Stealth Acoustics 255R: Subwoofer Amplifier for Invisible Flat Panels

A perfect compliment to the B22 or B30 invisible subwoofers, the Stealth Acoustics 255R is a high-quality integrated monaural amplifier/crossover system designed as a high-current, low distortion power source for Stealth Acoustics invisible speaker panels or other unpowered subwoofer speakers.

Intended for whole house audio or home theater bass applications, the 255R may stack with other system components or mount in a standard 483mm equipment rack. The 255R delivers a solid 250 watts into an 8 ohm load and 350 watts into 4 ohms. A variable low pass, 18db per octave filter allows for infinite crossover points from 50Hz to 150Hz and can be bypassed for full-range amplification applications. With a full complement of input and output connectors, the 255R is easily integrated into any audio system.

Inputs include RCA line level, balanced XLR line level, and 5-way binding post speaker level, all with pass-through capability. The speaker level input/pass-through connections allow the 255R to feed directly from full-range speaker lines, anywhere in the
system.

The 255R's amplifier output connection is via a 5-way binding post designed to accept heavy guage 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, low pass filter on/off switch, phase control, power switch and six power output monitor LEDs. 110VAC and 220VAC input line voltages are selectable, via a rear panel switch.

255R Features and Functions

Rack Mountable: (2) RU spaces (3-1/2 inches) - provided rack ears are removable
DC Protected: Fixed Hgh Pass Filter @18Hz
Variable Low Pass Filter: 50 to 150Hz / 18db per octave
Power Standby LED: red (blue when system is active)
Auto On/Standby Function: switch selectable On or 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 LEDs: 6 Level readings
Phase Switch
Low Pass Filter on/off Switch
Fan Cooled: Automatic - 8 Speed Stages
Removable power cord

255R Specifications

System Impedance: 8 Ohms nominal - 4 Ohms minimum
Mono Output Power:
250 watts at 8 ohms<0.05THD
350 watts at 4 ohms<0.05THD
Total Harmonic Distortion: <0.05@1 watt 4 ohms/100Hz
Signal to Noise Ratio: 86db below rated output
Crossover Section:
High Pass Filter: 18Hz/30db/octave (fixed)
Low Pass Filter: 50Hz to 150Hz/41db/octave (variable)
Current Draw: 6.2A@350W/4 ohms/115V AC/60Hz
Dimensions (W x H x D): 482 x 89 x 346 mm
Weight: 13.6kg