Author: Li day
A chassis with a chassis made of 3mm thick aluminum-made, each side of the chassis uniformly hit 54 φ5mm apertures Serve. Volume 220mm × 170 mm × 80 mm. Front end cap and the inner frame chassis, available thin aluminum material to reduce weight and cost. Charging socket, audio input socket and two transistors on the rear end cover, power switch, indicator, potentiometer, and headphone sockets are installed for easy operation. Second, the circuit board production 3ram board made of an epoxy resin sheet and the thick hollow copper rivets. The size of the chassis to decide the volume of the resin sheet, first setting position just seat 4. Out with a suitable pipe bore hole opener. Then the epoxy board φ3mm drill small holes 20 drilled. Serve riveting rivets. This board strength, not one hundred bad weld, the parts easy disassembly.
Third, the amplifier production amplifier principle pictured above. FIG depicts only one channel of the line, the other channels are identical. Power sharing two channels. The input stage 6N3 served with a double triode amplifier stage by a 6P14. It is a specially designed audio pentode. NATURAL excellent quality, using cathode output connection, in order to reduce the output impedance, the impedance can drive a headphone. Superior to the output of the transformer connection, high-frequency widening, to further improve the fidelity.
On the prepared circuit board, try to use the own lead wires of the part. Flexible use of their own experience. Biliary manufacturers try to use the same tube used for matching the same period. Conditions If you import with the same kind of bile duct. Effect is more ideal. 2W red gun with the best resistance. Wherein R2 is the gate resistance, the recommended quality 0.5W resistor, the resistor noise is also large, then the volume has increased.
C1 is the coupling capacitance, plays the same role as a bridge before and after class, the quality must be good. C2 and C3 with high-quality domestic small-scale electrolysis. The capacity is too large and too small to affect the sound. Do not think that bigger is better.
The scope of the screen voltage is wide, in general. Just install the correct adjustment can not work. But the level of pressure screen will also change the tone, according to their preferences, appropriate changes in the resistance R4 and R5, as long as the pressure does not exceed the limit screen on the line.
Fourth, the production of a power supply circuit
Each gallbladder filament is supplied from 12V DC in the machine, and it is important to use each of the same biliary filaments to be used in series.
Supplying the boosted power conversion by the machine screen to extreme pressure. Therefore, the power to make good or bad will affect the success of the whole production. The power supply is shown below.
BG1 and BG2 composition oscillation circuit, R1, and R2 is a DC bias resistance of the transistor. Oscillating voltage transformer lift boosted to about 220V. And then filtered by the rectifier for each screen electrode used. BC1 and BG2 are a large amplification factor, low current penetration 3DD15 transistor. R1 and R2 are greater than the resistance required of 3W. Resistance of about 600Ω ~ 1kΩ.
Indicator with 12V / 75mA bulbs, light emitting diodes can not be used. Since the lamp brightness level may prompt the internal battery voltage, charging facilitate timely. Capacitors and electrolysis products in general can be. Replacement choke coil primary winding of a transformer with output 6P1. Step-up transformer T can be finished ring or EI type transformers, power greater than 10W, the primary 220V, secondary 12V + 12V, dipping drying process before installation. BG1 and BG2 installed in the chassis rear end cap, the end cap insulating mica sheet, may be coated with grease on the stem contact surface to reduce thermal resistance and enhance heat dissipation effect.
Disconnect the connection with the amplifier when adjusting, and use 220V / 20W incandescent bulbs to leave the load. Changing the value of R1 and R2, so that the brightest light bulb. And several power-off, when amplifiers are connected to the normal.
The rechargeable battery is a dry two 6V batteries in series emergency light, inexpensive this battery, no memory. You can recharge it with. 12V charger available products, made very simple, the charging current is preferably not more than 1A.
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