Amplification
Integrated or separates, useful power, matching the speakers
An amplifier has one job: reproduce its input voltage while delivering the current the speaker demands, without distorting on peaks. The most common mistakes are not about brands but about sizing and gain matching — both checkable on paper.
Integrated, pre + power, or active
A good integrated removes an interconnect, a pair of connectors and a power supply: at equal budget it often beats entry-level separates. Separates win when the power amp's supply becomes genuinely generous or when cable length calls for a balanced link.
Active speakers move the problem: no amp/speaker matching to worry about, but a level-critical preamp and often a long run to the speakers.
Do not stack volume stages in series (streamer + preamp + amp with its own pot): each cascaded attenuation costs signal-to-noise ratio.
How much power do you really need?
Doubling power buys 3 dB. Going from 50 to 200 W gains only 6 dB of maximum level: the audible difference usually comes from current reserve, not the headline figure.
Quick calculation: target peak level, minus speaker sensitivity, plus distance loss (about 6 dB per doubling) gives the decibels needed, hence the watts. Allow 6 to 10 dB of dynamic headroom for musical peaks.
A small amp clipping damages tweeters more than a large amp used sensibly: unused headroom beats an amp permanently at its limit.
Gain and level matching
If you always listen between 8 and 9 o'clock on the dial, overall gain is excessive: noise floor rises and usable control range vanishes. A 4 V source into a high-gain preamp creates exactly that.
Fixes: adjustable source output, in-line attenuators (-10 or -20 dB), or a lower-gain preamp. It is transparency for free, or nearly.
Check impedance matching: source output impedance at least ten times lower than amplifier input impedance, otherwise bass and dynamics sag.
Classes, heat and use
Class A: remarkable linearity and midrange, poor efficiency, lots of heat — plan ventilation. Class AB: the dominant compromise. Modern class D: excellent control and efficiency, sensitive to cable capacitance. Tubes: higher output impedance, best with stable, reasonably sensitive loads.
Leave 10 to 15 cm above and beside the chassis, and never place an amp in a closed cabinet without airflow.
A 20 to 30 minute warm-up is audible on most amps: judge them warm.
Common mistakes
- Choosing watts from the spec sheet without checking 4 ohm behaviour.
- Stacking two or three volume controls in series.
- Low-current amp on a speaker with a low impedance minimum.
- Enclosing a class A or AB amp without ventilation.
Checklist
- Power calculated from sensitivity, distance and target level.
- 4 ohm behaviour verified.
- Overall gain matched: real usable volume range.
- Source/input impedance ratio at least 10.
- Adequate ventilation, judged warm.