I'm not an EE, but I play one in my home lab. I don't understand why this circuit needs an artificial ground at all, since the power source is two 9-volt batte

I'm not an EE, but I play one in my home lab. I don't understand why this circuit needs an artificial ground at all, since the power source is two 9-volt batteries in series. AFAIK that could make a dead-simple bipolar power source +/- 9 volts and get rid of about half the parts. The 10:1 voltage divider is also an interesting concept. It seems to me that what this thing does is attenuate the input signal and then provide a low impedance output to drive the 'phones. I wonder if the writer ever considered something as simple as shunt resistors. Perhaps a "real EE" can enlighten me. FWIW, I use a AudioEngine D1 USB DAC to drive headphones from a computer. It was not cheap, but neither is my time. For portable use I am rocking (with RockBox) a old iPod "video" with aftermarket SD card mod.