Krell Illusion II Preamplifier

The Illusion II is the perfect centerpiece for a world class digital and analog audio system. Added to the normal selection of balanced and single- ended inputs are five digital inputs. The digital module features AES/EBU, coaxial, and optical digital inputs for use with streaming devices or other digital sources.

• Circuitry Highlights

The Illusion II preamplifier is a dual monaural design with the left and right channels afforded their own power supply regulation and individual circuit boards. All signal gain is executed with surface mount technology using proprietary multiple-output current mirrors with nearly 500 times the open loop linearity of other designs. Featuring 700 kHz bandwidth in a zero feedback, balanced, Krell Current Mode design, the Illusion II shares the same design philosophy as its bigger brother, the flagship Illusion preamplifier. Negative feedback is not used anywhere in the preamp, nor is it necessary. Open-loop distortion is typically less than 0.003%. The volume control is realized with a balanced resistor ladder – bandwidth and transient response of the preamp circuitry are virtually unaffected by the volume setting. The headphone circuitry is identical to the main circuitry, offering private listening with the same performance as speaker playback.

• Digital Module Highlights

The digital module supports up to 24 bit/192kHz LPCM. All digital signals are fed to an ESS Sabre DAC and then sent to Krell’s Current Mode, discrete, balanced analog circuitry.

• Power Supply Highlights

Oversized for a preamplifier, the power supply features a 95 VA transformer  and 40,000 µF of capacitance giving it the ability to respond quickly to musical demands. The large power supply improves noise rejection and renders the Illusion II impervious to all but the most severe AC voltage power fluctuations. A new eco-friendly standby mode reduces power consumption to 2W.

TECHNICAL SPECIFICATIONS

• Analog Inputs
• 2 pr. balanced via XLR connectors
• 3 pr. single-ended via RCA connectors
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• Digital Inputs
• 1 AES/EBU via XLR connector
• 2 coaxial via RCA connectors
• 2 optical via Toslink connectors
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• Main outputs
• 1 pr. balanced via XLR connectors
• 1 pr. single-ended via RCA connectors
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• Headphone output
• 1 via 3-conductor 6.35 mm (1/4 inch) connector
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• Control inputs
• 1 RS-232 input via a 9-pin D-subminiature connector
• 1 remote IR detector input via a 3-conductor 3.5 mm connector
• 1 12 VDC trigger input via 2-conductor 3.5 mm connector
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• Control outputs
• 2 individually programmable 12 VDC trigger outputs via 2-conductor 3.5mm connectors (30 mA maximum per output)
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• Input impedance
• Balanced: 40kΩ
• Single-ended 20kΩ
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• Output impedance
• Balanced: 310 Ω
• Single-ended: 155 Ω
• Headphone: <3.0Ω
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• Frequency response
• 20 Hz to 20 kHz +0, -0.02 dB
• 0.25 Hz to 1.2 MHz +0, -3 dB
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• Total harmonic distortion plus noise
• Balanced Output: <0.003%, 20 Hz to 20 kHz, at 4.0 V RMS
• Headphone: <0.09%, 20 Hz to 20 kHz, 2.0 V RMS, 32 Ω load
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• Gain
• Balanced: 12.0 dB
• 6 dB (single-ended output)
• Single-ended: 6.0 dB
• Headphone: 5.1 dB with 32 Ω load
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• Volume control
• Current mode, 12-bit, discrete R-2R ladder
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• Input overload
• > 7.0 V RMS balanced or single-ended
• Krell Illusion II Preamplifier Front
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• Output overload
• Balanced: >16 V RMS
• Single-ended: >8.0 V RMS
• Headphone: >3.0 V RMS, 32 Ω load
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• Signal-to-noise ratio
• 100 dB wideband, unweighted
• 107 dB ”A”-weighted, both referred to 4.0 V RMS balanced
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• Power consumption
• Standby: <2 Watts
• Power on: 40 Watts
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• Dimensions
• Preamplifier only:
• 17.3 in.W x 3.8 in. H x 18.3 in. D
• 43.8 cm W x 9.7 cm H x 46.4 cm D
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• Weight
• Shipped: 38 lbs., 17.2 kg
• Preamplifier only: 23 lbs., 10.4 kg