If you are looking at buying a stereo amplifier, but are not sure which is the best option for you, look no further than this installment of the SmartHouse buyers guide. We cover the ins and outs of what you need to know before buying a top notch integrated or pre/power amp as well as links to reviews of our favorite players.
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.
Home Cinema Stereo
Stereo amps can be used in home cinema set-ups as well. You don’t get the surround and centre channels, but well set-up stereo speakers do a remarkably good job of creating atmosphere for movies. Stereo amps tend to be better at reproducing music as they don’t have the (electrical) noise-inducing digital processing of AV amps. AV amps cost three to four times as much as stereo models of a similar quality.
Should I leave my amp on all the time for best results?
All audio electronics perform better when they are warmed up, and this is particularly the case when it comes to -amplifiers. If there’s no way that you can leave it on all the time, make an effort to switch it on at least 20 minutes before listening.
What is bi-wiring and bi-amping?
Bi-wiring is when you run -separate cables to the treble and bass/mid terminals on the speaker. In most instances, this improves sound quality so long as identical cables are used. Bi-amping is using two stereo amps to drive one pair of speakers, using one amp to drive the treble and the other for the bass/mid sections of the speakers.
Why do valve amps have so little power?
Valve amps are inherently low powered in absolute terms – at least when you compare them to their transistor-based cousins. But when partnered with high-sensitivity -loudspeakers, they are quite capable of producing perfectly adequate head-banging levels.
SmartHouse Favourites
We’ve got full reviews of our standout favourite amplifiers online. In no particular order – here they are listed below, click on the model number to go straight to the review.
Creek Evo: Not the most accurate, strictly, but its lively, energetic musical presentation is entirely lovable
Denon PMA-700AE: One of a growing number of new low cost amps, it offers good timing and analysis at up to moderately high volume le
Marantz PM7001 KI: A self-effacing amplifier which serves the music admirably with fine bass, sweet treble and unforced detail
Ayre AX-7e: High end sound at a sensible price. Lacks the balls of less revealing designs but has precision in the timing department that is rare
Densen Beat B150: Gorgeous bass: slight treble dryness detracts only a little. Good sense of scale and rock-steady rhythms appeal too!
Lyngdorf TDA 2200: Sophisticated modular all-digital amp with room EQ, capable of adapting to the listening environment
Naim NAC 122x/NAP 150x: Musically rewading with outstanding sophistication, grip and insight for such a modestly priced design
