When to choose a pure post stage power amplifier

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insiders have been very clear that the lower part of the combined power amplifier below 10000 yuan is not worth considering. Especially when the new combined power amplifier is released, the latter level shrank seriously, and the reported power is extended to all the combined power amplifiers.

actually, many years ago, there was no such thing as cutting power and reducing power. Now that the arena has shrunk, riddled with fraud. Years ago, a small flagship power amplifier of ten thousand yuan, changed into pure post grade, 60W x 3+22W x 4, with HTPC+D2, the 7 big boxes are pushed to have taste! In the absence of subwoofer situation, feel strong sofa * *, today, in so many audio forum, talk about the most is the “push”, many manufacturers are 100-200W * 7 of the nominal power, but also push said, let me have been depressed, no understand. I no longer to analyze the manufacturers why to do this, the post level of power amplifier is to use a large number of copper and aluminum! As long as a little older people should know, copper and aluminum used to be only a little more expensive than iron, and they were not worth much.

many friends don’t know much about the performance of the amplifier. It’s wrong to think that as long as the power is large enough, it’s a kingly way. What’s the difference between the post and pure post amplifier of the combined amplifier? Those friends open their mouth to “control”, “parsing”, and so on, and do not know how the power amplifier can achieve these performance.

A friend of

once consulted me for a 2 channel pure post stage. I put forward two extremely critical but not familiar concepts of “damping coefficient” and “conversion rate”.

The most basic index of

power amplifier: power rating.

today’s American and European power amplifier will be labeled with the rated power. The old power amplifier is also the method of marking the power with the rated power. Generally, the power in the case of low distortion (such as the power measured under 0.015%, 20-20kHz, and more advanced power amplifier is measured in 0.008%). If you want to have a powerful output power, a powerful power supply is absolutely necessary. The size of the power reflects the intensity of the sound, that is, the sense of quantity.

The second basic indexes of

power amplifier: all kinds of distortion.

has shown that this is directly related to the size of the power. When the power of the amplifier is large enough, and only a small part of the power is used, the distortion will be much smaller.

combined power level is often use a pair of power tube, power tube pairing has great influence on the distortion of power amplifier is used, advanced directly to the production line to the paired devices (such as the old power amplifier distortion is very small, million yuan in the year to the equivalent of $one hundred thousand today.). The cost is very high, now the number of million yuan within the power amplifier is not do the same. Today, the power pipe matching is not good, it is more important to use its small power to reduce the distortion in high power. The distortion reflects the quality of the sound, that is, the texture.

The important index of

advanced power amplifier: damping coefficient.

an advanced power amplifier, in addition to the power and distortion, its output back resistance has a great relationship with the control of the bass quality. To ensure that there is very little output impedance in large current environment, we must first have high quality large power transformer, large current rectifier circuit and powerful capacitor filter circuit. These advanced combined power amplifiers are not available because of space and cost constraints. And the pure post grade power amplifier is several times more than the combined power amplifier in this respect. Secondly, in order to achieve strong transistor output impedance of the output power and the minimum, pure power amplifier is adopted after the parallel tube power to control the number of combined type power amplifier is better than several times, and combined with a power amplifier on the power output tube (see that small radiator can be installed on the number of on the power tube)?.

, of course, the thickness of the horn line, the copper content and the quality of the connection column have a direct influence on the damping coefficient. The damping coefficient reflects the control quality of the power amplifier to the bass, that is, the control force.

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