Used items in Headphone amplifiers

FiiO K11 R2R

Display, gain switch, USB-DAC

Fosi Audio K7

Display, Tone control, Bluetooth

FiiO KA11

iFi Audio GO link 2

USB-DAC

FiiO KA13

gain switch, USB-DAC

FiiO K13 R2R

Display, gain switch, Tone control, USB-DAC, Bluetooth

Fosi Audio K5 Pro

Bass Boost

iFi Audio GO link 2 Max

USB-DAC

FiiO K11

Display, gain switch, USB-DAC

FiiO K7

gain switch, USB-DAC

FiiO JA11

USB-DAC

FiiO Jiezi B

Tone control, USB-DAC

FiiO Jiezi A

Tone control, USB-DAC

FiiO Jiezi A

Tone control, USB-DAC

FiiO BTR17

Display, Microphones, Tone control, USB-DAC, Bluetooth