Bluebird U3 Mini

General Information

- Aluminum brushed shell
- 2380MA lithium battery

User Interfaces:
• Input: 3.5mm mini-jack audio input
• Output: 3.5mm mini-jack audio output
• Charging input: Android USB universal phone charge port
• Switch: Power switcher
• Volume control knob

Parameters :
(roughly estimated power output: 100mW @ 32 ohms)
• Impedance headphones supported : 12-300ohm
• Frequency Response: 13Hz - 23kH
• Battery volume : 2380MA
• Dimension: 11*6*1.4cm(including the knob)
• Net weight: 0.1kg
• Color options: Black or Red

Product package include:
• 1 x U3 MINI portable Amplifier
• 1 x 3.5mm to 3.5mm jack audio cable
• 1 x Bundle tapes
• 1 x Rechargeable Lithium battery 2380MA(inside)
• 1 x OPA2604AP op-amp chip(inside)

Latest reviews


New Head-Fier
Pros: Aluminum brushed casing, Battery Life, Sound Quality, Price
Cons: Audible buzz if using while charging, rattled when shook (read review)
Hello fellow head-fi-ers!
This is actually my first review, so I'll try my best to give you guys some quick honest feedback on this product.


  1. brushed aluminum feels and looks nice, making for a good balance between value and looks
  2. seems to be rather durable, have only dropped it once (from a decent distance), and not a scratch/dent was made
  3. volume knob isn't very loose, and jacks feel sturdy and secure
  4. size is very nice, roughly equivalent to an iPod Touch 4G (slightly thicker though)
  5. if used while charging, there is a loud buzz
  6. 3.5mm cable that came with the amp is gold plated and thick!
  7. battery life seems to be pretty great! (have used it on and off the past 2 weeks, and still haven't had to charge it)
  8. power output ROUGHLY: ~80-100mW @ 32 ohms (with my DT770's: ~32-40mW @ 80 ohms)
When I first received this amp from aliexpress, one of the first things I noticed after I took it out of the packaging was a slight rattle when shook. I decided to investigate, taking apart the amp, and the only thing I could make out that was rattling was either the battery or the wires connecting to the battery (see below pic). Really didn't do much adjusting at all, just a little nudge to the wires and the battery, and, after putting it back together, the rattle was gone!

Sound Quality

  1. better than expected, was rather skeptical before purchasing
  2. nice, smooth lows, doesn't seem to modify their sound very much at all
  3. the lower mids are a little more pronounced, while the upper mids and highs seem to be negligibly affected
  4. great for the price!
On aliexpress and elsewhere, the U3 Mini is advertised as having a warm sound, but from what I have experienced so far, it really seems to be more of a warm-ISH sound. Yes, it is not bright, but I would not say that it is very warm either.


Would recommend this product if you are looking for a portable amp in this price range! Design and sound are very nice, and for only ~$35, you can get a decent amp to power your cans!
alexandros a
alexandros a
HEY just got bluebird U3.6 and i am amazed and astonished by the sound quality and the soundstage with the original op amp
Anyway i also ordered with that muses02 chip to upgrade original amp but till now seems very hard to unscrew one of the four screws in the upper surface of bluebird close to the volume knob....
Tried any kind of screwdrivers but that screw cant be rotated no matter how hard i have tried...
Any ideas?