Humming sound(not distirtion phat-phat-phat..sound) from Ruby amplifier? How to get rid of it?

I built a Ruby amplifier from here.
When i run it i get a humming sound (phat-phat-phat....type of sound).. whats wrong?

NachoMahma8 years ago
. Hum (particularly at mains frequency of 50/60Hz) is usually caused by bad shields/grounds. . "phat-phat-phat" sounds like it may be a bad capacitor. . Double- and triple-check your construction. It may be a bad connection or a polarized component that is reversed.
frollard8 years ago
Can you record the sound? it's not around 50-60 hertz is it? Does it make the sound with a source connected, with speaker connected? Could be any of your components is blown... :( sorry I can't offer more help.