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power supply for amp? Answered

Hello!! i built a LM386 amp recently, and i am attempting to build a power supply for it...which is a challenge. so do i have to use a regulator or what? im new to voltage from the wall, i usually build them with batteries, so im new to it. do you think you could post a setup for amps like that that? thank you for your time)) 


Since a 386 will accept 4-12V quite happily, a 9V DC wallwart and a fat 1000uF smoothing capacitor are all you need. You don't need a regulator.


Get a wallwart around 9v(make sure it says DC). Then get a 7805 voltage regulator. My 386 amp uses 5-8 mA, and if yours is close to that then you probably wont need a heatsink.


A wall wart would be a good solution. Chances are you have several unused ones laying around or can get them for free. Choose one with a DC output, with a voltage and current rating sufficient for your circuit. Those ratings are generally right on the label on the plug.

If your circuit needs regulation, then you will want to follow the wall wart output with a regulator. Unless the label on the wal wart says it is regulated, I would assume it is not.

Using one of the LM78XX type of three terminal regulators is an easy way to get a regulated voltage output. These just have a power input, ground, and regulated output pin in a TO-220 package. These are available in fixed output voltages of 5v, 6v, 8v, and 12 v.

There should be tons of circuit schematics for these on the web and this site. Make sure that the wall wart output voltage is a couple volts higher than the regulator output, as many linear regulators require some overhead voltage to work properly. I would definitely get the manufacturers datasheet for the part, as these also often have basic applications circuits in them. The datasheets should be free from the manufactures web site. If you search for the parts on Digikey.com, they also have handy links to the manufacturers data sheets.

Good Luck!