Typical parameters of the amplifier

In this article, I want to show you some of the parameters characteristic of the system amplifiers. This is the knowledge that you need to know because On the market today there are many different amplifier manufacturers in the world. But the structure and principles of operation of the amplifier, almost all manufacturers have to follow a standard mechanism. Amplifier can operate in different modes such as Class A, AB, B, D, … depending on the circuit design.

– Power
Amplifier power emitted per unit of RMS. This should be distinguished with greater peak power PMPO lot with operating power of the amplifier (some manufacturers advertise PMPO huge capacity of up to thousands of W, but the actual capacity is very low effective).
RMS Root Mean Square stands, ie ‘the average person’ (you do remember this is another cost to the average of the light). This is a number calculated average power levels generated continuously for a period of time. Reviewed strong or weak power amplifier is not measured at a given moment in time and averaged from many different patterns in a time series. Seized power again while watching this is important, but PMPO (Peak Music Power Output, maximum capacity) just for fun and not know what to eat the whole thing strong weak amplifier.

– Gain
Ratio in logarithm between power input and power output of the amplifier unit is dB. Represents the gain of the amplifier gain capability.

– Frequency Response
Approximately input signal frequency that stable operation amplifier linearity. Usually good amplifier frequency response from 20Hz to 20kHz in audio ear about who can smell. Frequency response as “flat” will demonstrate the capability of sound reproduction possible.

– Efficiency
The ability to make sound power according to the input power of the amplifier. When the electric power supply for the amplifier, only a fraction is amplified audio power output. The amplifier design principles classA underperforms from 10% to 25% (that means if you provide power to 100W 25W power amplifier only sound is emitted), class AB performance with 35 to 50%, the class D with 85-90% efficiency.

– THD
Comparing total harmonic frequencies between the input signal and output sound after passing through the amplifier. The high harmonic distortion and reduces the fidelity of sound so the lower the amplifier THD more realistic sound reproduction, usually less than 0.5% THD right.

– Output Impedance
The amplifier output impedance of the speaker. When paired with the impedance of the amplifier to the speaker, the speaker impedance usually halve the power amplifier should double if the coupling impedance difference.

Distinguishing OTL and OPT
OTL stands for the phrase in English: Output Transformer Less (translation: do not use sound output transformer). OTL first circuit was patented by engineer Julius Futterman as Americans invented in 1954. Then, this circuit has many variations and that once quite prevalent in manufacturing equipment used lights electronic. Until the advent of semiconductor, OTL almost disappeared, no one used, so use it “cost” too much shade and low performance.

Electronic vacuum bulb is the internal components have become high, operate in conditions of high voltage and low current. Because of those attributes of electronic lights, to increase the flow and coordination impedance devices with low impedance and high current as speaker, one must use low voltage transformer at the output, called na the audio output transformer. Audio output transformers (OPT) is the preferred audio believers because it generates even harmonic chord sounds that are quite sensitive to the human ear, amplifies the clatter, tinkling and the details of size of the tracks. But the advantage for this person is a drawback for others. Those who follow the school of engineering importance because it does not like OPT born sound distortion, limiting bandwidth and dynamic range of the sound. They give OTL is an option rather than the use of OPT. Do not have to go through an enormous components, bulky coils with a lot of laps in the output, OTL circuitry can overcome some disadvantages of using OPT circuits, such as speed, strength, dynamic range of sound. In particular, ultra-wide bandwidth of OTL, can be up to hundreds KHz and not impaired in about ten KHz frequency as for OPT. Therefore, in recent years, designed OTL again reappeared in many hi-end products and get people to play sound enthusiastic.

So you already know quite a bit about Home Cinema already! Will stay behind on the common semiconductor amplifiers as Amp ClassA, ClassB, ClassAB, ClassD …

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