Amplilfier power circuit from the beginning until now not much changed. Some say this is good circuit, the circuit is good but fitting assembled and tested the result was not as we expected. The problem that there is usually treble is less smooth, less noise kenceng, broken voice, hum,
tested middle ground bass sound is lost. so you do not have to believe what people say 100%. Quality amplifier built-up must be different from the amplifier assembly, the circuit can be the same but the quality will depend on who assemble. Want to know the secret?
Here are a few tricks that need to be tried.
COPING hum :
Power amplifiers are often used in the field jacket. The circuit is said to Bell said people were assembled. But you do not immediately attracted to this power, the circuit is rather complicated & difficult to understand reflect the intelligence of the person 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 components with high prices such as tantalum capacitors, power mosfet and the other expensive. This does not determine the quality of the power amp once we raft. Power of sometimes causing buzzing, to overcome that is by holding the line on the ground socket input ground with 10-22 ohm resistor. So the ground is not directly take input from the ground but held first with the R 10 ohms.
SETTING HOW BIAS trimpot :
Turn the bias trimpot (if any) until the drain current of 50-100mA on each power transistor, in order to avoid defects in the position treble volume over 10 hours. The risks are so hot heatsink! (This setting marks on plate A-AB)
SETTING OFFSET trimpot :
At the time of the input with no signal, turn the trimpot so that the voltage offset at the speaker actually read 0 volts. If you do not want to bother, use and rely only circuit with ic type of Hitachi HA17741 or other quality brand IC! This is the heart of the circuit, 90-95% of the quality of the circuit is determined from the IC!
OVERCOMING THE VOICE lackluster / LESS :
Use a pre-amp circuit to raise a minimum of 2 times the signal. normally and should be pre-amp circuit using IC op-amps with minimal supply +12 V-12V. Raise his mid tone! you do not want to just use the tone control circuit IC that there is a mid-her! The secret is not in the tone of his mid-course but the output signal of the IC op-amps are usually large.
TREBLE SPLITS:
Excessive treble will damage the power amp, power instead of out even. Handle, attach the filter capacitor at the input power amp 1NF 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 and short as possible, especially for leg power transistors and these transistors should be directly soldered to the pcb.
BASS LOST IN THE FIELD :
Typically power for field use supply 50V CT 50V transformer, or at least 42V 42V ct. The greater the supply voltage is greater wattage channeled though the series was just written 300-400 Watt only. This course uses Elko capacitor with a voltage 80-100V. 10.000 uF/100V capacitor will be equal to 4X10.000uF/50V and of course the voltage of the capacitor is filled with full / almost full.
Try to use a strong Elko at temperature 105 'C. These robust capacitors in the supply of more than nominal voltage written on the body. For example 4700uF/50V 85'C capacitor will quickly explode in voltage 51V 85'C. And Elko 4700uF/50V 105'C going strong more than 50V voltage supplied at a temperature of 85'C. Elko is not so quickly explode if given the full voltage, keep the temperature as cold as possible, dikipas with the cool air.
FOR SPEAKER
Try using a driver speakers that have a large diameter spool fitted with a suitable size bok. Usually included examples of the parameters / dimensions bok. Bok size is usually larger than bok2 sold in the market. if you force using the bok of this market, use driver type G12-80 (sorry no fear campaign called brand) speakers with bass tones to the size of a small bok. 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 transistors, these transistors can usually type MJE340 or BD139 also located there in the middle, flanked by a pair of transistors that newfangled same. These transistors must be mounted on the main heatsink to detect the heat generated by the power transistor. It acts to lower the bias current at the time of the hot heatsink. So what power transistor heatsink and heat must be set in position? Yes the goal nothing to prevent the signal from the defect (in class A or AB), with the consequence of heat. This class does not need and will not be felt if you just want a bass tone alone. Goal setting on. AB grade is the sound remains clear despite maximal volume rotated in position (center field).
It is unlikely, but it's closer.
LARGE heatsink VOLT
Electrolytic capacitors are not only more explosive at high temperatures, power transistors can also break far below the original break voltage. For example 2SC5200 transistor has a voltage of 230Vdc break, but if temperaturya break higher then the value of its voltage will drop well below this value, resulting in faster transistors damaged. The 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 it will be increasingly less ability. The use of cooling components is expected to remain fresh, fit and durability.
COMPONENT SELECTION :
TRANSISTOR POWER
There are so many types and models of these transistors, for example MJ15003 & MJ15024-4-5 from Motorola, but unfortunately this component is no longer manufactured by Motorola but from ON Semiconductor. Transistor model jengkol usually stronger at high temperatures, perhaps because it is more airtight. 2SC5200 from Toshiba, this transistor dalamannya Sanken 2SC2922 as large as the Koreans, and they will break if the temperature is too hot. Sanken 2SC2922 issued tin granules when heated, this weakness. 2SC3281, this transistor is the most popular, most linear and often used in professional amplifier, but Toshiba does not produce much, if still on the market, then it most likely is a fake!
TRANSFORMERS
There are two models of the transformer is often used, namely EI model (box / conventional) and the model toroid (ring / donuts). Some say toroid transformer model is better because it has a smaller kobocoran fluk, in fact just the same, or perhaps a larger toroid radiation. Circuits are sensitive to this flux is a series of high berpenguatan as head pre-amp and mic pre-amp. The circuit is usually installed horizontally / flat parallel to the arrangement of a conventional transformer wire email so that the circuit receives a bigger buzz. Unlike the model toroid transformer is arranged in a vertical wire email so that the wires are perpendicular to the circuit kits. The effect is that the received kit fluk pre-amp head is smaller. To overcome this fluk not to go into the circuit is by downloading shelding / fortified with solid aluminum plate made of oxygen impermeable. Plate is of course connected to ground via the cable. To match fluk vertical transmission, a conventional transformer need to be in pairs side (the side used as the bottom side) so that the composition of the transformer wire stand upright, this method often used in built-up power2. Voltage 50V 50V CT can be obtained by combining two transformers 25VCT25V, CT is not used, the leg so the foot 25V 50V only be used as a CT, so the total number is 100V or 50VCT50V. It's worthy to pwr on 400Watt power amp.
RESISTOR 5W
Resistor at the legs of the power transistor is usually worth 0.5 ohm 5 Watt white box-shaped. If we dismantle in it appears there was a circular aluminum wire. It resembles the inductor, the inductive reactance inductor will be high if fed a high-frequency sinya so that treble tone will be weakened and deformed. Power required for high tones (treble) certainly larger, the problem is here. Use of the power amplifier R 0.5/5W home its 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 pwr amp so that arises is hot and damaged. We recommend using 2 Watt resistor regular 0:47 - 1 parallel 2 ohm so counted 4 Watt. Or if using ohm 2 Watt resitor 0:22 diparalel unnecessary because the voltage is pretty half-flops (one R 0.5/5W replaced one R 0.22/2W) its ok.
FUSE
Breakdown properties of semiconductor materials / transistor power amplifier is short, if you use a supply that is high enough then the destruction of one of these transistors will invite their partners to be damaged as well. In order for the destruction of transitor is no need for mounting fuse congregation. 1.5A per power transistor is considered sufficient.
No comments:
Post a Comment