You've absolutely heard people say that all AC/DC songs sound the same. Engineer Mike Fraser, who has worked on numerous AC/DC records including their newest one Power Up, has a bone to pick with those people. Fraser said in an interview with Brave Words that AC/DC certainly has their own sound, but it's a little more complicated than that.
"I know what everybody means; they think AC/DC is like a three-chord band," he said. "Well, if you listen to their songs, it's not three chords, it's more than that. But that's their sound.
"Some bands have great success in a direction and they get bored with that, so they change it, they try to chase what's popular. AC/DC doesn't because they love doing it, they are not doing it for money, fame, or anything. That's kind of the difference."
Plus, let's all be real with ourselves for a second. There are plenty of AC/DC songs that are really hard to nail down on guitar, if only because of their rhythmic intricacy.