level Out” (item 9) to the corresponding terminals
on the back of your front left and right speakers. This method
will also work for whole house audio distribution systems since
most multi-channel whole house audio ampliers do not have a
line level subwoofer output. If the amp speaker level input is after
a speaker volume control, the 255R volume will track with the
volume control.
LINE LEVEL CONNECTION:
Use this method where the receiver /processor is equipped with a
subwoofer output or a volume-controlled preamp line level output.
Use RCA-type patch cords to connect the line-level inputs on the
255R (see item 12 Rear Panel Detail). If your receiver or amplier
only has one subwoofer output jack, then you may connect the
subwoofer output on your receiver/preamplier to either the left
or right line-level input on the 255R. It makes no difference which
jack you choose.
BALANCED LINE CONNECTION:
This method is used when the 255R is placed between a
preamplier and power amplier that connect with 3-pin XLR type
connectors.
PHASE CONTROL:
The Phase Control determines whether the subwoofer’s piston-
like action moves in and out in phase with the main speakers
or opposite the main speakers. There is no correct or incorrect
setting. Proper phase adjustment depends on several variables
such as subwoofer placement and listener position. Adjust the
phase switch to maximize bass output at the listening position.
Remember, every system, room and listener is different. There
are no right or wrong settings; this switch offers the added
exibility to adjust your subwoofer for optimum performance for
your specic listening conditions. If at some time in the future you
happen to rearrange your listening room, you should experiment
with the phase switch in both positions, and leave it in the
position that maximizes bass performance.
CROSSOVER ADJUSTMENTS:
The Crossover Frequency Control determines the highest
frequency at which the subwoofer reproduces sounds. If your
main speakers can comfortably reproduce some low-frequency
sounds, set this control to lower frequency setting, between 50Hz
– 80Hz. This will concentrate the subwoofer’s efforts on the ultra
deep bass sounds required by today’s lms and music. If you are
using smaller bookshelf speakers that do not extend to the lower
bass frequencies, set the low-pass crossover control to a higher
setting, between 80Hz – 100Hz.
LEVEL CONTROL:
The Volume Control will adjust the level of the subwoofer relative
to the rest of the system. Proper level adjustment depends on
several variables such as room size, subwoofer placement, type
of main speaker and listener position. Adjust the subwoofer level
so that the volume of the bass information is pleasing to you.
The amplier will track input level changes and adjust volume
relative to input source level changes. Front panel level control
determines the maximum level of output.
Functions and Features:
• Rack Mountable - Requires (2) Spaces (3.5”)
• Variable Low Pass Filter
• Auto On/Standby Function
• High Level Inputs and Outputs
• Line Level inputs and Outputs
• Balanced Line Inputs and Outputs
• DC Protected Fixed High Pass Filter
• Standby LED (Red), Blue When Active
• Output Monitor LEDs
• 115 VAC and 230 VAC Input Voltages
• Fan Cooled - 8 Speed Stages
• Phase Switch
Specications:
• Mono Output Power:
250 watts at 8 ohms<0.05 THD
350 watts at 4 ohms<0.05 THD
• THD <0.05 @ 1 watt 4 ohms/100Hz
• S/N 86db Below Rated Output
• Crossover Section:
High Pass Filter: 18 Hz/30db/octave (xed)
Low Pass Filter: 50 Hz to 100 Hz/ 41db/octave (variable)
• Current Draw: 6.2Amps @ 350W/4ohms/115VAC/60Hz
• Dimensions: 19” wide, 3.5” High, 13-3/5” deep
• Shipping Weight: 30 lbs./14 kg.

- 4 -
Invisible
Subwoofers
Subwoofer
Amplifier
Audio
Source
OR...
Use this optional stereo
subwoofer configuration
for increased bass output.
B30
B30
4Ω
4Ω
SINGLE PANEL
SINGLE AMP
DUAL PANEL
SINGLE AMP
(PARALLEL WIRED)
DUAL PANEL
DUAL AMP
QUAD PANEL
SINGLE AMP
350W
4Ω
Leave rear jumpers on
speakers at factory default
“series” positions (16Ω).
Leave rear jumpers on
speakers at factory default
“series” positions (16Ω).
Set rear jumpers on
speakers to “parallel”
positions (4Ω).
Set rear jumpers on
speakers to “parallel”
positions (4Ω).
255R
OR...
1 Amp with 2 Subwoofers
OR...
1 Amp with 4 Subwoofers
B30
4Ω
Homerun each speaker to
ensure correct phase.
Parallel connect all panels at
amplifier.
255R 350W
4Ω
1 Amp with 1 Subwoofer
B30
16Ω
B30
16Ω
B30
16Ω
B30
16Ω
250W
8Ω
350W
4Ω
350W
4Ω
B30
B30
16Ω 16Ω
255R
255R
255R
WHOLE HOUSE
SYSTEM
Pre-amp
GAMING
SYSTEM
Game Console
HOME THEATER
PROCESSOR
Processor
Full Range Audio
Speakers
HOME SPEAKER SYSTEM
*Speaker Level Zone Subwoofer
Speaker Volume Control
Speaker
Feed
MODEL 255R SUBWOOFER AMPLIFIER – CONNECTION EXAMPLES
Rev. 04/12
Notes:
1. The 255R may be utilized as a subwoofer amplier with
the low pass lter set to “SUB” When using the amplier for
full frequency range speaker powering, set the low pass lter
switch to “FULL RANGE”.
*2. When the 255R is connected to a speaker level volume
control as a source feed, the 255R volume will track the
speaker volume control settings.
3. Use convenience pass-through outputs on 255R to feed
additional devices