Little Bear B5 MIni Portable Dual Vacuum Tube Headphone Amplifier Audio HiFi Amp

Little Bear B5 MIni Portable Dual Vacuum Tube Headphone Amplifier Audio HiFi Amp

Direction for use:
B5 is a tube mini headphone amplifier,size:115*60*13 mm,like a 6s cellphone. 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. we do not suggestion charging the battery and turn ON the amplifier at same time. it's bad for battery and the sound may with loud noise.

Because 6418 tube with some microphone effect. so. when you hit or knock the B5 metal shell. it's will with some "wing~~~~~~" noise. and that noise will gone about after 5 seconds. that's normal.

Performance parameters:
- Frequency response range:0-100K-0.1dB    
- Gold-plated input/output socket    
- PT2308 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: 5~8 hours    
- Output power:80mW    
- SNR:99dB    
- Suggest load impedance:16-100Ω    
- Size:115*60*13 mm(Length XWidth X Depth)    

Reference data for 6418:
- Heater voltage:1.25V Heater current:10mA    
- Anode Voltage: 60 Cathode resistor: 220 Ω    
- Power amplification factor:20    
- Anode essential resistance:4000Ohm    
- Transconductance:5000um/s Anode circuit:8.5mA    
- Grid voltage:-9V

Package included:
- 1x B5 main amplifier    
- 1x 3.5 to 3.5 cable. for connect your cellphone to B5 amplifier    
- 2x Bandages    
- 1x Charger