How easy is it to drive an op-amp from a 9v battery?

MikeHunt79 said:
I've seen some portable headphone amps that do it, they mention something about "floating ground". Do they simply use a voltage divider, or is it a little more complex than that?
Of cource you can use a passive voltage divider but it consumes power which could sometime be critical. It's better to use an active voltage divider, an opamp or a special IC.

http://focus.ti.com/lit/ds/symlink/tle2426.pdf
 
I prefer the two 9V myself as split supplies.

Yes you can run one battery and use a resistor voltage divider with a filter cap, and it works just fine, but if you can use two batteries, that's less parts you have to use and you get a better voltage swing with 2.

I use the +/-9V battery supply when testing freshly built amp circuit, so I can get the amp working on lower voltage, before I give it the "real" power from the mains transformer. If you accidently short the 9V batteries, no smoke most of the time.