The LISZT power amplifier (mono-mode: 200W @ 8Ω ; stereo-mode: 55W @ 8Ω) brings together apparently conflicting attributes like, operating speed, current drive capability, stability in any load, lowest distortion and ultra low noise to name but a few. A key ingredient in achieving this difficult task is the fully symmetric operation from input to output and the high speed signal processing. It is the fast transient ability and ultra wide bandwidth (1.2MHz unfiltered) approach that let you hear the room, the ambience of the sound recording. Matching phase coherent speakers assumed, a (pair of) LISZT amplifier(s) will deliver a perfectly executed soundstage.

Ultra wideband design

The high quiescent current design of all preamp and driver stages enables a core speed close to 1.2MHz, slowed down only by input and output filtering to match real word requirements. With filters in place, the small signal as well as full power bandwidth (!) measures an impressive 400 kHz. The lower frequency limit is around 0.3 Hz. No coupling capacitors are used throughout.

Inherently low noise

High resolution audio is intrinsically tied to low noise and low distortion. System noise is the lower resolution limit of an analog system, because it determines the smallest signal not masked by a noise floor. Hence, low noise levels and thus a wide dynamic range are desirable. A-weighted output noise measures 40V for the LISZT giving a SNR of 122dB or an equivalent to 20bit. 20 to 21 bits analog resolution is the realistic limit, dictated by the laws of physics.

Lateral MOSFET output stage

The lateral MOSFET transistor originally developed by Hitachi in the late 70’s is probably the only semiconductor power device solely made for audio use. Famous for its tube like characteristic and perfect bias stability under any load conditions, the LISZT uses a single pair of tandem devices in each output stage. The output transistors are energized by a heavy duty toroidal transformer running a bank of 120.000F storage capacitors.