I am working on a project for my electronics III class and I am at the point where I need a power supply and I want to build it myself, however I am not sure how to design and connect it. The device I am making consists of a mono pre-amp (K1803), a 7w Amp (K4001), and a Sound-To-Light Unit (KM103). I have built a box and mounted all three units inside with a 1/4" mono connection in to the pre-amp and the output of the amplifier connected to a 3.5" speaker. I can run the power supply at 17vdc, and the components need 10mA, .5A, and 10mA respectively. Can anyone help me with the power supply design? Any help would be greatly appreciated.

 

For those meager requirements, I'd just use an old 12-16V wall wart transformer with a full wave bridge rectifier and a big filter cap. If you want or need to regulate the voltage, I'd add an LM317, which you can adjust to whatever you want. But you'll need more voltage from the transformer to allow for dropout in the regulator (and of course the bridge) A fuse never hurts.

 

This circuit was supplied with the manual for the K4001 amp. Would it work to power all three devices? 7w amplifier power supply

 

Sure, no problem, as long as the "7W" is not a continuous rating, which it cannot be if it's only drawing 10mA. Depending on what you're doing, you might choose a beefier transformer, maybe 1A instead of the 0.5A. Looks like you don't need a regulator? The amp needs to reject power supply ripple.

 

This from our Completed Projects Forum

Power Supplies

Project | Author | Submitted Double adjustable power supplies | cumesoftware |04/27/2007
Regulated wall adapters | cumesoftware |07/23/2007
Digitally selectable voltage voltage regulator using LM317 | dileepchacko |05/21/2008
ATX & Rack Mount PSU | doug3460 |07/12/2009
Power Supply / Prototyper all scrap/spare parts used. | Jassper |09/13/2009
Battery-operated 1 amp current source | someonesdad |05/26/2011
Simple LM317 Power Supply | T.Jackson |12/08/2011

Something I wrote long ago:

Basic Bench Top Power Supplies

 

Thank you Weyneh, your information has been very useful and I plan to go ahead and see what happens, hopefully good things.

Thank you Bill for the article/blog, it was really helpful. I wasn't sure what a wall wart was but you made it really clear. I learned a lot just reading through that thread.