Specification:
Operating voltage: AC (AC) 12V - 0 -12V
work: single-ended class A
Frequency characteristics: 12HZ ~ 50kHZ (+0 dB,-1dB); 12HZ ~ 120kHZ (+0 dB,-3dB)
Voltage Gain: 21dB
SNR:> 101dB
Slew Rate:> 35V/μS
Quiescent Current: 240mA
Larger board size: 121x108x35 mm
Zoom board can be used as a preamp can also be used as a headphone amplifier The first step; soldering jumper, there have five jumpers, Select the little thick jumper, longer jumper use 0 ohm resistor (already included in the kit)
The second step; welding diode, when welding,pay attention to the polarity of the diode, do not weld backwards (special pay attention to two Zener diode and 1N4148 appearance are very similar).
The third step; weld metal film resistors, metal film resistors also known as resistance, before welding youd better measure with a multimeter.
The fourth step; welding small power transistor (2N2907 and 2N2222), the transistor has two models, make no mistake, do not be mistaken direction.
Step Five: After welding is completed,checke carefully before electricity.Before turning the headset, be sure to adjust the output potential of the left and right channels, as follows, use a voltmeter DC files, red and black pens are connected to the output of + - terminals, adjust 103 (10K trim resistor) let the output terminal of the DC voltage as low as possible , the voltage will be very unstable at this time, to be energized for some time, fine-tune once again,make the voltage closer to 0V as possible.
Package:
1x Class A Headphone Amplifier Board PRE-amp KITS Dual AC12-15V (KITS as photo showing)