Z10e Electrostatic Ampli9ier User Guide
transformers operating at a constant RF carrier frequency of 250kHz. Because the
audio signal is riding on a carrier, it is not subject to parasitic elements of the
transformer that would distort the audio signal. Unlike the conventional audio-
output transformer, this impedance transformation operates on both the ac and dc
components of the signal.
In the transformer-coupled ampli9ier, the turns ratio of the output transformer
determines the impedance matching between the output tube(s) and the speaker.
With output transformers, there are practical limits to how large this ratio can be
made because of the parasitic elements of the windings, and it is dif9icult to make an
output transformer with more than a 25:1 ratio.
With the ZOTL technology, the impedance matching is determined by the effective
turns ratio of the RF converter transformers (called impedance converters). Without
the parasitics to affect the audio, these impedance converters can have much higher
effective ratios, opening the door to using various tubes under unusual operating
conditions that cannot be implemented with output transformers.
9
Linear Tube Audio
