Senin, 19 November 2012

Power amplifiers

Amplifier 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 there is usually treble is less smooth, less noise fast, broken voice, buzzing, tested middle ground bass sound is lost. so you do not have to believe what people say 100%. Quality amplifier built-up certainly different from the amplifier assembly, the circuit will be the same but the quality depends on who assemble. Want to know the secret? Here are a few tricks to try. COPING hum: Power amplifiers are often used in the field blazer. The series is said to said the bell was assembled. But you do not immediately attracted to this power, the circuit is rather complicated and difficult to understand intelligence reflects the person who first desain. I think a great power is the power of simple, inexpensive, easily assembled and rational. We do not need to use the component with high prices such as tantalum capacitors, power MOSFET and other expensive. This does not determine the quality of the power amp once we raft. Great power sometimes cause hum, to overcome that is to separate the signal ground (ground socket, chassis ground) and ground power. SETTINGS TO CIRCUIT IDLE trimpot: Turn the trimpot the current (if any) until the drain current of 50-100mA on each power transistor, in order to avoid defects treble volume positioned above at 10. The risk heatsink so hot! (This marks the setting klass A-AB) SETTING OFFSET trimpot DC: At the time no signal input, turn the trimpot offset so that the voltage at the speaker actually read 0 volts. If you do not want to bother, use and trust only circuit with ic HA17741 type of Hitachi or other qualified IC brand! This is the heart of the series, 90-95% of the quality of the circuit is determined from IC!!! OVERCOMING THE VOICE sluggish / LESS fast: Use the pre-amp circuit to increase the signal of at least 2 times. normally and should pre-amp circuit using IC op-amp with +12 V minimum supply-12V. Raise his mid tone! you do not want to just use the tone control circuit IC that is mid-him! The secret is not in his mid-tones alone but the signal output from IC op-amp is usually great. TREBLE SPLITS: Excessive treble will damage the power amp, power instead of going out even exhausted. Sort it out, attach the filter capacitor 1nF to the power amp input to ground to ensure that the signal is not disabled. Always use a quality active components such as ICs and transistors, the price difference will also be 500 different results. Use a large and short as possible, especially for foot power transistors, and the transistors should be directly soldered to the PCB. CAPACITOR SUPPLY ... Usually power for field use supplay transformer 50V CT 50V, 42V or at least 42V ct. The greater the supply voltage is greater wattage channeled though written in a series of just 300-400 Watt. This course uses elko capacitor-voltage 80-100V. 10.000uF/100V capacitor will be equal to 4X10.000uF/50V. Try to use a strong elko temperature 105 'C. Capacitors are strong in supply of more than nominal voltage written on the body, usually exceeded by 25%. For example, the capacitor will equal 4700uF/50V 4700uF/63V 105'C 85'C. So that was not fast elko explode if given full voltage, keep the temperature as cold as possible. BASS LOST IN THE FIELD: Try using a driver speakers that have a large spool diameter fitted with a suitable sized bok. Usually included examples of parameters and reference dimensions bok, but given the reference box is not always as expected, not only on the ACR, Kicker Subwoofer do too. Size is usually larger than bok-bok bok2 sold in the market. If you force use bok from the market, use driver type G12-80 (sorry no fear campaign called brand) speakers with bass tones for a size small bok. Bok wall should be thick, strong and do not forget glued!!! Bok will not be glued to a different sound, especially the bass tones, prove it!!! See also Power OCL modif to speaker 15 "& 18" SENSOR HEAT Form of transistor, the transistor is usually type BD139 MJE340 or it could be lying there in the middle, flanked by a pair of transistors that newfangled same. These transistors should be mounted on the main heatsink to detect the heat generated by the power transistor. It acts to reduce the bias current at the time of the hot heatsink. So what power transistor heatsink and heat must be set in position? Yes objectives nothing to prevent the signal from the defect (in class A or AB), the consequences of heat. This class is not necessary and will not be felt if you just want a bass tones only. Goal setting on. AB grade is still crystal clear sound even though the volume of the maximum rotated position (center field). It does not seem possible, but this is closer. BIG heatsink Not only is it easier electrolytic capacitors explode in high temperatures, power transistors can also break away under stress break the original. For example 2SC5200 transistor has a voltage of 230Vdc break, but if temperature break higher then its rated voltage will drop well below this value, resulting in fast 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. The more heat the temperature will be less ability. The use of cooling is expected that the components remain fresh, fit and durability. COMPONENT SELECTION: TRANSISTOR POWER There are so many makes and models of these transistors, for example MJ15003 & MJ15024-4-5 from Motorola, but unfortunately these components are not manufactured by Motorola again but from ON Semiconductor. Just different brands can reduce the quality and customer trust. Transistor models jengkol usually stronger at high temperatures, probably because it is more airtight. According to some friends, the character of the transistor jengkol the middle is more powerful, especially when it's hot. 2SC5200 from Toshiba, this transistor innards equal to Sanken 2SC2922, and both will break if the temperature is too hot. Sanken 2SC2922 issued tin granules when heated, these weaknesses. 2SC3281, transistor is the most popular, most linear in the cold-warm temperatures and is often used in professional amplifier, but Toshiba is no longer produced, instead ya C5200. If transistor C3281 is still on the market, then it most likely is fake!!! Sanken 2SC2922 most recognized characters padded. Toshiba 2sC5200 low and also most preferred because it is considered the most linear character and suitable to the taste of ear audio DIYer. TRANSFORMER There are two models of transformers are often used, namely EI models (box / conventional) and model Toroid (Ring / donuts). Some say toroid transformer models better because it has a smaller fluk leakage, in fact the same, or maybe bigger toroid radiation. Circuits are sensitive to this flux is high have a gain circuit as a pre-amp and pre-amp head mic. The circuit is usually installed horizontally / flat parallel with conventional transformer email wire arrangement so that the circuit receives a larger drone. Unlike the toroid transformer models are arranged in a vertical wire email so the wires are perpendicular to kits circuit. The effect is the received fluk kit pre-amp head smaller. To overcome this fluk that does not go into the circuit is to download shelding / fortify a solid aluminum plate oxygen impermeable. Plat is of course connected to the ground via a cable. To match the vertical transmission fluk, conventional transformer needs in pairs oblique (side by side be side down) so that the composition of the transformer wire standing, this way is often used in built-up POWER2. It makes us have to choose a high casing. Voltage 50V 50V CT can be obtained by combining the two transformers 25VCT25V, CT is not used, the foot so the foot 50V 25V used only to CT, so the total number is 100V or 50VCT50V. It is worthy to pwr amp power over 400Watt. RESISTOR 5W Resistors on the legs of the power transistor is usually worth 0.5 ohm 5 Watt white boxy. If we dismantle innards it appears there was a circular aluminum wires. It resembles the inductor, the inductor inductive reactance will be high when fed a high-frequency signal that treble tone will be weakened and deformed. But often it is expected to weaken the treble disability. Power required to issue high-pitched (treble) is certainly larger, there is a problem here. Using R 0.5/5W the power amplifier home its only. But often unrecognized 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 that arises is hot and damaged. We recommend using common 2 Watt resistor 00:47 - 1 ohm parallel 2 as starting 4 Watt. Or if you use ohm 2 Watt resistor 0:22 parallel unnecessary because sufficient voltage clamp half (one R 0.5/5W replaced the R 0.22/2W) its ok. FUSE Properties of semiconductor material damage / transistor power amplifier is short, if you use a high enough supply then the destruction of the transistor will invite partners to broken anyway. In order for the destruction of transistor is no need for installation of fuses congregation. 1.5A per power transistor is enough.

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