Imagine the audio equivalent of a Porsche engine of the flagship headphone world and you have the Pro iESL.Electrostatics need high voltages to energise them to make sound. The Pro iESL is one such energiser and delivers the extra-high-tension voltage needed. The capacitor pack has around 35,000,000 kOhm insulation resistance, which means that self-discharge time (to 30%) is around 100,000 seconds or 27 hours.It is one of the best energisers in the business (even if we do say so ourselves) and is compatible with all the great electrostatic brands – including Orpheus and Koss.

The Pro iESL can also be used with your flagship dynamic headphones thanks to a unique transformer-coupled-stage that can take them to the max.Enjoy the pure luxurious, pleasure of flying high with your headphones – electrostatics or dynamics – with the iFi Pro iESL.No more background noise, no more distortion. Just smooth, sexy, open audio.

Maximum Output voltage: 640V RMS (16Ω/20V in) 320V RMS (64Ω/20V in)
Frequency Response: 5Hz – 50kHz (-3dB)
Input Voltage (Pro iESL): 5V – 9V/1A max
Input Voltage (iPower): AC 85 – 265V, 50/60Hz
Power Consumption: < 1W
Dimensions: 213(l) x 206(w) x 63.3(h) mm
Weight: 2.5kg (5.5 lbs)