LZ SEVEN - Our "tube amp replacement" MOS-FET power amp design

Seven - this name is an indicator of a long time project, this is the seventh stage of it's development. This project has been started as a research in 1997 at the time of Zeppelin Audio (our former audio distributor company) while we wanted to develop an organic sounding amplifier to drive KEF Reference loudspeakers. It has taken 5 years of heavy work until we succeeded to finalize fundamentals of this design to reach the goals, smooth, organic sound with sufficient power. The "LZ" project as we say, later turned into realizatioan interesting target: we wanted to make a "sonic hybrid" amp. One that has all the positive sonic attributes of tube sound, the smoothness, the warmth, the rich tonal character, the unfatiguing nature AND all the positive technical elements of a good solid state amplifier, the high power, the wide bandwidth, very low distortion and long lifetime without any maintenance, costly tube changes or repetitive bias resettings. The low power consumption (ie. lack of tube heating) is extra addition.

LZ Project - Zeppelin airships' original factory serial numbers were began with LZ ( Luftschiff Zeppelin). For example airship Graf Zeppelin was LZ-127 by factory number. Few people knows, and we wanted to respect on to this, original idea and first design of airships was an invention of a Hungarian man named David Schwartz whose widow sold his invention to Graf Zeppelin. Airships were unique invention at their time, something similar to our LZ project: marriage of tube and transistor advantages while avoiding their disadvantages. Yes, we did it.

Technical details:

Description: Class AB MOS-FET stereo power amplifier

Power output:                 150W /channel into 4 Ohm ( 110 W /channel into 8 Ohm and 80 W / channel into 2 Ohm )

Frequency range:           1 Hz - 75 kHz (+/- 3 dB)

Output Noise:                 2 mV

Harmonic distortion:      <0,02% ( 3rd harmonic )

Intermodulation:             <0,005%

Phase linearity:                <5 deg. between 100 Hz and 10 kHz

Power consumption:       25 W idle, 330 W full power. 230V 50Hz

Input terminals:               RCA

Output terminals:           Banana and bare wire ( max.dia 6 mm )

Weight:                           10,6 kg (20 lb)

Warranty:                         5 years