Stealth Acoustics Stealth Acoustics SA255 Monural Subwoofer Amplifier Invisible Speakers
Stealth Acoustics Stealth Acoustics SA255 Monural Subwoofer Amplifier Invisible Speakers

Stealth Acoustics SA255 Monural Subwoofer Amplifier



The Stealth Acoustics SA255 is an integrated monaural subwoofer amplifier/crossover system designed as a low distortion power source for Stealth Acoustics invisible subwoofer panels or other un-powered subwoofers.  The SA255 can also be used for full range speakers when the low pass filter is off.  Intended for whole house audio or home theater bass applications, the SA255 may stack with other components or mount in a standard 19” equipment rack requiring two RU spaces (3-1/2”) with the provided removable rack mount ears. The SA255 delivers a solid 250 watts into an 8Ω load and 350 watts into 4Ω.  A variable low pass, 18db per octave filter allows for infinite crossover points from 50Hz to 100Hz.

With a full complement of input and output connectors, the SA255 is easily integrated into any audio system. Inputs include RCA line level, balanced XLR line level, and phoenix connector speaker level, all with pass-through capability. The speaker level input/pass-through connections allow the SA255 to feed directly from full-range speaker lines, anywhere in the system. The SA255’s amplifier output connection is via a 5-way binding post designed to accept heavy gauge speaker wires. A selectable automatic turn-on feature activates the amplifier only when audio signals are present. Other features include an internal, quiet, 8-stage cooling fan that automatically engages as required.

Front panel controls include volume control, variable low pass filter, phase control, power switch and six power output monitor LED’s. Rear power controls consist of filter bypass switch for full range operation, no signal mute switch and 3-position panel graphics control switch. 115VAC and 230VAC input line voltages are selectable, via a rear panel switch.

The Stealth Acoustics SA255 subwoofer amplifier is covered by a 2-Year manufacturer’s warranty.


Mono Power Output

250 watts @ 8 < 0.05 THD
350 watts @ 4 < 0.05 THD

Total Harmonic Distortion

<0.05 @ 1 watt 4 / 100Hz

Signal to Noise Ratio

86 dB below rated output

Crossover Section

Low Pass Filter: 50Hz – 150Hz / 18 dB per octave
(variable with bypass switch)

High Pass Filter: 18Hz / 30 dB per octave (fixed)



System Impedance

8Ω nominal – 4Ω minimum

Current Draw

6.2A @ 350W/4 – 115VAC/60Hz


Width: 19” (482 mm)
Height: 3-1/2” (89 mm) – without feet
Depth: 13-5/8” (346 mm)



Black anodized aluminum


Product Weight: 14.20 kg
Shipping Weight: 14.74 kg

Included Accessories

Removable power cord
Removable rack ears

Features and Functions

Rack Mountable

  • (2) RU spaces: 3-1/2” (89 mm)
  • (*Provided rack ears are removed)

DC Protected

  • Fixed high pass filter @ 18Hz

Variable Low Pass Filter

  • 50 to 150Hz / 18 dB per octave

Power Standby LED

  • Red (blue when system is active)


Auto On/Standby Function

  • Switch selectable on/off

Flexible Inputs with Pass Through

  • Binding post speaker level inputs / outputs
  • RCA line level inputs / outputs
  • XLR balanced line inputs / outputs

Amplifier Output Connector

  • 5-way binding post


Output monitor LED’s

  • 6 level readings

Phase Switch

Low Pass Filter on/off Switch

Fan Cooled

  • Automatic – 8 speed stages

110v and 220v Input Voltages

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CHT Solutions has been very prompt to respond and ship the items. I will never hesitate to buy from them again. More power to CHT Solutions!

Richard Y.
Thornleigh, NSW

CHT delivery was incredibly fast, Many thanks all for such an easy purchase process and super fast delivery. 5 stars from me

Chris N.
Malaga, WA

Buying from CHT Solutions was easy and their price was great and I would recommend then to anyone seeking good Hi Fi equipment.

John L.
Woonona, NSW

Fast delivery and great products. Would recommend them to anyone needing great service for sound advice.

Oscar F.
Truganina, VIC

CHT delivered the unit to South Australia within a couple of days. Amazing! Their phone customer service was professional and courteous. Will happily purchase from them again

Robert F.
Tranmere, SA