How much power should the audio amplifier choose?

                             How much power should the audio amplifier choose?

In an audio system, it is really not as simple as you imagine to use the power amplifier well, it is really necessary to discuss it.

1. What power amplifier should I use?

Generally, before choosing a power amplifier, the first problem you encounter is how much output power to choose. This is not only related to the effect and stability that a sound system can achieve, but also related to the cost of the system. We all know that there are many ways to express the output power of a power amplifier, including rated output power, music power, and peak power. That is, the smaller the load impedance, the greater the output power of the power amplifier. Theoretically, the impedance is reduced by half and the output power is doubled. Now let's define the rated output power of the power amplifier. The so-called rated output power means that under a certain load impedance (usually 82) and a certain harmonic distortion (according to 0.1% or 0.3% given by the manufacturer), a sine wave signal is fed into the input terminal, and the output power is On the end load, the maximum power obtained can be obtained by using the formula P=U2/R. Here I want to remind everyone that although it is very strict to define the rated output power of the power amplifier, some manufacturers are still not so strict in their publicity. Some use the rated power at small loads as the nominal value, and some even mark it with music power or peak power. It is suspected of misleading the public. This depends on our use of the knowledge and experience we have to judge.

Secondly, how to choose a power amplifier in a hall? In practical applications, we generally do not directly choose a power amplifier with 400W output or 800W output. Because of the size of the output of the power amplifier, whether the sound in the hall is loud enough for us is really not the same thing. The output power of the power amplifier of the system, in terms of type, some are for full-range main channel speakers, some are for pushing and pulling panorama speakers, some are for stage return speakers, and some are for subwoofer speakers. It is very large, and at the same time it is related to the sensitivity of the speakers being pushed. In addition, it has a lot to do with the acoustic environment of the hall. The influence of so many factors on the sound pressure level (usually the sound is not loud), we can use a formula to quantify and characterize: W=10 (LP-LS+20Igr) /10LP: test point (radiation distance of the speaker) requirements The sound pressure level dB;

LS: speaker sensitivity dB, given by speaker parameters;

r: the distance m from the speaker to the test point, also known as the speaker radiation distance W: the driving power required by a single speaker, we can use this as a basis to reasonably determine the electric power output by the power amplifier. It should be noted here that the formula - - generally determines the output power of the channel power amplifier. The stage return speaker can be determined according to 30%-50% of the power of the main channel, the output power of the subwoofer amplifier can be determined according to 100%-150% of the power of the main channel, and the power amplifier of the auxiliary speaker can be determined according to 50% of the power of the main channel. %-100% sure. Never use gross estimates and determine by imagination. If it is determined in this way, the consequences will either be wasted (the power is selected too large), or the effect will not be achieved, and it is very easy to cause damage to the power amplifier (the power is selected small), unless you are very experienced.

How to make good use of the power amplifier in the audio system

How to judge the quality of a power amplifier For a power amplifier, many people often cannot judge its quality. Just relying on the indicators provided by the manufacturer is often similar to others, and people are confused. Depending on the price, in some cases, high prices do not necessarily mean good products. Today, the author will talk about how to judge the quality of the power amplifier from the actual use situation, of course, it is another matter to use the instrument to test the indicators.

get an amp,

We can simply judge from the following aspects:

1. Appearance and packaging - The outer packaging of a power amplifier first depends on whether the packaging box is upright, whether the printing is exquisite, and whether the information is complete (specifications, origin, certification, etc.), and then whether the shockproof filling material of the packaging is environmentally friendly. Those that are well packaged, reasonable, and environmentally friendly can be considered good power amplifiers.

2. The appearance of the power amplifier is to check whether the surface treatment of the panel is fine, whether the shell plate is thick, whether the screws and screw holes are accurate, whether the knobs, connectors, and word printing are accurate and clear. If they are all good, it can also be considered that the quality of the power amplifier is good.

3. Turn on the power amplifier to check whether the volume and weight of the toroidal transformer match the marked output power, whether the appearance is rough, and then check whether the filter capacitor is a genuine product, whether the capacity and withstand voltage are sufficient (generally, the capacity is 10000uf and the withstand voltage is 100- -200v) Whether the wiring is clear and reasonable, especially the high-power tubes: - look at the number, as the output power increases, the number of high-power tubes can be configured from 8 to 24 or even more.

4. Judging the protection circuit It is relatively simple to see whether the protection circuit module is relatively simple. The regular protection circuit has functions such as over-current, over-voltage, over-temperature, and time delay. Poor power amplifiers only have a power-on delay, no other protection measures, and the circuit is very simple.

5. The noise of the power-on fan is low, there is no transformer vibration sound, and no other abnormal sound, otherwise the power amplifier is a defective product.