There's no doubt about it, the Ibanez TS9 Tube Screamer is one of the, if not the most popular guitar overdrive out there. Guitar players such as Stevie Ray Vaughan used it as the TS9 really let's the sound and feel of the guitarist come through. It is one of the most copied pedals and was used as a basic circuit for many later pedals.
Plugging it in makes you feel as if you went back in time. It sounds like old favourite records. This mid boost is really prominent and perfect for rock and blues as it cuts through the mix, yet keeping your initial guitar tone right there.
The Tube Screamer went through many variations. It started in the late 70's as the TS-808 Overdrive Pro, then in early 80's the first TS9 was produced and some more variations came after. Nevertheless, the Ibanez TS9 Tube Screamer remains the original - a must have!