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Dayton Audio SPA250 250 Watt Subwoofer Plate Amplifier

Brand:| Model: SPA250
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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.
A restocked/refurbished, or Open Box unit of the product is available -- see it now
  • Switchable 6 dB @ 35 Hz bass boost
  • Mono Class AB output stage for solid, well defined output
  • Low-level and high-level 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 120/240V input voltage
  • Energy efficient—draws less than 1 watt in stand-by mode
Part # 
Weight: 13.4 lbs.  
Regular Price$124.80
Sale Price
Dayton Audio Baseball Cap
Qty: 1Part # 520-308
List Price:$19.99
Part # 300-803
Qty:  EA
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Product Details

Dayton Audio SPA250 250 Watt Subwoofer Plate Amplifier

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. A user-configurable bass boost circuit creates a 6 dB peak at 35 Hz, which allows sealed subwoofer designs and certain ported enclosures to achieve their optimum bass extension and maximum "flat" output.

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 amp can accept a stereo input signal and combine it into mono, which is preferred for sub bass reproduction. A preamp or receiver's LFE output may be connected to the SPA250's Left (mono) input. 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.

• Variable low-pass filter at 24 dB/octave attenuation from 40 Hz ~ 180 Hz
• Switchable phase 0° (NOR) or 180° (REV)
• Variable gain MIN/MAX input voltage dependent
• Speaker level high-pass outputs 6 dB/octave at approximately 180 Hz @ 4 ohms, 90 Hz @ 8 ohms (i.e. 220 uF electrolytic capacitor)
• Line-level full bandwidth (10 Hz- 20 kHz) outputs/throughputs for adding or "daisy chaining" additional amplifiers
• Subsonic filter 12 dB/octave high-pass filter centered at 20 Hz
• Damping factor at rated power: 114 @ 100 Hz

Specifications: • Measured 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 • Input impedance: 10.4K ohms • Bass boost: Switchable, 6 dB @ 35 Hz • Low pass adjustment: 40 Hz to 180 Hz • Phase adjustment: 0º (normal) 180º (reverse) • Power requirements: Switchable, 115/230 VAC, 50/60 Hz • Dimensions: 9-13/16" W x 9-13/16" H x 5" D • Cutout dimensions: 8-1/2" W x 8-1/2" H.

Dayton Audio SPA250 250 Watt Subwoofer Plate Amplifier
  • BrandDayton Audio
  • ModelSPA250
  • Part Number300-803
  • UPC844632094897
  • Product CategorySubwoofer Plate Amplifiers
  • Unit of MeasureEA
  • Product Rating
    (124 Reviews)
  • Weight13.4 lbs.
  • California Prop 65

    Warning: California residents only. Please note per Proposition 65 that this product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

View similar products to the Dayton Audio SPA250 250 Watt Subwoofer Plate Amplifier
in the Subwoofer Plate Amplifiers product category.


