We'd like to present the KRELL Illusion Pre-Amp

It's....Perfect!

The Illusion preamplifier extends the Krell tradition of separating the power supply from the audio circuitry in their flagship preamplifiers. Sharing the new Class A iBias power amplifier aesthetic and featuring Krell CAST technology, the Illusion preamplifier is the ideal match for the new Solo 375 and Solo 575 power amplifiers.

The optional crossover functionality offers the ability to use a subwoofer/satellite speaker arrangement and still maintain the highest quality sonic performance. Previous to the Illusion preamplifier, this system configuration would require signals to pass through a subwoofer’s lower quality crossover circuitry. The Illusion preamplifier is the centrepiece of a world class audio system where space is at a premium. 

Crossover Highlights

Owing to Krell’s work in the Modulari Duo Reference loudspeaker, the unique crossover feature is a highly sophisticated option. When the optional board is present, additional crossover menu items become available.

 Definable parameters include independently assignable crossover frequencies and filter types for the high and low pass sections. Choices include 40Hz, 55Hz, 75Hz, and 100Hz crossover points with 12dB, 24dB, and 48dB Butterworth or 24dB Linkwitz-Riley style filters. The high pass section of the crossover uses the full Illusion preamplifier circuitry for its output stage.

Circuitry Highlights

The Illusion preamplifier is a dual monaural circuit design with the left and right channels afforded their own power supply regulation and individual full chassis-sized boards. All signal gain is realised in surface mount topology using proprietary multiple-output current mirrors with nearly 500 times the open loop linearity of other designs 1.5 MHz open loop bandwidth in a zero feedback, balanced, Krell Current Mode design terminating in Krell CAST.

 A complete Krell system (source, preamp, and amplifier) system, connected using CAST interconnects reduces the number of voltage gain stages to the minimum, one. The resulting noise floor approaches the theoretical limit of technology. 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 realised with a balanced resistor ladder—bandwidth and transient response of the preamp circuitry are virtually unaffected by the volume setting.

Power Supply

The Illusion audio circuits receive power from a Krell Current Mode analog power supply housed in its own dedicated chassis. The power supply avoids the common integrated circuit topology used in many preamplifiers and instead mimics the design topology of Krell Evolution e Series amplifiers.

The circuitry is completely discrete giving it the ability to respond quickly to current demands and also be unaffected by all but the most severe AC voltage power fluctuations.

Oversized for a preamplifier, the power supply features a 290 VA transformer and 41,600µF of capacitance. Locating the power supply in its own chassis presents the ideal configuration  for isolating stray electrical and magnetic interference from the critical preamplifier signal path.

Capable of delivering current and voltage swing for  any musical event, the Illusion power supply is gentle on AC requirements  when not in use whist the new eco-friendly design reduces standby power draw to 2W.

Technical Specifications

Inputs
2 pr. CAST via 4-pin bayonet connectors
2 pr. balanced via XLR connectors
3 pr. single-ended via RCA connectors

Tape input
1 pr. single-ended via RCA connector

Main outputs
2 pr. CAST via 4-pin bayonet connectors
1 pr. balanced via XLR connector
1 pr. single-ended via RCA connector

Subwoofer outputs
1 pr. balanced via XLR connector
1 pr. single-ended via RCA connector

Tape outputs
1 pr. single-ended via RCA connector ,buffered

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 3.5 mm connector
1 preamplifier link via an RJ-45 connector

Control outputs
2 individually programmable 12 VDC trigger outputs via 3.5 mm connectors
1 preamplifier link via an RJ-45 connector

Power output
1 phone power output (±20 VDC) for KPE via a 9-pin D-subminiature connector

Frequency response
20 Hz to 20 kHz ± 0.02 dB
0.35 Hz to 720 KHz +0, -3 dB
Single-ended: 8 V RMS

Total harmonic distortion plus noise
Balanced Output: <0.003%, 20 Hz to 20 kHz, 4 V RMS or 4mARMS

Input impedance
CAST: 25 Ohms
Balanced: 40 k Ohms
Single-ended: 20 k Ohms

Output impedance
CAST: >1 MΩ
Balanced: 250Ω
Single-ended: 125Ω

Gain
12 dB (CAST or balanced output)
6 dB (single-ended output)

Volume control
Balanced, current-mode, 16-bit, discrete R-2R ladder

Input overload
Balanced, current-mode, 16-bit, discrete R-2R ladder

Output overload
CAST: 16 rnA RMS
Balanced: 16 V RMS
Single-ended: 8 V RMS

Signal-to-noise ratio
4 V RMS balanced or 4 mA RMS CAST output
Wideband, unweighted: >100 dB
“N’ weighted: >109 dB

Power consumption
Standby: 60 W
Power on: 65 W
Power on, with KPE: 75 W

Dimensions (W x H x D)
Preamplifier  - 438 x 97 x464 mm
Power supply - 438 x 97 x448 mm
Preamplifier and power - 438 x 192 x 464 mm

Weight
Preamplifier - 8.1 kg
Power supply -12.7 kg

*This information has been obtained from Manufacturers website. We advise that Price, Features & Specifications are subject change without notice.