Little Bear B4 Portable Vacuum & Valve Tube Headphone

Little Bear B4 Portable Vacuum & Valve Tube Headphone Amplifier HiFi for Phone
- B4 is a very special portable vacuum tube headphone amp that you can hardly see on the market. Our technicians made much efforts to eliminate interference that may exist due to its portable design.
- Adopts dual USA 5899 tubes and NE5532 OP chip (replaceable), which can provide really warm and classic tube sound. One customer did a review for B4. You can watch it in https://youtu.be/OA9bluZ6kMU (We really appreciate the blogger for his efforts)
- For satefy reason, the device can't work while charging. Charging time: 2~2.5h; Working time: 4~4.5 h; The indicator will turn to green when charging process is finished.
- Due to there are microphone effects on all tubes, you may hear some signal interference noise caused by 4G, Wi-Fi. Please keep the distance between your phone and B4.
- B4 is a innovative tube headphone amp. You may meet some problems while using it. Prompt and courteous customer service. For any questions, please contact us at nobsound@doukaudio.com. We will get back to you within 24 hours.
Parameters:
Frequency response range: 0-100K-0.1dB
Gold-plated input / output socket
NE5532 OP chip (can be upgraded to better OP chips like BB or Muse)
Original nichicon electrolytic capacitor
TOP HiFi Original DALE resistors
Precision rings resistance
Battery: Lithium batteries, voltage: 12V, 1000mA
Charging time: 2-2.5 hours to charging full the battery
Working time: 4-4.5 hours
Output power: 450mW
SNR: 99dB
Suggest load impedance: 16-400Î©
Color: Black / Silver
Size(L*W*D): 115 * 69 * 23 mm / 4.53 * 2.72 * 0.91 in (without knob)

Trouble Shooting:
Q: Right channel has static. Tried different source and headphones. No helpã€‚
A: If there is static noise in one channel, normally it is caused by the tube of that channel. Maybe it has a poor contact after the long shipping process. You can open the chasis and adjust the screw near the tube while listening(contact us and we will give you a photo with marks to help you find it). Also, there is a small possibility that the tube is broken. You can buy a 5899 tube in local shops, which is very normal to see. And we will refund you the cost.
Q: It broke just now four loud pops and it's dead. Very disappointed.
A: Mainly because the battery is run out of power. Please charge it. If not help, please contact us.
Q: The Amp has a lot of electronic feedback/interference when a cellphone is hooked up to it or nearby. It creates popping in the headphones.
A: Vacuum tubes are easy to be interfered by devices that can trandfer siganl like cellphones, routers. Please keep the amp away from them.
Q: Won't hold a charge, sounds like something is loose inside.
A: The charger is broken. Please contact us to get a new one.

Packing List:
1 * headphone amplifier
1 * power supply
1 * 3.5mm audio cable
1 * band

Country	USA
Binding	Electronics
Brand	Little Bear
Color	Black
EAN	6245435006898
Label	Douk Audio
Manufacturer	Douk Audio
Model	6245435006898
MPN	6.24544E+12
PartNumber	6.24544E+12
Publisher	Douk Audio
Studio	Douk Audio
ReleaseDate	0000-00-00

Little Bear B4 Portable Vacuum & Valve Tube Headphone Amplifier HiFi for Phone

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