Page 1
250W SUBWOOFER
PLATE AMPLIFIER
Model: SPA250 User Manual
Page 2
Thank you for purchasing the Dayton Audio
®
SPA250 Subwoofer Amplier. It has been designed and built to provide
years of high quality sound reproduction, and is ideal for use in both home stereo and home theatre systems. The
amplier has been engineered to include features like a choice of high or low level audio connections, selectable crossover frequency, auto on/off circuit activated by input signal, and comprehensive internal production against shorted
speaker loads, thermal faults, and overload conditions.
FEATURES:
• Line-level and speaker-level inputs for connection to
any system
• Auto-on circuit comes on the instant the amp is needed
• Soft-clip circuitry provides clean output even with demanding
program material
• Full complement of protection circuits for extreme reliability
• Switchable bass boost
• Reversible phase switch for best integration with satellites
• Variable frequency 4th order low-pass crossover for a
clean transition to main speakers
• Advanced soft clip circuitry improves headroom and
protects woofers
• Switchable 115/230V input voltage
• Complies with Energy Star and CE EuP directive
Bass Boost
O/On
The trade mark is shown on the rear
plastic housing near the speaker wire
(2)
Page 3
INPUT/OUTPUT CONNECTIONS
1. Low-Level Inputs (Left/Right)
RCA style jacks that will accept standard line level inputs from
a pre-amp level source. They will accept a stereo signal and
internally combine it into mono. Both left and right input jacks
must be connected to the source in order to drive the amplier
to full output. Note: If using a LFE output from a preamp or
receiver connect it to the Left (mono) input.
with the amount of “overlap” that you will experience when all
speakers are playing in the same range. This can be helpful
when integrating the subwoofer with the rest of the system and
with the room. Note: When using the amp with a LFE (Low
Frequency Effects) output on a pre-amp or home theatre re-
ceiver the internal low pass lter circuitry should be bypassed
by turning the frequency control to maximum (180Hz). The
home theater receiver should be used to control the low pass
crossover frequency.
2. Low-Level Outputs (Left/Right)
This output allows the low level input signal to be daisy chained
to other ampliers. The low level input is simply passed
through with no alteration (EQ) to the original signal.
3. High-Level Inputs
Speaker level inputs using binding post type jacks to permit
connection with banana type plugs or spade terminals. Allows
the user to connect the speaker level output of a full range
amplier to the input of the subwoofer amp using standard
speaker wire. A mono signal is derived from the stereo, which
then feeds the subwoofer amplier crossover input.
4. High-Level Outputs
Speaker level outputs using binding post type jacks to permit
connection with banana type plugs or bare wire. Used to connect from the subwoofer amp to pass signal from the full range
amp on to the main L/R speakers. Signal is only present on
this output if the high level input is also used. The signal to
the L/R speakers will be shaped by an internal 6 dB/octave
125 Hz high pass lter.
5. Power Input
This unit features an IEC type power jack. This allows the
user to change the power cord depending on the country
and voltage used. The IEC jack also houses an integrated
fuse holder that contains the AC line fuse. The unit is set at
the factory for 115V operation. It is supplied with a 5 A, 250V
fuse and USA type power cord. In most 230V applications a
separate power cord and 2.5A, 250V fuse will be required
and are not included.
CONTROLS/INDICATORS
6. Gain
This control will match the amplier’s input sensitivity to the
output of the pre-amp source. If the source output has a variable control, we recommend that the user spend a moment or
two determining the best balance between the two controls.
When a balance is found between low noise, linear level
control, and sufcient level to drive the amp to the required
output, the gain knob can be considered to be the “volume
control” for the subwoofer system.
7. Frequency
This control is used to establish the highest frequency that
the subwoofer will reproduce and has a range between 40 to
180 Hz with a slope of 24 dB per octave. If you are using the
system for music and your main speakers have good bass
capability, you could set the control to a fairly low value at 40,
60, or even 100 Hz. If the main speakers are smaller or do
not have much bass output, set the control higher. Experiment
8. Power LED
When the power switch is moved to the “on” position, the LED
will illuminate green, and the amp will be in “On” mode. When
set in the “Auto” position the unit will be in the stand by mode. In
this position, if a low level signal of about 10 millivolts or greater
is applied to the input, the light will change green to indicate
that the amplier is fully operational and receiving typical music
program. If an input signal is not detected for 10 to 15 minutes,
the amp will go back to “stand by” mode and the LED will turn
off. If the protection circuit detects a short circuit or thermal
overload the unit will shut down and the LED will turn red.
9. Power Switch
On, Off and Auto mode. When the “Auto” position is selected,
the amp is in “stand by” mode until an input signal of about
10 millivolts or greater is detected. The amp will go back to
standby mode 10-15 minutes after the input signal stops.
