The Pro iESL series - the best way to control electrostatic headphones.
The iESL Pro, paired with the iCAN Pro or your existing amplifier, can rightfully be considered the best amplifiers for electrostatic headphones. Its defining characteristic is an ultra-wide dynamic range that provides transparency and naturalness of sound.
Imagine that your electrostatic headphones are like a Porsche. The Porsche engine requires much more power than your standard car. And so it is with electrostatic headphones! They need to be "charged" or, more accurately, "under voltage".
Traditional amplifiers do not provide EHT (extra-high tension) voltage or the required sound voltage needed for electrostatic headphones. To "excite" the electrostatic plates in the headphones, a special "energizer" is required, with a maximum output of 300V!
The Pro iESL uses 3 main components, designed using the best classical approaches combined with the latest advanced technologies, to provide perfect compatibility with the headphones.
- Custom Pinstripe Permalloy Core Transformer - One per channel
- Bias Voltage Generator
- Capacitor Bank
Pinstripe Permalloy Core Transformer (PPCT)
Creating a transformer with an ultra-wide bandwidth and low distortion, necessary in the iESL, is very challenging. To achieve this, the transformers use complex hand-wound, multi-section windings with vertical and horizontal separation. They exceed the standards set by Siemans (Germany) and Peerless (USA). With a frequency response from <5 Hz to >60 kHz (-3 dB), the transformers in the iESL far exceed even the JAS High-Res logo requirements.
Capacitor Power Bank
They are charged to the required voltage and then the charging circuit is completely disconnected, leaving the capacitor bank "floating" at the required bias voltage. Essentially, it is an ideal bias voltage source without any electronic noise at any frequency, as the headphones are essentially powered by a battery, not the grid!
Wima Capacitors
Another high-quality component, ideal for the capacitor power bank. These 1000V-rated capacitors are made in Germany. Their advantage is very high insulation resistance and minimal leakage current, as any such leakage causes self-discharge. The entire capacitor's insulation resistance is around 35,000,000 kΩ, meaning the self-discharge time (to 30%) is around 100,000 seconds or 27 hours. You will always be able to enjoy music using high-quality battery-powered (not grid-powered) supply.
High-Precision Vishay MELF Resistors
Vishay MELF provides superior SMD resistor characteristics in terms of accuracy, stability, reliability, and pulse load capability. The cylindrical construction of MELF devices ensures optimal power and pulse load requirements for the iESL. MELF resistors are more complex and therefore more expensive. When assembling PCBs, MELF resistors require special machines and processing, but at iFi, we do not shy away from such complexities if it means higher quality components.
Take your dynamic headphones to new heights
The unique properties of the transformer bring the iESL to a new, unparalleled level of sound. As a result, flagship dynamic headphones, when used with the iESL amplifier, possess a completely new level of detail and airiness.