As the second component of the audio chain, the amplifi er’s function is to exaggerate the weak signals from the player, making them strong enough to drive the loudspeakers. You cannot drive the loudspeaker without the amplifier. There are a few players in the market which come with a built in amplifier, but don’t expect wonders from them. You can go for any branded stereo integrated amplifier or a pre/power amplifier combination. The pre/power amplifier set up has certain electrical benefits or advantages compared to stereo integrated ones. Dedicated discrete pre/power amplifi er sets are able to provide the desired current that loudspeakers demand.
When buying an amplifier, look for the following features:
1. Input: The amplifier should have multiple analogue RCA inputs to connect to an external CD player, tuner, phono stage, tape, and auxiliary in.
2. Output: Pre out and/or record out would be an advantage. This can be used to connect an external active subwoofer, a recorder or graphic equaliser.
3. Tone Control: Basic tone controls are a must (i.e.: bass, mid, treble controls) as they are useful to manipulate the sound where needed.
4. Clip/ Thermal Protector: Basically, they are a part of the protection circuitry which helps protect
the amplifier from excess thermal heating and protect loudspeakers from amplifier’s signal clipping at loud levels of listening.
5. Speaker (A, B, A+B): This feature is nice to have for multi-room applications, where you can use two pairs of loudspeakers for separate rooms through the same amplifier i.e.: you can either use a single pair of loudspeakers for your living room or another pair for your bedroom. You can operate both pairs at the same time or separately, by switching between speaker A or speaker B or speaker A+B.
6. Watts: How much power do I need? We are not here to explain everything and add to the confusion. But the truth remains that loudness depends on the sensitivity of the loudspeaker, not the amplifier. So, buy any good entry level or a premium level branded 20–40- watts RMS per channel or more. For the same, use amplifi ers whose power rating is greater than/near about or equal to the continuous or maximum power handling capacity of the loudspeaker.
7. Nominal Impedance: This is a knotty issue. Nominal impedance is the minimum or lowest load impedance (impedance of loudspeaker) that an amplifier can handle. It is a clear indication that a
particular amplifier is well designed or capable to handle minimum possible load impedance eg: if your amplifier’s impedance is 4 ohms, it means it can handle a load impedance (loudspeaker) of 4 ohms or above easily, but may be struggling to operate below or lower than 4 ohms. So do not connect those loudspeakers whose impedance value is smaller than the amplifier’s impedance handling abilities. In general, the loudspeaker’s impedance should be equal or somewhat higher than the amplifier’s lowest impedance handling abilities. There are some amplifier manufacturers who have designed sturdy high current amplifiers which can easily support minimum to maximum loudspeaker load such as 2 ohms, 4 ohms, 6 ohms, and 8 ohms as well.