A Short Overview Of Audio Amps
At the center of those systems is the power amplifier. This essay should also help you figure out which topology is best for your particular application. Tube amps used to be widespread some decades ago. Aside from the original music, there are going to be overtones or higher harmonics present in the amplified signal. A lot of people describe tube amps as having a warm sound versus the cold sound of solid state amplifiers.
One more disadvantage of tube amps, however, is the low power efficiency. Tube amps, however, a quite expensive to produce and thus tube amplifiers have by and large been replaced with amplifiers making use of transistor elements which are less expensive to make.
Usually bipolar transistors or FETs are being used. The working principle of class-A amps is quite similar to that of tube amplifiers. The main difference is that a transistor is being used instead of the tube for amplifying the audio signal. Because of this these amplifiers require big heat sinks in order to radiate the wasted energy and are usually fairly heavy.
Class-AB amplifiers improve on the efficiency of class-A amps. They employ a series of transistors to split up the large-level signals into two separate regions, each of which can be amplified more efficiently. As such, class-AB amplifiers are generally smaller than class-A amps. However, this topology adds some non-linearity or distortion in the region where the signal switches between those areas. Typical switching frequencies are between 300 kHz and 1 MHz. Due to non-linearities of the pulse-width modulator and the switching transistor itself, class-D small audio amps by nature have amongst the largest audio distortion of any audio amplifier.
Class-T amplifiers or “t amps” attain audio distortion which compares with the audio distortion of class-A amps while at the same time offering the power efficiency of class-D amplifiers. Therefore t amplifiers can be made extremely small and yet achieve high audio fidelity.