The current market trend shows that the popular audio equipment are transistor amplifiers. They are cheap, each copy has repeatable parameters, they can be very small, and they do not heat. So, it seems like they’re perfect. But there is one more important thing – what about sound quality?
Choosing the amplifier: the order is not random in the case of this article. If you look at the history of audio devices, then you’ll find that the first circuits were based on tubes. As the name suggests, in this case the electron tube is the signal amplifying element. Most tube amps work in class A, which is why their efficiency does not exceed 30%. For class AB constructions it is slightly higher. A large part of the energy in lamp constructions is converted into heat.
Tube amplifiers have a distinctive appearance. Manufacturers are eager to display electron tubes because they give a unique atmosphere. We can therefore recognize tube constructions without any problems. Another characteristic feature are the speaker transformers that can be found in all tube amplifiers. Tube constructions usually do not have any additional functions. We will not find digital inputs or a built-in phono preamplifier there. And let’s keep in mind the delicacy of tube constructions.
In transistor amplifiers, the signal amplifier is the transistor. Their construction is therefore different from tube constructions. The efficiency of transistor amplifiers depends on their operating class. Class A constructions are the most power-consuming. Their efficiency is up to 30%. However, they are rare. Class A transistor amplifiers are mainly audiophile constructions. Their undeniable advantage is, however, high sound quality and low level of distortion, which is why they are eagerly chosen by die-hard enthusiasts of good sound with the right budget. The AB class is definitely the most commonly used in transistor amplifiers.
Their efficiency is higher compared to class A, it is about 50%. They give off some heat, so keep this in mind when setting up your equipment. The sound qualities of AB amplifiers, of course, depend on the particular model, but there is a wide range of constructions that are characterized by uncompromising sound and low distortion.
Class D amplifiers, also known as impulse amplifiers, have been known for years, but only recently have the same reputation as other classes. In earlier years, constructions were created in such a way that the sound quality differed from devices in class A or AB.
The use of the particular technology in the design of the device results in the nature of the sound. And this should not surprise anyone. That’s why various amplifiers are offered. Tube devices, especially the previously mentioned constructions, sound Gentle, warm and smooth. They have a nice, saturated colour. However, they are not as fast as some transistor amplifiers and do not control the speaker units as well. Transistor amplifiers generally cope better with impedance drops of the speakers connected to them, offering more disciplined bass with more energy. Also, the mapping of the details and space can be an advantage of such constructions. Unlike tube devices, most transistor devices tend to present treble in a characteristic way. Sometimes they are dry or grainy, which may give some instruments (e. g. violins, cymbals) a slightly Metallic character to the sound.