10. Phase
This two-position (NOR = 0° phase and REV = 180° phase)
switch helps to compensate for differences in the acoustical
and electrical characteristics between the subwoofer and the
main system speakers. The relative locations of speakers
in the system can cause signicant disturbances in speaker
interaction due to time delay issues, or the destructive phase
interferences that can occur at certain frequencies. The use
of this switch in conjunction with altering the location of the
subwoofer can have a dramatic effect on system integration.
The “NOR” setting would be considered the normal or default
setting, but be sure to experiment during system set-up.
11. Voltage Selector Switch
This switch allows the user to select 115V or 230V operation.
The unit is set at the factory for 115V operation and contains
a 5A, 250V fuse. When operating at 230V be sure to change
the fuse to a 2.5A, 250V fuse.
12. Output Lead for Subwoofer Driver:
This rear mounted output lead connects the amplier to the
subwoofer driver. The output lead is roughly 20" long and
is color coded. The red wire uses an insulated .250" quick
disconnect and the black wire uses an insulated .205" quick
disconnect. These connectors can be easily removed if your
driver requires another size or type of connector. Be sure to
observe proper polarity when connecting the amplier to your
subwoofer driver (red = positive, black = negative).
13. Bass Boost:
Selects a bass boost lter with +6dB @ 35Hz. Allows the
user to add boost to the low end response. Remove plug to
access switch NOTE: DO NOT attempt to change bass
boost setting when ampliier is turned on.
(3)
Page 4
NOTES ABOUT HUM:
While the SPA250 has been designed to minimize the possibility of hum in the subwoofer system, it is still possible that a hum
will occur in rare circumstances. Its safety grounding can create a path for small amounts of 60 Hz energy to travel through
the line-level audio system. Although not dangerous, this energy can cause dif culty with the subwoofer auto signal sensing
circuit, and at the very least will interfere with the quiet enjoyment of your system. The rst course of action should be trying to
make sure that all of the audio components are connected to either the same electrical outlet, or at least into the same circuit
branch. Next, cable TV systems are notoriously the culprit, so be sure to try disconnecting all coaxial feeds that are connected to the system. If this solves the problem, install a coaxial line isolator and reconnect the system. In the very worst case, a
line-level audio isolator/transformer connected to the line-in of the subwoofer ampli er will usually solve the problem.
SPECIFICATIONS:
Rated Power Output: 156 watts RMS into 8 ohms @ 0.1% THD
252 watts RMS into 4 ohms @ < 1.0% THD
Signal to Noise Ratio: 90 dB A-weighted
Ef ciency: 66%
Input Impedance: 10.4K ohms
Bass Boost: Switchable, 6 dB @ 35 Hz
Low Pass Adjustment: 40 Hz – 180 Hz
Phase Adjustment: 0° (NOR) or 180° (REV)
Dimensions: 9-13/16" W x 9-13/16" H x 5 D
Enclosure Cutout: 8-1/2" x 8-1/2"
Power Requirements: 115/230 VAC, 60 Hz/50 Hz, 400W
Stand-By Power Rating: 115, < 0.29W*
Weight: 11.7 lbs.
* The SPA250 complies with ENERGY STAR and CE EuP directive.
IMPORTANT SAFETY INSTRUCTIONS
Read these instructions – All the safety and operating instructions should be read before this product is operated.
Keep these instructions – The safety and operating instructions should be retained for future reference.
To reduce the risk of electric shock, do not remove cover. No user serviceable parts inside. The unit should be connected to an earth grounded AC electri-
cal socket. Do not defeat the safety purpose of the polarized or grounding plug. If the provided plug does not t into your outlet, consult an electrician for
replacement of the obsolete outlet. Refer servicing to quali ed personnel. To reduce the risk of re and shock do not expose unit to rain or moisture. Clean
only with dry cloth. Unplug the unit during lightning storms or when unused for long periods of time.
The unit should be operated in a well ventilated area. Minimum clearance is 2 inches from the ventilation openings. Do not install near any heat sources such
as radiators, heat registers, stoves, or other apparatus (including ampli ers) that produce heat. Protect the power cord from being walked on or pinched,
particularly at the plugs, convenience receptacles, and at the point where they exit the unit. Only use attachments/accessories speci ed by the manufacturer.
Note: Unit is set at the factory for 115V operation. Be sure to change the fuse to a 2.5A rating before switching to 230V operation.
This device can be sold in all EU regions
5-Year Warranty
See daytonaudio.com for details
daytonaudio.com
tel + 937.743.8248
info@daytonaudio.com
(4)
705 Pleasant Valley Dr.
Springboro, OH 45066
USA
© Dayton Audio®Last Revised: 7/19/2023
Loading...