View Full Version : Which audio amplifier?

07-23-2004, 12:52 PM
Hi all,

For comming week I have plans to convert my MGB to negative ground and install some modern sound (although I'll try to make it "invisible" of course). Can anyone recommend a low ampere amplifier? At this moment I am still working with a generator which will probably have to be replaced with an alternator anyway but I like to keep power consumption low.

Any suggestions?

07-23-2004, 02:09 PM
I'm not up on what's current (bad pun intended) in mobile amplifiers but I do have a couple of general suggestions on the subject.

One thing that mobile audio enthusiasts rarely comprehend is that speakers usually make a bigger difference in how loud a system sounds than the amps do. Obsessing over Watts is exactly the same thing as obsessing over horsepower. Everybody thinks more is better. That's partially true but only if all else is equal, which is never the case.

In a vehicle more power means more weight and more fuel consumption. In an amplifier more power means more electricity consumption. Since a Dummer H2 has 345hp would you expect it to be faster than a 170hp Suzuki Hayabusa? If you thought like most of those car audio guys you would. Speed actually comes from the ratio of engine power to vehicle weight. Audio sound pressure levels come from the ratio of amplifier power to speaker sensitivity. More sensitive speakers need less power to be loud enough so you'll have less load on your electrical system.

It is not uncommon to compare different models of speakers and find that one is ten times more sensitive than the other. One interesting quirk of electronic design is that buying an amplifier with twice the power means you'll probably pay about twice as much whereas buying a speaker with twice the sensitivity may not cost any more, the designer was just twice as smart.

The other way to save power in an amplifier is to choose one that is more efficient. Amplifier efficiency is the electrical equivalent of fuel economy. Traditional amplifiers often deliver only half the power they consume to your speakers. The rest is wasted as heat. The most efficient type of amplifier available is what's called a class-D switching amplifier. Class-D amps can deliver as much as 90% of the power they consume to your speakers. Look for a class-D amp to minimize the draw on you car's electrical system.