God bless you can finally ngeposting again. Post this time is how to setting the DCO AREAS and power amplifier BIAS? There are many questions enter via the g + and blog comments asking about this and wants to make a separate post about this, constrained time and bustle. So that delayed a long time ago I do not raise to the surface. Because the uneg-uneg is bad if not expelled, then munculah this post. For audio enthusiasts or novices find out more Yes.
Before stepping on how to setup of a DCO AREAS and power amplifier BIAS, it would be better if you got to the same first two this term. Possible for audio experts already versed in this term, but there is no harm I discuss more about this term. Since both of these terms are closely related to our power amplifier and a very influential and determine whether or not good quality power amplifier outputs we produce. Maybe this time we can only assemble power amplifer can sound, it stops until there. It turns out many of the variables that exist in a power amplifier that we can adjust in order to get the best sound quality. Not all power amplifiers there are settings DCO AREAS and BIASnya. But the truth of all series power amplifier that is definitely no such thing as DCO AREAS and biased. Continue to why kok gak ada power VR and VR BIASnya DCO AREAS? In fact it is there, but it's been on the set of the patent or has a particular value in a fix with maximum results according to the maker. The goal is to make it safe and not in otak-atik again and stayed just install directly the sound, of course this is very favourable for the perakitnya, rather than having to painstakingly for the setting of the DCO AREAS and BIASnya.
Let's discuss a little about DCO AREAS and this BIAS. DCO AREAS or DC Offset DC voltage is coming out on the output speaker power amplifier. The DC voltage is too high the out on the speaker's output can be very dangerous and can cause the spool to our speakers on fire. Therefore the DC voltage on the output speaker should be avoided. Most large wattage power amplifier using dual voltage or symmetrical (positive-negative-ground) and connect the output of the amplifier directly to the speakers without capacitors. At the output or output amplifier can contain a small DC voltage though and not harmful to the speakers. The DC voltage on the output amplifier this is called DC offset.
Then about the BIAS power amplifier. There are several opinions about this. Some say BIAS is the size of the collector current tr final and some say also the BIAS voltage is great between the base and emitter or base and final transistor base mate. And there are also measurement of the voltage on the second basis tr drivers. So there is some sort of measurement for this BIAS. And there are also several measurement techniques in other ways to check the parameters of this BIAS. We will try to lift one by one later Yes.
Once you get to know a little bit about DCO AREAS and power amplifier BIAS, let's try continued on the way its tuning how? The ability of setting on the power amplifier must be mastered if we assemble a big power with the power amplifier. Because if not, then it can cause damage to the tr final and spool the speaker itself. Setting DCO AREAS and power amplifier BIAS is a little tricky. Because the required experience in terms of the parameter values obtained at the time of its tuning. Because each power amplifier has a characteristic and difference of each. This sometimes makes the difference results from a several power amplifier Setup. But this difference is reasonable, as long as we know the parameter's value, then the difference will not be too far away.
In General a power amplifier transistor consists of 3 main parts, namely audio input called "INPUT STAGE ". Then the middle part is called "VASE " and the end of a power amplifier OUTPUT STAGE called " ". The first step to start setting is make sure all paths are correct and the position of the pcb component there is no inverse.
To make it more clear and not wrong settings, please see the following picture below, where the position of VR DC offset and BIAS are. There are 2 VR i.e. P1 is the setting of DC offset and P2 is setting the Bias.
Already seen clearly which position VR DCO AREAS and Biasnya. After you already know the position of the VRnya to the way its tuning. First make sure the condition of the volume enclosed by connecting the input to ground or by covering the potensio volume. The aim is so that there is no voice signal coming into power at the time Setup is in progress. The setting and the setting of the power amplifier input stage part P1 and P2 on the VASE.
Setting the DC offset.
Where P1 vr potensio used to adjust the DC offset at the output path to the speaker in order to get close to 0 volt DC offset or must be under 20 mV. Do I use a multimeter set the scale on a DC voltmeter set 2.5 volt DC range. Then connect the Red probe to the output of the speaker and the black probe to ground or CT. Then set P1 to get VR DC offset most low (close to zero or below 20mV). For images connection please refer to the picture below.
You can see pictures of the first multimeter connection is to check the DC offset. So the results are close to zero or below 20mV. If at the input stage power amplifier you no VR P1, then you live a Bias setting located on the VASE or the middle of the power amplifier.
The BIAS Settings.
Where VR P2 is used to adjust the Bias on a power amplifier. Do I use multimeter 500mA scale sets. Then remove the wires attached and + VCC series. For their connection is the Red probe connect to VCC + elco power supply. And the black probe connect to VCC + pcb power amplifier. Turn on the power amplifier and up to 50mA figures pointing to a multimeter. You can check on line voltage VCC also. With connections to the contrary i.e. a red probe connect to VCC-pcb power amplifier and the black probe connect to VCC-elco power supply. To produce higher quality sound output can be set up to 120mA Bias. But the larger the current Bias will be the better quality audio and risk is the power amplifier will be getting hot. Then you must give the heatsink and the fan or the fan was given as additional cooling, so as not to over heat. Even you can set the current Bias up to 250mA DC offset, origin produced remained close to zero, it will remain safe with the risk of power is hotter. For images connection please refer to the picture below.
Look at the picture on both the bias current checking voltage VCC + VCC and him. You can check one by one. Try the current Bias is nothing more than 250mA. Adjust the magnitude of the bias current capability tr finale. Setting standard bias is 50mA up to 100mA. Depending on the type of powernya. That is clearly the larger currents of bias, then the power will be getting hot.
Well the above seen there are two kinds of checking of the bias on the power amplifier. On the second picture you can see the checking of bias voltage on both legs of the transistor base drivers. And the third image is the checking of the current bias voltage VCC + VCC and him. You can use both ways above to check BIASnya.
Actually there is again another way to check the power amplifier bias, in addition to measure current collector transistor bias in the final cutting line collector TR to the PSU, i.e. way could also measure the voltage across each resistor is mounted chalk walk at the foot of the emitter tr final. Then the measured voltage divided by the value of the resistor. With the formula I = V/r. Prior to step voltage checking R emitter tr final, please see picture below so as not to get confused.
Please refer to the image above. The emitter resistor final (Re) i.e. R1 and R2 are usually worth between 0.22 ohm, ohm 047, there also are using R 0.5 ohm (0.50 ohm). Measure the voltage to find out the current final could be at the foot of R1 and R2. Example let's say the value of R1 is 0.47 ohm, measure the voltage at each distance R1 or R2 by using regular or digital multimeter. multimeter probes connection can go back and forth, it's just when the reverse outcome measured voltage became negative (-). you could reverse the probenya to make it easier to read it. Sets the scale of the multimeter on the 200mV to make it more accurate. In the image above as measured at the point of emphasis is R1 i.e. red and blue. And the results of the measured voltage divided by the value of R (according the above formula I = V/R). Suppose the voltage across R1 (in red and blue dots) measurable 15mV, then I = V/R IE I = 15/0,47 then result about 31.9. Then 31, 9mA it is current TR finale
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