1, Powered by USB or Battery, you can utilize the earphone and charging battery at same time. (When you goes outside. Use the power bank to power it. Make it work for longer time).
2, Use lot HiFi components in this version. DALE resistors, Nichicon cap, ALPS Potentiometer, gold interface.and re-design the PCB. Make it work better.and consumption good-looking metal case. You will like it.
3, Use dual-tube in this earphone amp tube mode is: 5899, OP chip is initial TI NE5532, you likewise can upgrade it to other much better OP chip.
4, Match for 32 ~ 600 ohm earphone, work time: about 3 hours. (Charging time: about 2 hours).
Products in choice:
Gold-plated input/ output socket NE5532 op-amp nichicon electrolytic capacitor Precision rings resistance.
Instructions for consumption: 1. CD/MP/MD: link the LINE OUT/ PHONE OUT signals to B3 INPUT socket by RCA to 3.5 audio cable television.
2. Switch & volume control share the same knob: Kindly rotate the VOL Knob to the left, then plug in your Headset/ earplugs to HEADPHONE socket.
3. Turn on your media gamer, and tune VOL knob from delegated ideal till the volume is ideal.
4. Shut off: When you do not want to listen, please remove the earphone, decline the volume till the device is powered off.
Frequency response variety: 0-100K-0.1 dB.
Output power: 500mW SNR: 99dB.
Suggest load impedance: 32-600Î©.
Size: 115 * 69 * 23 mm1 (Length XWidth X Depth).
Reference information for 5899: (A type Amplified state).
Heating system voltage: 6.3 V.
Heating system current: 300mA.
Anode Voltage: 100V.
Cathode resistor: 220 Î©.
power amplification factor: 20.
Anode essential resistance: 4000Î©.
Transconductance: 5000um/ s Anode circuit: 8.5 mA.
Grid voltage: -9 V.
Little Bear B3 Portable Tube valve cellphone headphone amplifier amp.
Newest vesrion, first sale at: 08/20/2015 B3 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, Can realize the use of human intelligence.
Internal adopts miniature American tube5899 Suitable for LOW ESR earphones (performs well with 600Î© DT990 in test.)
Package included: 1x headphone amplifier. 1x USB cable (charge cable 1x 3.5 to 3.5 audio cable (for connect your cellphone to B3 amp)
Features: Portable tube headphone amplifier, the demision is only 11.8cm X7cm X2.3cm (Length XWidth X Depth) (The measurement does not include the knob size.), Including the battery which contains large capacity polymer it is only 190g in weight! Super low voltage work: safe & reliable, do not worry that you might get an electric shock Lithium batteries: enough power supply. 3 hours cruising, the Actual situation with machine: clear voice, High resolving power, details performance skillfully, high frequency sounds mellow, neither too high or too boring.medium frequency sounds pure.Low frequency sounds good-nature, resistance to listen to but not turbid. The whole voice sounds pure, Ryan and Sharpay.Symphony performances well, the sound of each instruments can be reconised clearly.