Quote:

if I understand your equations correctly, at 18 volts, a 1/8 watt resistor can handle 7 milliamps? |

ok, but - you are leaving out the

*resistance* for us.

10 ohm @ 18V?

18/10=1.8*18=1800mA*18V=32,400 mW = Smoked.

10k @ 18V?

18/10,000=1.8mA*18=32.4 mW = Fine.

And you gotta consider, that's the power of the resistor's rated

*capability*... In your amp no resistor would see 18V unless you're using it to drop power (dissipate for no reason than you need a lower voltage) it'll never see all 18V unless something went terribly wrong in your amp.

Your current-limit resistor on your LED probably sees the most work. Hey, let's find out!

A resistor divider across the rails to make your virtual ground. So if you went 2x4.7k that'll be 9.4k... while this is about the same as the 10k LED resistor, in a voltage divider (series) each resistor drops the V, in this case half of it, so really each resistor is only dissipating 18/9400=1.91mA*18=34.4mW/2=17.2mW.

So yea, the LED resistor is dissipating more. Sneaky, ain't it?