The Ibanez Tube Screamer is a guitar overdrive pedal, made by Ibanez.
The pedal has a characteristic mid-boosted tone popular with blues and rock players.
The TS7 allows switching between a "TS9" mode, in which the circuit and all relevant component values are identical to the vintage model, and a "Hot" mode, which introduces an additional gain stage.
Phish guitarist Trey Anastasio implements two TS9 Tube Screamers in his rig.
A rare and valuable version of the Tube Screamer was the ST9 Super Tube Screamer, which was sold only in Europe and Australia.
The TS9 and TS808 pedals have been reissued, and according to the company, feature the same circuitry, electronics and design components that helped shape the famous Tube Screamer sound.
The classic Tube Screamer sound includes a "mid-hump", which means that the circuit accentuates frequencies between the bass and treble ranges (mid-frequencies).
Some guitarists prefer this sort of equalization, as it helps to keep their sound from getting lost in the overall mix of the band.