The S-150m is a slim line monaural power amplifier boasting our latest circuit topology and a substantial power output of 150 Watts into 8 Ohms and 300 Watts into 4 Ohms. The elegant exterior houses the technology developed in the Krell Evolution amplifiers including Krell Differential Current Mode circuitry and balanced operation. The S-150m is the ideal choice for high performance systems in space limited locations.

Power Supply
A linear power supply is employed in contrast to a soul robbing digital power supply employed in typical designs. An oversized 310VA toroidal transformer and 54,000 microfarads of filter capacitance make up the substantial power supply that is the engine of the S-150m.

Power output
Today's multi-channel music and movie soundtracks place tremendous stress on amplifiers. Each S-150m employs eight output devices to deliver the exact power required by the speakers under any demand. All speakers benefit from greater power, the more the better. The S-150M drives 150 Watts into 8 Ohms and 300 Watts into 4 Ohms.

Featuring circuitry sourced from the Evolution amplifiers, the S-150m includes technology previously incorporated in the reference level components only. The design is executed with Krell

Current Mode circuitry featuring balanced topology for the lowest noise and true insight into the recording. Class A input, pre-driver, and driver stages provide the most accurate signal path for critical low level signals. Surface mount technology is utilized for maximum circuit density resulting in the widest dynamic range and bandwidth possible. The amplifier circuitry also features very low negative feedback for improved clarity and detail resolution.

Each S-150m is only 3.4" wide allowing 5 S-150m amplifiers to fit in the same space normally occupied by a full size component. The S-150m includes 12V trigger input and output connections. High performance WBT speaker binding posts and input terminations complete the elegant rear panel.

Available in brushed aluminum silver and black finish

1 balanced via XLR connector
1 single-ended via RCA connector

1 pr. via WBT binding posts

Control input
1 12 VDC trigger input via 2-conductor 3.5 mm connector

Control output
1 12 VDC trigger output (30 mA maximum current) via 2-conductor 3.5 mm connector

Input impedance
20 kΩ (balanced or single-ended)

Frequency response
20 Hz to 20 kHz +0, -0.12 dB
0.3 Hz to 120 kHz +0, -3 dB

Signal-to-noise ratio
>109 dB, wideband, unweighted, referred to full power output
>119 dB, "A"-weighted

26.2 dB

Input sensitivity
Single-ended or balanced: 1.70 V RMS

Total harmonic distortion
<0.030% at 1 kHz, at 150 W, 8 Ω load
<0.20% at 20 kHz, at 150 W, 8 Ω load


Output power
150 W RMS per channel at 8 Ω
300 W RMS per channel at 4 Ω

Output voltage
99 V peak to peak
35 V RMS

Output current
17 A peak

Slew rate
50 V/μs

Output impedance
<0.070 Ω at 20 Hz
<0.080 Ω, 20 Hz to 20 kHz

Damping factor
>115 at 20 Hz, referred to 8 Ω
>100, 20 Hz to 20 kHz, referred to 8 Ω

Power consumption
Standby: 15 W
Idle: 30 W
Maximum: 550 W

Heat output
Standby: 50 BTU/hr
Idle: 100 BTU/hr
Maximum: 850 BTU/hr

3.40 in W x 5.66 in H x 21.90 in D
86 mm W x 144 mm H x 556 mm D

Unit only: 17 lb [7.7 kg]
As shipped: 21 lb [9.5 kg]



  • S-150 Mono Amplifier
  • S-150 Mono Amplifier
  • S-150 Mono Amplifier
  • S-150 Mono Amplifier
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