SPA250 250W Subwoofer Plate Amplifier

Quick Overview

Engineered to provide flexibility, ample power, and reliability, the Dayton Audio SPA250 delivers high fidelity subwoofer amplification and is tailored for home audio and home theater audio systems.

Product Highlights

  • Switchable 6 dB @ 35 Hz bass boost
  • Mono Class AB output stage for solid, well defined output
  • Low-level, high-level, and LFE inputs connect to any system
  • Manual, auto, or triggered on/off modes for compatibility with any automated system
  • Variable gain, crossover point and switchable phase controls optimize room integration
  • Switchable 115/230V input voltage
  • Energy efficient—draws less than 1 watt in stand-by mode

Product Manuals / Spec Sheets / Downloads

Dayton Audio SPA250 User Manual

Buying Options


Dayton Audio SPA250 250 Watt Subwoofer Plate Amplifier

Engineered to provide flexibility, ample power, and reliability

The Dayton Audio SPA250 subwoofer amplifier produces 250 watts of clean power output, and combines with a host of flexible user options to make it an unbeatable choice. The SPA250 features RCA line level and banana jack speaker level inputs and outputs, automatic power-on that is triggered by any audio input signal, and a phase reverse switch to match the subwoofer to your room and your other speakers. A single SPA250 can accept a stereo input signal and combine it into mono, which is preferred for sub bass reproduction. The internal low pass crossover is fully adjustable between 40 and 180 Hz, and of course the amp has built-in protection against internal and external faults.

Key Specs:

  • Channels: 1
  • Power Output @ 4 ohms (RMS): 156 Watts
  • Power Output @ 4 ohms (MAX): 250 Watts
  • Frequency Response: 20Hz - 180Hz
  • Inputs: 2x RCA Inputs, 2X High-level inputs
  • Outputs: 1x Powered Output, 2x RCA Outputs, 2x High-level Passthrough
Phase switch of the SPA250

Phase Switch

Correct misalignment between your speakers and your subwoofer with a phase inversion switch

Crossover of the SPA250

Variable Crossover

Maintain a smooth transition from your full-range speakers with a variable low-pass filter.

High level inputs and outputs of the SPA250

High-Level In/Out

High-Level inputs and outputs let you use any amplifier to feed the SPA250 and send it out to the full range outputs. Perfect for systems with no subwoofer output

Auto On Switch of the SPA250


When no signal is present, the SPA250 can shut itself off until you need it most!

Class-AB Reliability


The classic AB topology keeps distortion to a minimum while providing a peak wattage of 500W to your driver. the SPA250 is perfect for subwoofer duty due to its low noise and reliable performance and protection features.

Showing the SPA250

A-Class Features

On the SPA250, the input and output connections are through your choice of either line level RCA connectors, or high-level inputs for maximum compatibility. A stereo input signal is summed to mono and sent to the internal low pass crossover, which is selectable from 40 to 180 Hz; the input gain sensitivity is fully adjustable as well. Also included is a phase reverse switch, which helps you to achieve the best acoustical match with the rest of your speakers.

A large surface area heat sink is combined with internal overload, thermal, and short circuit protection so that you can expect years of reliable operation.

SPA250 Callouts


1. Low-Level Inputs (Left/Right) - RCA Style jacks that will accept standard line level inputs from a pre-amp level source.

2. Low-Level Outputs (Left/Right) - RCA Style jacks that will pass the line level inputs through

3. High-Level Inputs - Accepts speaker level inputs for connection to amplifiers with no pre-amplified subwoofer output.

4. High-Level Passthrough - allows the speaker level input signal to be passed through to their intended speakers.

5. Power Input - Built-in power cord for connection to 120VAC mains.

6. Volume (Gain) - This control will match the amplifier's input sensitivity to the output of the pre-amp source

7. Frequency (Low-pass crossover) - This sets the highest frequency the subwoofer will reproduce and has a range between 40-180Hz with a slope of 24dB/Oct.


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. 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.

11. Voltage Selection - Selects 115V or 230V Functionality

12. Amplified Signal Output - Connects to the subwoofer driver.



  • Channels: 1
  • Power Handling (RMS): 250 Watts @ 4 ohms
  • Power Handling (MAX): 500 Watts @ 4 ohms
  • Frequency Response: 20 - 180Hz
  • SNR, A-Weighted: 90 dB
  • Total Harmonic Distortion: <0.1%
  • Inputs: 2x RCA Inputs, 2x High-Level Inputs
  • Power Requirements: 115 - 230 VAC
  • Dimensions: 9-13/16" W x 9-13/16" H x 5" D
  • Cutout dimensions: 8-1/2"H x 8-1/2" W
  • Weight: 13.4 lbs.

Model Number SPA250
Color Black
Unit of Measure Each
UPC 844632094897
Warranty - Parts 5 Years
Warranty - Labor 5 Years
Product Shipping Weight (lbs.) 13.4
Product Height 9-13/16"
Product Width 9-13/16"
Product Length --
Product Depth 5"
Amplifier Type Subwoofer Amplifiers
Power Output

156 watts RMS into 8 ohms @ 0.1% THD

252 watts RMS into 4 ohms @ < 1.0% THD

Power Output (RMS @ 70V) Range --
Output Connectors --
Output Types --
Input Connectors --
Input Impedance 10.4K ohms
Signal-to-Noise Ratio 90 dB A-weighted
THD @ Rated Power --
Parametric EQ --
Phase Adjustment 0º (NOR) 180º (REV)
Low-pass Crossover --
Low Pass Adjustment 40 Hz to 180 Hz
Dynamic Range --
Frequency Response --
Efficiency --
Gain --
Bass Boost


6 dB @ 35 Hz

Voltage Requirement --
Auto-on Sensitivity --
Stand-by Power Rating --
Special Features --