Controlling Overdrive From Guitar

A few days back i got the trick of controlling the overdrive gain from the guitar itself. Its a good substitute for a overdrive pedal if you want to change tone on fly. It was a new thing for me. I dont like many effects chained into the tone (I like only a mild overdriven amp). I guess its the same technique by which the greats used to control the tone when sound processors were not there.

I gave my amp a very high dose of overdrive, bass and volume and kept the volume down from the guitar, and most amazing tone i get when at low volume, it gives a very bright clean sound with a lot of sustain and feedback. Also i get the harmonics at low volume (no probs for neighbours & parents), the amount of crunch increases as volume is turned up from the guitar.