Simple Audio Projects - Part 2
Preamplifiers, Tome Controls, and Filters
Approx construction cost US$11 to $15
A compendium of useful audio amplifier circuits for the experimenting constructor
Although the power amplifiers described last month have a respectable amount of gain, some signals may be too weak to produce an adequate loudspeaker output without additional amplification. They can also be further weakened by an excessive mismatch between the signal source and the amplifier. Tone controls are usually required when music is being reproduced, and restricting the bandwidth will clarify speech signals, especially under noisy conditions. These three issues: pre-amplification, impedance matching and tailoring the frequency response, are covered in this article.
More details on this construction project can be found in the June 2002 issue of EPE Online, the world's first web-delivered electronics and computing hobbyist magazine.
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