Power Input105-125 Volts (AC)
Power Output20 watts into 8Ω (mono)
Speaker TerminalsScrew Type
Frequency response15Hz to 30kHz
Total harmonic distortion1%
Signal to noise ratio90dB
Speaker load impedance8Ω or 16Ω
Tube Complement7: 12AU7, 12AT7, 12AX7 (2), EL84 (2), 6CA4
Dimensions12"w x 4"h x 11"d
60 seconds. That's all it takes to create a complete stereo electronic center with the new Harmon-Kardon Nocturne, Model AX20. To convert your present system – component or console – to stereo, simply plug the AX20 into your present amplifier. This one connection does it all.
With the a X 20 there's no shuttling back-and-forth between two different instruments (you can even touch your present amplifier out of sight); no adapter box to complicate matters. This one unit – the AX20 – controls the power to both amplifiers. It also controls treble, bass, volume, contour, balancing, and equalization for both.
The AX20, in brushed copper and black, is strikingly handsome in appearance and outstanding in its performance characteristics. The amplifier delivers 20 watts of hum-free, distortion-free power (40 watt peaks). An exclusive new high-gain phase inverter, utilizing both positive and negative feedback, drives the output tubes with minimum phase shift and excellent stability. As a result, the power amplifier has instantaneous recovery time resulting in uniquely clean and faithful transient response. The AX20 actually produces more clean, useful power than conventional 30 watt amplifiers.
The preamplifier is a dual stereo device incorporating ganged bass and treble tone controls, loudness control, contour control, rumble filter, balance control, mode switch, speaker selection, and function switches. Selectable equalization is provided for records and tapes. The second preamplifier delivers half volt output at low impedance.