Thursday, March 14, 2013

Tips and Tricks on Audio Power Amplifier Circuit

Amplilfier power series from the beginning until

now did not experience any changes. Some say this series is good, but

the series was good fitting assembly and tested the results are not as

we expected.

The problem is usually treble is
less subtle, less sound, sound breaking, buzz, middle of the field
tested the bass sound is lost. so you do not have to believe what people
100%. The quality amplifier built-up would differ greatly with the
amplifier assembly, a series can be the same but the quality will depend
on who manufacture it.

Here are a few tricks to try

How to cope with a buzzing sound

Power

amplifiers are often used in the field blazer. This circuit is said

said person is a bell assembly. But you do not immediately interested in

this power, the circuit rather complicated and difficult to understand

reflect the intelligence of people who first mendisainnya. In my opinion

a great power is the power of simple, inexpensive, easily assembled and

rational. You do not need to use expensive components such as the price

of tantalum capacitors, power mosfet and the other expensive. This does

not determine the quality of the power amp so that we raft. Power of

sometimes causing buzzing, to overcome that is by holding the line input

jack ground to the ground with 10-22 ohm resistors. So do not just take

the ground input from the ground but held first with the R 10 ohms.

How to setting bias trimpot

Rotate

the trimpot bias (if any) until the drain current of 50-100mA on each

power transistor, in order to avoid defects treble in volume in the top

position at 10. The risks are so panassss heatsink! (This setting marks

on plate A-AB)

Offset trimpot setting

At

the time of input without a signal, turn the trimpot so that the

voltage on the speaker offsets actually read 0 volts. If you do not want

to bother, use and entrust it with ic type series from Hitachi HA17741

IC brand quality or other! This is the heart of the series, 90-95% of

quality is determined from the IC circuit this!

Overcoming the voice

Use

pre-amp circuit to increase the signal of at least 2 times. normally

and should pre-amp circuit uses IC op-amps with 12 V minimum

supply-12V. Raise his mid tone!

If hard you do not want to just use the tone control circuit IC is his mid!

The secret is not in his mid tone alone, but the signal output from the IC op-amps are usually large.

Treble rupture

Excessive

treble will damage the power amp, power rather than out even ngedrop.

Handle, attach the filter capacitor on the input 1NF power amp to ground

to ensure the signal is not disabled. Always use a quality active

components such as ICs and transistors, 500 price difference will also

be different results.

Use a large cable and

short as possible, especially for leg power transistor, and this

transistor should be directly soldered to the pcb.

Missing bass in field

Usually

power for field use supplay CT 50V 50V transformer, or at least 42V 42V

ct. The greater the greater the supply voltage watt channeled though

the series is written only 300-400 Watts only. This course uses Elko

capacitors with voltage 80-100V. 10.000uF/100V capacitor will be equal

to 4X10.000uF/50V and of course voltage capacitor is filled with full /

almost full.

Try to use a strong Elko at

temperatures of 105 'C. Capacitors are strong in supply of more than

nominal voltage is written on his body. For example 4700uF/50V 85'C

capacitor will quickly explode in voltage 51V 85'C. And Elko will be

strong 105'C 4700uF/50V voltage supplied more than 50V at a temperature

of 85'C. Elco so that it does not quickly explode if given the full

voltage, keep its temperature as cold as possible, fan with the cool

air.

For speaker

Try

using a driver speakers that have a large spool diameter fitted with a

suitable size bok. Usually included examples of the parameters /

dimensions bok. Size bok bok2 usually larger than that sold in the

market. if you force using bok that from this market, use driver type

G12-80 (sorry no fear brand called promotion) speakers with bass tones

to wall size small. Bok wall should be thick, strong and do not forget

glued! Bok who will not be glued with a different sound, especially bass

tones, prove it!

Heat Sensor

The

form of transistor, the transistor is usually type BD139 MJE340 or it

could be located in the center, flanked by a pair of transistors having a

certain equal. These transistors must be mounted on the main heatsink

to detect the heat generated by power transistors. It acts to lower bias

currents at the hot heatsink. So what heatsink and power transistors

must be set diposisi hot? Yes objectives nothing to prevent the signal

from the defect (in class A or AB), with consequent heat. This class is

not necessary and will not be felt if you only want the bass tones only.

