[puck]

i have been looking around for circuit diagrams for a buffered power supply using an op-amp as a buffer but haven't had any luck. i can get plenty of threads about them but no diagrams. can anyone hook me up with one or are they a total waist of time?

 

[zzz]

Kevin Gilmore has a schematic for such thing on Headwize (http://headwize.com/projects/showpro...lmore3_prj.htm).

 

[puck]

thanks. i was thinking of something for to use with an apheared47 though.

 

[zzz]

Portable? That would draw too much current and batteries are already quiet enough not to need that sort of uber-regulation. If not, then what's the problem with this one? Voltage? Make 22.8K resistor in the top opamp's feedback 14K (I suppose you need +-12V. for some other voltage that would be 10KOhm * (V2 / 5V - 1), where V2 is what you're trying to get). The bottom one can stay as is (it is configured to simply invert the voltage being fed from the bottom).

I'm sure you can find other designs too, this is just what came to my mind first when you asked...

 

[rickcr42]

Did you try a search over at headwize ?
Maybe under "rail splitter" or "virtual ground" ?

 

[aos]

Kevin's PS is about as simple (relatively speaking of course) as you're going to get if you're looking for an opamp driving a rail. In fact I made one on breadboard yesterday to cut down 15V to 10V. You don't have to use OPA548 if you need less current, I used LM6171 and it was happily providing 10V @ 70mA without even getting hot.

While batteries might not be very noisy they might not have low enough internal impedance and their voltage will fluctuate with the load current. So a good PS could sound better than batteries.