Amplifier Bridge-Tied Load (BTL) and how 100 W plus 100 W equals 400 W
Bridging stereo amplifiers and having them quadruple their power was a cloudy topic for me for a long time. Then I finally understood how it's possible for a, say, 100 Watt amplifier to use two channel and produce four times the power instead of two. I will now explain it briefly and simply, so that anyone can understand what's going on. This article assumes that the reader is familiar with bridge-tied load ( BTL) configured amplifier, even if not fully understanding the mechanics. This concept is tied to some basics in electricity. Most of us are familiar with Ohms law, even though we would not have used it before. The law states that a device (i.e. speaker) that loads a power source (i.e. amplifier), draws power only as much as the loading resistance or impedance allows. The the amplifier produces voltage and the higher the resistance of the speaker is, the less current is allowed to flow and less power is used. Resistance strangles the current flow in a sense. So when
