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iFi audio Pro Series iESL Transformer (Coupled Energizer)

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iFi audio Pro Series iESL Transformer (Coupled Energizer)
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iFi audio 301003 Overview

  • 1Description
  • 2Pinstripe Permalloy Core Transformer
  • 3Capacitive Battery Power Supply
  • 4Wima Capacitors
  • 5Vishay MELF resistors
  • 6Gold-Plated Silver Contact Relays
  • 7Sealed-Silver Alloy Contact Relays

The Pro Series iESL Transformer from iFi AUDIO offers transparency and an ultra-wide range. It works with all Stax, Sennheiser Orpheus, and electrostatic headphones.

Pinstripe Permalloy Core Transformer

The high-bandwidth transformer uses complicated hand-wound, multi-section on windings with both vertical and horizontal sectioning. With a bandwidth of < 5 Hz to > 60 kHz (-3 dB), transformers in the iESL exceed the requirements.

Capacitive Battery Power Supply

Charged up to the required voltage with the charger circuit then turned off completely, the capacitor bank floats at the required bias voltage. A suitable bias voltage source with no electronic noise at any frequency. Listening is via battery (not main) power.

Wima Capacitors

These 1000V rated capacitors have very high insulation resistance and minimal current leakage. Any leakage causes self-discharge. The whole capacitor pack has around 35,000,000 kOhms insulation resistance, which means that self-discharge time (to 30%) is around 100,000 seconds or 27 hours.

Vishay MELF resistors

MELFs offer SMD resistor performance in terms of accuracy, stability, reliability, and pulse load capability. The cylindrical construction of MELF devices provides the optimal power rating and pulse load capability needed for the iESL.

Gold-Plated Silver Contact Relays

The entire signal switching for the input selection utilizes gold-plated silver contact miniature relays, filled with an inert gas.

Sealed-Silver Alloy Contact Relays

The speaker connections are switched using sealed silver alloy contact relays for minimum impact on the sound quality of the speaker path.

iFi audio 301003 Specs

Form FactorTabletop
Number of Headphone ChannelsSingle Channel
Frequency Response5 Hz to 50 kHz -3 dB
Max Output Level640 Vrms (16-Ohm Load)
320 Vrms (64-Ohm Load)
DC Input Power5 to 9 VDC at 1A
Power Consumption1 W
Dimensions8.4 x 8.1 x 2.5" / 213 x 206 x 63.3 mm
Weight5.5 lb / 2.5 kg

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