Little Bear B4 Amplifier BLK HiFi Portable Vacuum Valve Tube Headphone Amplifier

Little Bear B4 Amplifier BLK HiFi Portable Vacuum Valve Tube Headphone Amplifier

Description:

- B4 is a tube headphone amplifier, the sound feels warmer than transistor products. it has built-in battery protection circuit. It powers off after is is fully charged automatically, the charger LED turn to GREEN. Can realize the use of human intelligence. Else. When you charging the battery. This B4 amplifier can’t turn ON until you pull out charger interface.  because we design it work like that, just make battery safe.

Direction for use:
- 1.   .Ipod/Cellphone/MP3 :connect to B4 INPUT socket by 3.5 to 3.5 audio cable.
- 2.   .Switch & volume control share the same knob:Please rotate the VOL Knob to the left,then plug in your Headset/earplugs to HEADPHONE socket.
- 3.   .Turn on your media player, and tune VOL knob from left to right till the volume issuitable.
- 4 .Turn off: When you do not want to listen, please take off the headphone,turn down the volune till the machine is powered off.

Notice: when you using B4 with your cellphone,if you fell some “zhi~zhi “ noise into your headphone. That’s usually the cellphone effect it. Sometimes, it’s cellphone WIFI,or 4G signal effect the tube. Then the noise into the sound. That’s normal. Because all tube with some microphone effect case. Solve way is . just move your cellphone as far as possible from the B4.

Performance parameters:
- Frequency response range：0-100K-0.1dB
- Gold-plated input/output socket
- NE5532 OP chip (you can upgrade it to a other better brand OP chip. 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 ：16-400Ω
- Size：115*69*23 mm1(Length XWidth X Depth)(The measurement doesn't include the knob size.)
- Reference data for 5899:
- (A type Amplified state):
- Heater voltage:6.3V                        Heater current:300mA
- Anode Voltage: 100V                    Cathode resistor: 220 Ω
- power amplification factor:20
- Anode essential resistance:4000Ω
- Transconductance:5000um/s       Anode circuit:8.5mA
- Grid voltage:-9V