No discussion on overdrive pedals is complete without looking at the Ibanez Tube Screamer. There have been several minor variations of the pedal released by Ibanez, and a larger number of variations sold by boutique pedal manufacturers. As our guitar heroes die, it seems the equipment they used sometimes takes on a mythical status. In my opinion, this is the case with the genuinely legendary Stevie Ray Vaughan and the Tube Screamer. This results in some silly prices for original pedals, and a lively market to convert different pedals to Stevie’s model.

Nevertheless, the green Ibanez box is a very smooth sounding pedal that retains the guitar timbre well, and for that reason works well with single coil guitars. There is not an enormous amount of drive available, and the tone control is subtle. Like many overdrive pedals, there is some middle boost, caused by the bass cut before overdrive, and treble cut afterwards.

Another common use for these pedals is as a middle booster to drive a valve amplifier harder. This is done by setting little or no drive, but with the level set high.

In the schematic, you can see two silicon diodes, back to back, in the negative feedback path of an op-amp. This arrangement gives symmetrical soft-clipping.

by GM Arts