Scalar - SR900

The HH Scalar series of amplifiers are the perfect complement to any passive PA cabinets, whether monitors, front of house or subwoofers.

Efficient, lightweight switch-mode power supplies and high quality Class H amplification circuitry ensure perfect sound and effortless power from surprisingly light and compact amplifiers, whilst still maintaining impressive bass response.

Styled with a nod to our much respected amplifier heritage, these are nonetheless thoroughly modern high performance amplifiers with all the flexibility, performance and reliability required for today’s live music scene.


The dual Class H power stages each deliver a full 450W RMS into a 4 ohm load, whilst in Bridge mode the amp delivers 900W into 8 ohms via the binding post connections on the rear panel. A perfect amp for driving small PA systems, monitors and high mid cabs.


  • 2U Rackmount Power Amplifier
  • 2 × 310W stereo, 900W Bridged (EIA standard). (8 Ohm load)
  • 2 × 450W stereo EIA standard. 1200W Bridged (40ms 1kHz burst 1% THD) (4 ohm load)
  • 2 × 600W stereo (40ms 1kHz burst 1% THD) (2 ohm load)
  • Class A/B circuit with switch-mode power supply
  • Variable speed fan cooled


Controls & features2 x illuminated volume, Stereo / parallel / Bridge mode switch, Sensitivity Switch, Hi Pass filter switch, illuminated logo
CoolingVariable speed fan cooled
Damping Factor>200 (8 ohm stereo, 1kHz)
DesignClass A/B circuit with switch-mode power supply
Dynamic Range>80dB
Frequency Response20Hz - 20kHz +/- 0.25dB
IndicatorsPower, Signal, Clip, Mode, Protect (ch1 & ch2)
Input ImpedanceBalanced 20K, unbalanced 10K
Input Sensitivity26dB/32dB (2.48V/1.244V)
Product Type2U Rackmount Power Amplifier
ProtectionTemperature, short circuit, DC, VHF, low power, Clip
Rated Power 2 Ohm2 x 600W stereo (40ms 1kHz burst 1% THD) (2 ohm)
Rated Power 4 Ohm2 x 450W stereo EIA standard. 1200W Bridged (40ms 1kHz burst 1% THD) (4 ohm)
Rated Power 8 Ohm2 x 310W stereo, 900W Bridged (EIA standard) (8 ohm)
S/N Ratio>90dB
Signal connections2 x Balanced XLR/jack combi inputs, XLR link outputs
Slew Rate20V/ms (8 ohm stereo, 1kHz)
Speaker Connections2 x speakon socket & 2 pairs Binding Posts
THD + N<0.05% (8 ohm stereo, 1/4 rated power, 1kHz)
Voltage Gain26dB/32dB
Mains LeadIEC
Dimensions (HxWxD) (mm)89 x 483 x 445mm (2U 19") (3.5 x 19 x 19.5 inch)
Packed Volume0.051m3 (1.8 cu. Ft)


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