HPEL Drive Electronics

A sound reproduction system is only as good as its weakest link. For this reason, Warwick Audio Technologies has designed HPEL proprietary drive electronics to meet two goals:

  1. To reproduce Hi-ResTM Audio without degradation or compromise – ensuring that the electronic circuitry has superior audio performance in terms of wide bandwidth and dynamic range, low noise and distortion, and requisite time domain fidelity.
  2. To energise and power the HPEL transducer in the most ideal manner, fully optimised for the reactive load impedance over the entire operating range.

Driving the HPEL transducer effectively requires highly specialized electronic circuitry that will achieve two purposes:

  1. to provide a high charge voltage or bias, of 1350 VDC and,
  2. to amplify the audio signal to high voltages – as high as 425 Vpeak – over the full operating range and load impedence variation of the HPEL.

The electrostatic drive principal upon which the HPEL transducer is based requires a high DC voltage to be applied to the diaphragm to establish an adequate static charge (aka, “energising”). This charge forms the basis for the electrostatic force that will move the diaphragm.

The HPEL transducer presents a reactive load impedance that is quite unlike standard electrodynamic and planar magnet transducers – the impedance increases in capacitance as frequency increases, approaching a purely capacitive load at high frequencies (especially above 20 kHz). This means that the AC amplification circuitry must be able to drive very high voltage swings at low frequencies and deliver high current at high frequencies. Our circuitry can drive the HPEL transducer with over 145 Vrms without clipping or distorting, even at higher frequencies, where the load approaches a dead short (0 Ω).

These drive requirements are implemented in best-in-class operational topologies for audio reproduction. To ensure the highest level of performance, our drive electronics utilize discrete transistor output stages and the finest passive components.

Warwick Audio Technologies’ HPEL Drive Electronics are available in various configurations to address portable, mobile and low power applications as well as stand-alone, at-home and in-studio use.