The drive knob adjusts gain, the tone knob adjusts treble and the level knob adjusts the output volume of the pedal.
The pedal is used to try to mimic the sound of a vintage tube amplifier.
Notable modifiers of the pedal include Robert Keeley of Keeley Electronics and Steve Mc Kinley of Tube Screamer
There has been some misunderstanding about my ts-9 appreciation in the Ibanez page : I love the ts9 , own 8 of them , with one in my everyday pedalboard. Remember what it is said on the I do not think it has been made before on the net but my purpose is to compare serial numbers , which can give age I assume , and op-amp type , which are supposed to give tone (we will discuss about it later).
In doing so, he used an innovative circuit, using the monolithic operational amplifier device, introduced in early 70s, to create a pedal sound different from the "discrete" transistorized 60's fuzzes.
The overdrive is produced using two silicon diodes in anti-parallel arrangement into the negative feedback circuit of a operational amplifier ("op-amp") circuit, to produce soft, symmetrical distortion of the input waveform.
Some musicians have a technician perform modifications to the unit to change the sound to their liking.
Also, Maxon, who produced the original Tube Screamer pedals for the Ibanez brand in the 1970's - 1980's, produce their own version of the Tube Screamer (called Overdrives: the OD-808 and OD-9 as oppose to Tube Screamer, TS).Possible modifications include use of mismatched, or different diodes (for example, a silicon and a germanium device), or more than two diodes in various arrangements, or modified tone circuits.It is also used by the majority of metal guitarists before the lead channel of the high gain amps to make distortion more focused and to cut the low end.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.After the 9 series was discontinued, the "Master" or "L" series was produced.