Fancy Amplifier back to projects
Based on the 'gainclone' hype in the DIY audio land a fancy audio amplifier is made. The amplifier employs an LM3886 amplifier chip from National Semiconductor. All external parts are put toghether according to the datasheet from national.
A lot of stories circulate about the great sound this audio amplifier chips produce. Also a lot of modifications such as using special capacitors and resistors or small power supply decoupling capacitors making it sound even better are described and discussed widely on the internet. All nonsense of course, it simply is a very good integrated amplifier design from National. Then why is this amplifier so very popular? I think it is only because it is incredibly simple to build a good amplifier with the chips, and DIY audio freaks are generally not that good in electronics, so this is what they can achieve. And of course, when you built something with love, you are likely to over-rate your product.
Nevertheless this design sounds good, but it looks even better! Completed with anodized aluminium frontplates and input switching relais. It has only a input selector knob and a volume knob. The indicator light changes with the input selection. Total output power is 68Watts in 4 Ohm and 38 in 8 Ohm, although the cooling can be a problem here, since the housing is not that large to lose the heat generated at full power output. Nontheless the amplifier will safely shutdown when a too high temperature is reached.
Two buttons can be seen in the photo, one is for the input selection and the other for the volume level. Which input is selected can be read out by the color of the front LED light. Each channel has its own color, which can be blue (shown) red, green or yellow.