FiiO IMP XLR-4 manages speaker amplifier output for compatible headphones

The FiiO IMP XLR-4 is a headphone impedance adapter designed to connect compatible headphones directly to the speaker outputs of a home HiFi power amplifier. Its internal voltage divider circuit attenuates the amplifier’s higher output before the signal reaches the headphones while also helping reduce residual amplifier noise. Designed for headphones with impedances from 16 to 300 ohms and compatible power amplifiers rated below 300W, the IMP XLR-4 provides balanced 4.4 mm and 4-pin XLR headphone outputs for driving high-impedance or low-sensitivity headphones from suitable speaker amplifiers.

Using a power amplifier with headphones

Power amplifiers are designed to deliver substantially more voltage and current than a typical headphone amplifier, so connecting headphones directly to speaker terminals requires controlled attenuation. The IMP XLR-4 sits between the amplifier and headphones, accepting the amplifier’s speaker-level output through four 4 mm banana jack inputs and reducing that output to a level suitable for compatible headphones.

The adapter supports headphones with impedances from 16 to 300 ohms and is intended for use with compatible amplifiers producing less than 300W. This arrangement gives demanding headphones access to the available drive capability of a speaker amplifier while controlling the higher output level before it reaches the headphone connection.

Internal voltage divider circuit

Inside the IMP XLR-4, a voltage divider circuit reduces the amplifier output before passing the signal to the headphones. The same attenuation also lowers the level of residual amplifier noise reaching the headphone output, which is especially relevant when pairing a high-output speaker amplifier with lower-impedance or higher-sensitivity headphones.

Because the adapter is connected to a power amplifier capable of significantly higher output than a conventional headphone amplifier, FiiO recommends lowering the amplifier level before listening and then increasing volume gradually to the required level.

Balanced 4.4 mm and 4-pin XLR outputs

The IMP XLR-4 provides two balanced headphone connections directly on the enclosure: a 4.4 mm output and a 4-pin XLR output. Both connector types are commonly used with balanced headphone cables, allowing compatible headphones to connect without adding another format-conversion adapter between the IMP XLR-4 and the cable.

Gold-plated copper amplifier connections

Four 4 mm banana jack inputs connect the IMP XLR-4 to the power amplifier’s speaker outputs. The binding posts use copper conductors with gold plating, providing a stable electrical contact while helping protect the contact surfaces against moisture, corrosion, and oxidation over repeated connections.

Aluminum alloy enclosure

The adapter is housed in a high-density aluminum alloy enclosure. The metal chassis provides physical shielding against electromagnetic interference while also conducting heat away from the internal assembly during operation. Its compact dimensions allow it to sit alongside a desktop or home HiFi power amplifier without requiring a separate headphone amplification stage.

Availability

The FiiO IMP XLR-4 power amplifier impedance adapter is available at apos.audio.