Overview

The FiiO K15 is a desktop DAC, headphone amplifier and network streamer in one chassis, built around two AKM AK4497S DAC chips on a fully differential circuit. It's for listeners who want a single box that can play music from the network, a computer, a phone or an analog source, and drive anything from sensitive in-ear monitors to demanding full-size headphones, with line outputs for powered speakers or a separate amp.

The whole audio path, from DAC and low-pass filter to gain control and headphone amp, is fully differential. The headphone stage is a discrete Class-AB design using an op-amp with ON Semiconductor MJE243G/253G transistor pairs for current, delivering up to 3000mW per channel into 32 ohms from the 4.4mm and XLR4 balanced outputs and 1400mW from the 6.35mm output, with five gain levels. Power, digital and analog sections sit on physically separate boards, fed by a built-in 30W low-noise supply and up to 14 low-dropout regulators in the analog section, and two Accusilicon femtosecond oscillators handle clocking. A 12V DC input lets you add an external linear supply.

The K15 has eight working modes: USB (up to 768kHz/32-bit and native DSD512), coaxial, optical, RCA line in, 4.4mm balanced line in, Bluetooth 5.1 with LDAC and aptX Adaptive, network streaming and local playback from a USB drive. On the network side it has Gigabit Ethernet and dual-band Wi-Fi, and FiiO documents AirPlay and Roon Ready streaming. A 10-band PEQ works on every digital input, set through the FiiO Control app or FiiO's web tool, and a 3.93-inch touch display, five knobs, an IR remote and full MQA decoding round it out.

Simcoe Audio Video Insight

FiiO notes that the 6.35mm, 4.4mm and XLR4 outputs are all live at the same time, so unplug your full-size headphones before plugging in IEMs, and check the gain and volume first, since a setting meant for big headphones can be far too loud for sensitive in-ears. The analog line inputs bypass the PEQ, so set your tone from a digital source. For network streaming, a wired Ethernet connection is the most dependable choice when your router is within reach.

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Why the FiiO K15 Stands Out

Buyer's Guide

Who It's For

• The All-In-One Desk Builder: Wants streamer, DAC and amp in one box.
• The Full-Size Headphone Owner: Needs up to 3000mW balanced.
• The Roon or AirPlay User: Wants to stream without a computer attached.

How It Compares

Compared with the FiiO K13 R2R, the K15 uses dual AKM delta-sigma DACs rather than an R2R ladder, adds Gigabit Ethernet, Wi-Fi, AirPlay and Roon Ready streaming, analog line inputs, local USB-drive playback and an XLR4 headphone output, and raises balanced power from 2400mW to 3000mW, in a larger chassis.