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Small silver desktop headphone amplifier with 6.35mm and 3.5mm jacks and RCA inputs

BFKK

BFKK U3 Headphone Amplifier 6.35mm 3.5mm RCA Class A DC 5V

SKU CH-S58A-DE3GN

Compact Class A headphone amplifier with 6.35 mm, 3.5 mm and RCA connections, DC 5 V power, TI NE5532 op-amp socket and 1300 mA output transistors for warm, detailed sound

  • Class A 1300 mA output stage delivers warm, detailed sound
  • TI NE5532 op-amp socket allows easy rolling for custom tone
  • 5 – 20 V DC input maintains 26 V rail for ultra-low noise
  • 35 mm and 3.5 mm jacks drive HD600, DT880, K701 and more
  • RCA input integrates with desktop or home hi-fi systems

Compact desktop headphone amplifier

The BFKK U3 is a mini Class A headphone amplifier designed for home or office desktop use. It accepts a DC 5 V supply and operates with a wide 5‑20 V input range while the internal circuit runs at 26 V. The unit provides both 6.35 mm and 3.5 mm headphone outputs plus RCA inputs for simple system integration.

Thermals noise and power

The amplifier uses an original TI‑NE5532 op‑amp paired with a transistor current‑expansion stage biased at 1300 mA in Class A, delivering ultra‑low distortion and a warm, detailed sound signature. Background noise remains very low across the extended frequency response, and the wide‑voltage input design keeps the circuit stable without audible hum during normal listening sessions.

Swappable op‑amp socket and drive capability

A pluggable op‑amp socket lets enthusiasts swap the stock NE5532 for alternative devices, adding DIY flexibility and tonal variety. The strong output stage easily drives high‑impedance models such as the HD580, HD600, HD650, K701, K702, Q701, DT880, T70, T90, SR225, SR325 and RS1e, providing ample power, wide soundstage and fine detail for critical listening.

Highlights

  • Class A 1300 mA output stage delivers warm, detailed sound
  • TI NE5532 op-amp socket allows easy rolling for custom tone
  • 5 – 20 V DC input maintains 26 V rail for ultra-low noise
  • 35 mm and 3.5 mm jacks drive HD600, DT880, K701 and more
  • RCA input integrates with desktop or home hi-fi systems

Specifications

No published specifications for this item yet.

Questions about this item

How do I connect the BFKK U3 amplifier to my headphones and source using the 6.35mm, 3.5mm and RCA ports?

Plug your source into the RCA inputs, then connect your headphones to either the 6.35mm or 3.5mm output jack. Power the unit via the DC 5V input. Ensure the op amp is firmly seated in its socket before powering on.

What maintenance does the pluggable TI-NE5532 op amp socket require over time?

The socket allows you to swap op amps for different sound signatures. If contacts oxidise, gently reseat the NE5532 or a compatible replacement. No soldering is needed, but handle pins carefully to avoid bending them during upgrades.

At what point does the 1300mA Class A output stage hit its thermal limit during extended listening?

Running in pure Class A at 26V internal rail voltage, the output transistors draw constant current. Under sustained high-volume use with demanding loads like 300-ohm headphones, the chassis becomes the heatsink; expect warmth after 30-60 minutes.

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