The FiiO K7 BT is a fully balanced desktop DAC and headphone amplifier for wired and wireless sources. Dual AK4493SEQ DACs and dual THX AAA 788+ amplifier modules provide up to 2000mW + 2000mW at 32Ω through the 4.4mm output, with a 6.35mm output for standard headphone cables.

Bluetooth 5.1 reception adds LDAC and aptX-family playback from phones and tablets, while USB, optical, coaxial and RCA inputs cover computers, televisions, disc transports and analog sources. Rear RCA output allows the K7 BT to serve active speakers or an external amplifier in fixed or variable mode.

Why it stands out

Dual AK4493SEQ balanced DAC architecture

Separate AKM converters for the left and right channels support a fully balanced signal path with a smooth, detailed presentation.

Dual THX AAA 788+ headphone amplification

The 4.4mm balanced output delivers up to 2000mW + 2000mW at 32Ω, while the 6.35mm output reaches 1220mW + 1220mW.

LDAC and aptX Adaptive Bluetooth reception

The Qualcomm QCC5124 platform supports LDAC, aptX Adaptive, aptX HD, aptX LL, aptX, AAC and SBC from compatible transmitting devices.

Five inputs and three practical output modes

Switch among Bluetooth, USB, optical, coaxial and RCA input, then choose PO for headphones, PRE for variable RCA output or LO for fixed RCA output.

Best for

• Desktop headphone systems using both wired and Bluetooth sources
• Balanced headphones with 4.4mm termination
• Computers, televisions and disc transports requiring one shared DAC
• Active speakers or amplifiers that need fixed or volume-controlled RCA output

Not ideal for

• Users who need Bluetooth transmission to wireless headphones
• Balanced speaker systems requiring XLR line output
• Portable or battery-powered listening
• Driving passive speakers without a separate speaker amplifier

EMiUZEK Buying Notes

• Bluetooth on the K7 BT is receive-only. It accepts audio from a phone, tablet or computer but cannot send audio to Bluetooth headphones or speakers.
• The 4.4mm socket is a balanced headphone output, not a balanced line output. Use the rear RCA connectors for an amplifier or active speakers.
• LO is fixed at line level and ignores the volume knob. Reduce the downstream system's volume before selecting LO; choose PRE when the K7 BT should control speaker volume.
• The K7 BT requires its 12V/2A external power adapter even when receiving audio by USB or Bluetooth. Confirm the correct regional power cable before use.

Frequently asked questions

What is the difference between the FiiO K7 BT and standard K7?

The audio architecture, wired inputs and outputs are otherwise substantially the same, but K7 BT adds Bluetooth 5.1 reception, a rear antenna and Bluetooth-related settings through FiiO Control.

Can the K7 BT transmit audio to Bluetooth headphones?

No. It is a Bluetooth receiver. Connect wired headphones to the 6.35mm or 4.4mm output.

Which Bluetooth codecs are supported?

It supports SBC, AAC, aptX, aptX LL, aptX HD, aptX Adaptive and LDAC. The source device must support and select the same codec.

How do I know which Bluetooth codec is active?

The K7 BT indicator and FiiO Control app do not display the active codec. Check the Bluetooth audio information on the transmitting phone, tablet or computer.

Can it connect to two Bluetooth sources?

Yes. Two devices can remain connected, but you must pause playback on one before starting the other; the K7 BT does not provide a hardware source-toggle between them.

What can FiiO Control adjust?

The app manages Bluetooth-related settings, codec selection, PEQ and Bluetooth firmware while the unit is in BT mode. It does not control every hardware input, RGB, sampling-rate or output function.

Can I use sensitive IEMs?

Yes. Select Low Gain, begin at minimum volume and increase gradually. The K7 BT is powerful, so high gain is unnecessary for most sensitive earphones.

What is the maximum balanced output?

FiiO specifies at least 2000mW + 2000mW at 32Ω and 560mW + 560mW at 300Ω from the 4.4mm balanced output under its stated test conditions.

What is the maximum 6.35mm output?

The single-ended output provides at least 1220mW + 1220mW at 32Ω and 140mW + 140mW at 300Ω under FiiO's stated conditions.

What do Low and High Gain change?

Low Gain is 0dB and High Gain is 6dB. Use Low Gain unless the headphone needs more volume range; gain has no effect in fixed LO mode.

Why is there no sound before the volume knob reaches about 9 o'clock?

The power switch and volume control share the same knob, with a designed low-level dead zone between Off and the usable volume range. This is normal behavior.

Can I connect active speakers?

Yes. Use the rear RCA output in PRE mode for variable volume or LO mode when the speaker or amplifier controls volume.

Can it drive passive speakers?

No. The RCA output is line level and requires an external speaker amplifier or powered speakers.

Can I use the 4.4mm output as a balanced line output?

No. It is a powered headphone output. Connecting it to a balanced amplifier input is not recommended; the K7 BT provides RCA line output only.

