The Porsche and the Pro
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.

Big sound
If you like electrostatics, then you like ‘big’ sound.
The Pro iESL won’t disappoint. Coupled with our more traditional flagship amplifier, the Pro iCAN (or any other, but we like ours), the Pro iESL lowers distortion, separates vocals, orchestras and instruments.
It opens up the bass and leaves you with a wide, structured soundstage.
Dynamic duo
And, we’ve got good news.
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.

Just go Pro
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.
Forget the Porsche – just go Pro.
The Sennheiser Orpheus HE90 are legendary headphones created in 1991 and limited to 300 pairs. They came with their very own valve amp and cost $16,000. Phew!
Founded way back in 1958, Koss now produce a wide range of headphones to cater for varying tastes. One of their most acclaimed creations is the ESP950, over electrostatic ear headphones which retailed at about $999.
When you see the Japan Audio Society (JAS) Hi-Res logo on a product it means that has this certification and conforms to the high standards for high resolution music put in place by the JAS consortium – to which the largest global electronics manufacturers and the biggest music labels have all subscribed.