Dayton Audio SPA250 250 Watt Subwoofer Plate Amplifier
Dayton Audio SPA250 250 Watt Subwoofer Plate Amplifier is rated 4.5645 out of 5 by 124.
Rated 4 out of 5 by from Dayton SPA250 Plate AmpI did quite a bit of research and decided on the Dayton SPA250 for my home-built subwoofer enclosure. After 23 years of using a DBX 150 Mono-Block subwoofer amplifier and one repair bill it didn't owe me a thing. It was time to either have it repaired again or replace it. I've had it connected for a few days and played it twice so far and I'm liking it. I've read about people having issues and replacing certain resistors but for the cost of this unit and the fact that I don't play it that often, I'm hoping it will last for several years. Now that I have a working amp again, it will be most likely be played more often. The bass boost circuit is in an inappropriate location because once mounted in the enclosure that's all you get. If it was top mounted, it could be an easier access. The original cardboard shipping carton was of poor construction and when shipped by you, it was only put in a larger box with hardly no packing material. The Dayton owner's manual isa two page document with no hook up diagram but wasn't an issue due to it being a replacement.
Date published: 2014-11-12
Rated 5 out of 5 by from Fantastic!!!Great sound! Drop in replacement for my Velodyne DLS-3750 subwoofer that went south, screws line right up and were included in the box! Nice quality feel to knobs, controls and jacks also.
Date published: 2014-11-12
Rated 5 out of 5 by from Perfect fitI bought this as a replacement for a little Martin Logan powered sub. It was a direct replacement, hole for hole. Now I have more power and more features at a great price point.
Date published: 2014-11-08
Rated 5 out of 5 by from Excellent drop-in replacement!I had an aging KLH K-SUB10 that recently had the OEM amp die out. Did some quick measurements and this amp fits EXACTLY into the OEM KLH box. Works great! Next upgrade will be the Dayton Mk4 10" woofer to compliment this amp...A+A+A+
Date published: 2014-10-31
Rated 5 out of 5 by from Works w/ Hsu VTF-2 MK2 if you re-drill screw holesThe amp on my Hsu Research VTF-2 MK2 died and I was looking for a replacement. Many people stated in their reviews that this amp is a drop-in replacement. While that is true (the cutout and cables are a direct fit), I found that the screw holes didn't match up.I crudely filled the screw holes with some wood filler, let dry overnight, then re-drilled new screw holes for the new amp. Everything works great with minimal effort.The reason that I filled the old holes with wood filler is that another reviewer stated that he heard a whistling noise from air being forced out of the old holes that went away once he filled them in.
Date published: 2014-10-24
Rated 5 out of 5 by from So far so good for my Onix Rocket ULW 10I purchased this amp about 5 months ago. The amp was a simple drop in and screw installation. Exact fit! It lacks the EQ that was on my original amp and it is rated 50 watts less, but my sub sounds great. Tight, clean, musical and punchy. Just hope the resistors hold up, based on comments of failure.
Date published: 2014-09-05

Product Q&A

Get your questions answered from other customers
who own this product or have experience with it.
If your question requires design or troubleshooting information,
please email  for a prompt reply.
Dayton Audio SPA250 250 Watt Subwoofer Plate Amplifier

I have a Velodyne DSP 3750 that is starting to pop when listening at heavy low notes usually a DTS soundtrack from a movie. It shuts off and I have to turn the amp off and then back on. I think its the amp. Will this amp fit my sub? thanks.

Asked by: meubanks
Please contact our tech support for more help with this question, or 800-338-0531 x1.
Answered by: MattP
Date published: 2014-11-18

Does this amplifier have the capabilities to adjust the EQ filter Q/frequency by changing resistor values similar to how the older #300-794 250w plate amp had? If so, is there a chart available or would it use the same values as the previous model?

Asked by: Brett521
No, we do not publish a chart of resistor substitution values for this amplifier, and we do not advise modifying the component values of the board - doing so will void your warranty.
Answered by:
Date published: 2014-11-20

I would just like to verify that this is a class A/B amplifier.

Asked by: Geoeccentric
Yes this is class A/B.
Answered by: MattP
Date published: 2014-11-11

Hello. I'm mounting the SPA250 plate amp into a non-powered cabinet that allready has a low-pass filter inside. Should I remove the filter or leave it wired to the woofer when installing the amp ? 

Asked by: f250phil
I would recommend taking out the passive filter and using the filter that is built into the amp.
Answered by: MattP
Date published: 2014-10-31

Would this amp be a good replacement for a Energy ESW10, amp died!

Asked by: Silverrain1732
We do not have a cross reference available for this type of thing. Please contact our tech support for more help with this question, or 800-338-0531 x1.
Answered by: MattP
Date published: 2014-10-30

I currently own two ULW10 Subs that have already been replaced with the new Amps from Mark back in 2009, but will 250 watts be enough power for this sub and is there anything else coming down the pipe line that will have more power worth waiting for?

Asked by: GRH5
We do not have a cross reference available for this type of thing. Please contact our tech support for more help with this question, or 800-338-0531 x1.
Answered by: MattP
Date published: 2014-09-23


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