Amplifiers come in two basic forms: integrated and preamplifier (pre) plus power amp combinations. Integrated simply means that both pre and power -sections are in one box. There are definite advantages to separating the low level, delicate signals in the preamp from the radiations of a power amp, so the more ambitious designs come in two or more cases. In some cases, each channel has its own power amp called a monoblock.
Amplifiers use two basic technologies: transistors or valves. Transistors are popular because of their practical and technical advantages, but valves – aka tubes – live on owing to aspects of sound quality that trannies can't replicate. If you want to play your music loud, use trannies; if you -appreciate acoustic music, try valves.
The fundamental of amp/speaker -interfacing is power rating and speaker -sensitivity. You can drive a high-sensitivity speaker with a ten watt valve amp, but it takes a 200W behemoth to get the best out of speakers which present a difficult load. As a rule, you can't have too much power.
How to choose an amp
The main areas in which amps vary are: timing, dynamics, stereo imaging and transparency. Timing is the ability to -present the attack and decay of each note precisely; amps with strong timing have a snap and coherence that is very appealing.
Dynamics is a general term for the ability to portray variations in level between -individual notes and is different to dynamic range (the difference between the loudest and softest notes). Dynamically strong amps tend to have more life and energy.
Stereo imaging is how solid or three-dimensional an instrument or voice sounds. The point of having two rather than one speaker is to make it possible to recreate the soundstage of the original recording, thus amps that have strong imaging skills can create a sonic space that seems to extend the room.
Transparency of detail is the most -obvious difference between amps. One amp will present more subtlety than another, but the drawback with using this as your main criterion is that a forward or ‘bright' sounding amplifier will emphasise detail at the expense of overall musical coherence.
