Dayton Audio's SPA250DSP true 250 watt digital switching plate amplifier features advanced signal processing control that every audio enthusiast wants. This power and flexibility is accessible via PC-GUI software and our innovative single-knob LCD control panel.

1. Power Mode: Select the either energy-saving or “always-on” power mode
• Auto: Amp goes into standby after no detected signal input for 20 minutes*
• On: Amp is always on, regardless of input signal status.
* Amp will automatically turn on typically in one second or less once audio signals are resumed.

2. Analog input attenuation: Affects analog balanced and unbalanced inputs only.
• Normal: No attenuation.
• Hi: Attenuates input signal by -6dB.

3. USB Control: Used for PC-GUI communication with custom PC software included with your amp.

4. Feature Control: Single knob digital actuator with single/double-click enabled with rotary scrolling to navigate the amp’s extensive feature menu.

5. Limiter LED: Lit when Limiter is active (Red).

6. Standby/On LED:
• Red when amp is in energy saving “stand by” state.
• Green when amp is operating normally.

Volume/Phase

• USB link indicator: When the communication via USB with amp is successful, the GUI’s LED indicator will light green. Otherwise, LED stays red.
• Processing Selection: Navigate across the DSP menu to adjust various DSP parameters.
• Sub in/out monitor: Monitor the input signal and sub output signal levels.
• Tools Drop Down Menu: Utilities for amp DSP management.
• Volume: Adjust the level (gain) of the subwoofer output.
• Phase: Continuously adjustable phase from 0° to 180°.

Low Pass and Subsonic Filters

• Filter ON/OFF Button: Enable or disable the selected filter.
• Slope: Select roll-off gradient of the selected filter: -12dB/-24dB per octave.
• Frequency (Hz): Adjust cut-off frequency of the selected filter

5-Band Parametric Equalizer

• PEQ Window: Graphical trace is NRT editable. Bands can be shaped by cursor or direct input and/or
sliders
• 5 Band-digital PEQ adjustments:

a) Band On/Off: Bypass or enable by clicking the colorized 1~5 buttons
b) Center Frequency (CF): Adjust Center Frequency of each EQ band, 10~200Hz, steps: 1Hz.
c) Gain: Adjust the EQ gain (apparent volume), -12 ~ +6dB, steps: 0.1dB
d) Q (EQ width): Adjust the “Q” value, 0.4~16 , step: 0.1

Dual-Band Limiter

a) Threshold: Adjust the limiter threshold, 0~-12dB, step: 0.1dB
b) Attack: Adjust limiter’s “attack time”. This controls the time taken to attenuate signals over the
threshold to the specified threshold level. Range: 1/5/10/20/100ms
c) Release: Adjust limiter's “release time”. When signal is below threshold level, this controls the
time taken to restore back to original level. Range: 60/120/240/480/1000/2000ms
d) Frequency: The crossover frequency point between the 2 bands: Band 1 (Low Frequency) &
Band 2 (High Frequency).

High Frequency Out

• This block controls the DSP parameters for line level output only.
• Delay: Adjust the time difference between High Frequency out and Subwoofer out.
• HPF Control:

Filter ON/OFF: Bypass or Enable the selected filter.
Slope: Select roll-off gradient of the selected filter: -12dB/-24dB per octave.
Frequency: Adjust cut-off frequency of the selected filter.

Specifications: • Power output: 250 watts RMS into 4 ohms, THD+N <0.1% • Signal to noise ratio: 97.9 dB (A-weighted) • Power requirements: 110~120/220~240 VAC selectable, 50/60 Hz • Amplifier dimensions: 10.25" H x 7.25" W x 2.125" D; Amplifier cutout: 9.25" H x 6.25" W.