The ins and outs of amplifiers.
Going back to the days of working retail in the early 80’s there was always a known bit about your sound, which remains true today. The weakest part of your system will hold back the sound. Now in general we look at the two ends of the equation, which is the source material and the speakers. Back in the HIFI days of the 80’s we gave a good deal of concern to things like:
Phono Preamps- Which interestingly still a viable concern for those who want to play LP’s or records (vinyl). Phono preamps were built into every receiver or Preamp one might look at. Today Phono preamps are built into very few units. Some stereo only units have this feature and some high-end surround units still do allow phono inputs. If not, good phono preamps are available for starting at about $50.
Preamps- This term is mostly unheard of except for those who have been involved in higher end sound systems. These well-made units can add to the spatial character and openness of a very good sounding system.
Power amps- Definitely these units are not all created equal. AB amplification is the most widely used design and basically speaks to the top of the wave being amplified by the A transistors and the bottom of the wave being amplified by the B transistors. One inherent problem is the switching distortion which occurs at the center point. The standard fix is called negative feedback which is taking the distortion wave and inverting it back into the amp in a cancelling effect, similar to the theory behind active noise suppression in headphone technology. This unfortunately causes the amplifier to be on the harsh side of the sound spectrum. Modern amps employ new designs, which do not have the issues with the feedback circuitry. Therefore, you hear a good clean open amplifier on your speakers and resolve how much nicer music is through a good amp. In commercial systems, we see and hear that amplifiers can improve your system sound or intelligibility greatly.