Goal setting on. AB grade is still crystal clear sound even though the

maximum volume positioned rotated (in the middle of the field).

It is unlikely, but it's closer.

Large heatsink

Not

only electrolytic capacitors are more explosive at high temperatures,

power transistors can also break away under stress break the original.

For example 2SC5200 transistors have the break voltage of 230Vdc, but if

temperaturya high voltage values ​​will break his fall well below this

value, resulting in faster transistor is damaged. Use of heatsink and

cooling fan is very important not only to reduce the heat, more than it

can prevent the transistor from break / damaged and weakened output.

Increasingly hot temperatures will be more or less ability. Use of this

cooling is expected for the components remain fresh, fit and durability.

Choice Component

Power Transistor

There

are so many types and models of these transistors, for example MJ15003

MJ15024-4 and-5 from Motorola, but unfortunately these components are

not manufactured by Motorola again but from ON semiconductor. Transistor

model jengkol usually stronger in the high temperature, probably due to

more airtight. 2SC5200 from Toshiba, this transistor is equal

dalamannya Sanken 2SC2922 Korea, and both will break if the temperature

is too hot. 2SC2922 Sanken issued tin granules when heated, this

weakness, the Japanese technology is better than Korean technology.

2SC3281, this transistor is the most popular and frequently used in

professional amplifier, but Toshiba does not produce much, if still

there in the market, then it most likely is fake!

Transfomer

There

are two models of the transformer which is often used, namely EI model

(box / conventional) and the model toroid (ring / donut). Some say the

toroid transformer model is better because it has a smaller flux leak,

in fact the same. Circuits that are sensitive to this flux is high

berpenguatan circuits like pre-amp head and mic pre-amp. The circuit is

usually installed horizontally / flat parallel to the structure of a

conventional transformer wire so that a series of emails received

reverberation is greater. Unlike the model toroid transformer is

arranged in a vertical wire their email so that the wires are

perpendicular to circuit kits The effect is the flux of the pre-amp kit

receive a smaller head. To solve for this flux does not enter the series

is by downloading shelding / fortified with non-magnetic plate such as

aluminum plate and copper plate / sheet pcb board. Plate is of course

connected to ground via a cable. To match the flux in a vertical

transmission, the conventional transformer needs to be installed side

(the side be side down) so that the arrangement of transformer wire

stand upright, this method is often used in built-up POWER2. Voltage 50V

50V CT can be obtained by combining the two transformer 25VCT25V, CT is

not used, the foot 25V 50V so that the legs be made only to CT,

bringing the total number is 100V or 50VCT50V. It deserves used for pwr

amp powerless over 400Watt.

Resistor 5 Watt

Resistor

on the power transistor legs are usually valued at 0.5 ohm 5 Watt white

square. If we dismantle dalamannya it appears there was a circular

aluminum wire. It resembles the inductor, the inductive reactance

inductor will be higher when fed a high-frequency fractions so that

treble tone will be weakened and deformed. Power required to remove the

high notes (treble) of course greater, there is a problem here. The use

of R 0.5/5W on its home-based power amplifier ok-ok only. But often do

not realize the cause of damage to the speakers and power amplifiers is

the high treble tones. Treble is not out but was hit by a pwr amp so

arising is hot and damaged. We recommend using common Watt resistor 2

12:47 - 1 ohm parallel 2 so that counted 4 Watt. Or if you use 0:22 ohm 2

Watt Resitor unnecessary because the voltage clamp diparalel quite half

(one R 0.5/5W replaced one R 0.22/2W) its ok.

Fuse

Nature damage

to semiconductor materials / transistor power amplifier is short, if you

use a supply that is high enough then the destruction of these

transistors will invite their partners to be damaged as well. In order

for the destruction of this transitor congregation not need the

installation of fuses. 1.5A per power transistor is considered

sufficient.