Reviews and Awards

Home Theater Review

"Branded sound systems are often gimmicks that allow automakers to charge more for equipment from renowned names in audio. Unfortunately, most of them are fairly disappointing. Take the $6300 Bang & Olufsen upgrade Audi offers, for example.

"But the Acura RLX premium sound system by Krell Industries lives up to the expectations of this enthusiast, making it one of the best factory sound systems I've tested. Acura doesn't charge much for the package, either; it's an extra $2500 if you were already leaning toward the technology bundle."

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Sound and Vision

"A great-sounding, reasonably priced analog two-channel integrated amp from a high-end brand that many people thought they would never be able to afford - and it's got an iPod interface, too"

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The Absolute Sound

"At 43 pounds, it outputs 150Wpc and doubles that rating into 4 ohms thus likely making the S-300i the most powerful amp in this price range."

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Downloads

S-300i

     - Product Manual

     - Tech Sheet

 

S-550i

     - Setup Guide

 

Vanguard

     - Setup Guide

Specifications

S-550i

Inputs

1 pr. balanced via XLR connectors

3 pr. single-ended via RCA connectors

1 dedicated iPod input via 30-pin connector

 

Outputs

1 pr. preamp outputs via RCA connectors

1 pr. speaker outputs via gold-plated binding posts

 

Control Inputs

1 RS-232 input via 9-pin D-subminiature connector

1 remote IR detector input via 3-conductor 3.5 mm connector

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

 

Control Output

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

 

Input Impedance

Balanced: 95 kΩ

Single-ended: 47.5 kΩ

 

Frequency Response

20 Hz to 20 kHz +0, -0.08 dB

<2 Hz to 140 kHz +0, -3 dB

 

Signal to Noise Ratio

>89 dB, wide band, unweighted, at maximum gain, referred to full power output

>96 dB, "A"-weighted

 

Gain

32.0 dB

 

Input Sensitivity

Single-ended or balanced: 1.18 V RMS

Total Harmonic Distortion

<0.025% at 1 kHz, at 275 W, 8 O load

<0.20% at 20 kHz, at 275 W, 8 O load

 

Output Power

275 W RMS per channel at 8 O

550 W RMS per channel at 4 O

 

Output Voltage

133 V peak to peak

47 V RMS

 

Output Current

20 A peak

 

Slew Rate

80 V/μs

 

Output Impedance

<0.073 Ω at 20 Hz

<0.08 Ω, 20 Hz to 20 kHz

 

Damping Factor

>110 at 20 Hz, referred to 8 O

>75, 20 Hz to 20 kHz, referred to 8 O

 

Power Consumption

Standby: 1 W

High-current standby: 40 W

Idle: 90 W

Maximum: 1800 W

 

Heat Output

Standby: 3.4 BTU/hr

High-current standby: 140 BTU/hr

Idle: 310 BTU/hr

Maximum: 2400 BTU/hr

Specifications for Preamp only:

 

Gain

6.3 dB (single-ended)

 

Volume Control

Current-mode, 12-bit, discrete R-2R ladder

 

Input Overload

Balanced: 12 V RMS

Single-ended: 6 V RMS

 

Output Overload

8 V RMS (single-ended)

 

Frequency Response

20 Hz to 20 kHz +0, -0.05 dB

<2 Hz to 1.0 MHz +0, -3 dB

 

Total Harmonic Distortion

<0.009%, 20 Hz to 20 kHz, at 2 V RMS

 

Signal to Noise Ratio

>87 dB, wide band, unweighted, at maximum gain, referred to 2 V RMS

>94 dB, "A"-weighted

 

Dimensions

17.26 in W x 5.84 in H x 17.70 in D

438 mm W x 148 mm H x 450 mm D

 

Weight

Unit only: 64 lb [29.0 kg]

As shipped: 76 lb [34.4 kg]

S-300i

Inputs

1 pr. balanced via XLR connectors

3 pr. single-ended via RCA connectors

1 dedicated iPod input via 30-pin connector

 

Outputs

1 pr. preamp outputs via RCA connectors

1 pr. speaker outputs via gold-plated binding posts

 

Control Inputs

1 RS-232 input via 9-pin D-subminiature connector

1 remote IR detector input via 3-conductor 3.5 mm connector

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

 

Control Output

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

 

Input Impedance

Balanced: 95 kΩ

Single-ended: 47.5 kΩ

 

Frequency Response

20 Hz to 20 kHz +0, -0.14 dB

<2 Hz to 140 kHz +0, -3 dB

 

Signal to Noise Ratio

>84 dB, wide band, unweighted, at maximum gain, referred to full power output

>93 dB, "A"-weighted

 

Gain

32.5 dB

 

Input Sensitivity

Single-ended or balanced: 800 mV RMS

Total Harmonic Distortion

<0.035% at 1 kHz, at 150 W, 8 O load

<0.26% at 20 kHz, at 150 W, 8 O load

 

Output Power

150 W RMS per channel at 8 O

300 W RMS per channel at 4 O

 

Output Voltage

99 V peak to peak

35 V RMS

 

Output Current

15 A peak

 

Slew Rate

50 V/μs

 

Output Impedance

<0.080Ω at 20 Hz

<0.11Ω, 20 Hz to 20 kHz

 

Damping Factor

>100 at 20 Hz, referred to 8 O

>75, 20 Hz to 20 kHz, referred to 8 O

 

Power Consumption

Standby: 40 W

Idle: 60 W

Maximum: 1000 W

 

Heat Output

Standby: 140 BTU/hr

Idle: 210 BTU/hr

Maximum: 1600 BTU/hr

Specifications for Preamp only:

 

Gain

6.3 dB (single-ended)

 

Volume Control

Current-mode, 12-bit, discrete R-2R ladder

 

Input Overload

Balanced: 12 V RMS

Single-ended: 6 V RMS

 

Output Overload

8 V RMS (single-ended)

 

Frequency Response

20 Hz to 20 kHz +0, -0.05 dB

<2 Hz to 1.0 MHz +0, -3 dB

 

Total Harmonic Distortion

<0.009%, 20 Hz to 20 kHz, at 2 V RMS

 

Signal to Noise Ratio

>85 dB, wide band, unweighted, at maximum gain, referred to 2 V RMS

>94 dB, "A"-weighted

 

Dimensions

17.26 in W x 4.09 in H x 17.70 in D

438 mm W x 104 mm H x 450 mm D

 

Weight

Unit only: 42 lb [19.0 kg]

As shipped: 51 lb [23.1 kg]