Does it have an analog input?

Yes. The rear RCA LINE IN bypasses digital conversion and allows the K7 BT to operate as a headphone amplifier for an analog source.

What is the difference between PO, PRE and LO?

PO activates the front headphone outputs with volume control. PRE activates variable rear RCA output. LO activates fixed-level rear RCA output.

What is the maximum USB decoding rate?

USB supports up to PCM 384kHz/32-bit and DSD256. Coaxial supports up to PCM 192kHz/24-bit, while optical supports up to PCM 96kHz/24-bit.

Does coaxial input support DSD?

FiiO's standard K7 BT specification lists PCM for coaxial input. Do not assume native DSD support over S/PDIF; use USB for documented DSD256 playback.

Does Windows require a driver?

Install the current FiiO USB DAC driver for full operation on Windows. Mac is driver-free; Linux compatibility depends on the distribution and USB audio implementation.

Can I connect a phone by USB?

Yes, with a compatible directional OTG cable to the USB-B input. Mobile USB audio support varies by device and app, and the required OTG cable is normally purchased separately.

Is it normal for the case to become warm?

Yes. The THX amplifier and internal circuitry generate heat during operation. Keep the ventilation area clear; protection circuits are provided for abnormal overheating, overload and DC output.

HOW TO CONNECT

Phone or tablet over Bluetooth

Source icon: Phone
Source: Smartphone / tablet
Connection: Bluetooth 5.1
Output connection: 6.35mm or 4.4mm headphone output
Target icon: Headphones
Output: Wired headphones or IEMs

Note: Select BT input and PO output. Bluetooth receives audio from the phone; it does not transmit to wireless headphones.

Computer to balanced headphones

Source icon: Computer
Source: Windows PC / Mac
Connection: USB-B data input
Output connection: 4.4mm balanced headphone output
Target icon: Headphones
Output: Balanced desktop headphone system

Note: Select USB and PO, install the FiiO driver on Windows, then start in Low Gain at a safe volume.

Television or digital transport

Source icon: TV or disc transport
Source: Optical or coaxial digital audio
Connection: TOSLINK optical / RCA coaxial
Output connection: 6.35mm or 4.4mm headphone output
Target icon: Headphones
Output: Personal TV or disc listening

Note: Set the source to compatible stereo PCM if necessary and match the K7 BT input to OPT or COAX.

Active speakers or stereo amplifier

Source icon: Digital or Bluetooth source
Source: USB / optical / coaxial / Bluetooth
Connection: Selected K7 BT input
Output connection: Rear RCA PRE or LO
Target icon: Active speakers or amplifier
Output: Stereo line-level system

Note: Use PRE for K7 BT volume control. Use LO only when the downstream component controls volume.

Technical Specifications

Feature	Specification
Product type	Bluetooth desktop DAC and balanced headphone amplifier
DAC	2 × AK4493SEQ
USB controller	XMOS XUF208
Headphone amplifier	2 × THX AAA 788+
Bluetooth	QCC5124; Bluetooth 5.1 receive-only
Bluetooth codecs	SBC, AAC, aptX, aptX LL, aptX HD, aptX Adaptive, LDAC
Inputs	Bluetooth, USB-B, optical, coaxial, stereo RCA line input
Headphone outputs	6.35mm single-ended; 4.4mm balanced
Line output	Stereo RCA, fixed LO or variable PRE
USB decoding	Up to PCM 384kHz/32-bit; DSD256
Coaxial decoding	Up to PCM 192kHz/24-bit
Optical decoding	Up to PCM 96kHz/24-bit
Balanced power	≥2000mW + 2000mW at 32Ω; ≥560mW + 560mW at 300Ω
Single-ended power	≥1220mW + 1220mW at 32Ω; ≥140mW + 140mW at 300Ω
Recommended headphone impedance	16–300Ω
Gain	Low 0dB / High 6dB
Line-output level	≥2Vrms
Power	DC 12V/2A
Dimensions	Approx. 120 × 168 × 55mm
Weight	Approx. 610g
Color	Black

What's in the box, manuals and downloads

• FiiO K7 BT ×1
• 12V/2A Power Adapter ×1
• Regional Power Cable ×1
• USB Data Cable ×1
• Bluetooth Antenna ×1
• Quick Start Guide ×1
• Warranty Card ×1

Visit the EMiUZEK download center.

Additional Product Content

FiiO K7 BT vs K7

Feature	K7 BT	K7
Bluetooth reception	Yes, Bluetooth 5.1	No
High-resolution wireless codecs	LDAC and aptX Adaptive supported	Not applicable
FiiO Control	Bluetooth settings and PEQ	Not supported
Wired DAC and amplifier architecture	Dual AK4493SEQ and dual THX AAA 788+	Dual AK4493SEQ and dual THX AAA 788+
Best reason to choose	Wireless source convenience	Lower-cost wired-only system