Hi Elinor, if you mean the knob on top that is connected to the "fishing line", no that will adjust the cartridges azimuth. Depending on what vintage WTT you have if there is another knob of top over the vertical shaft, yes that will raise and lower the arm for VTA after you loosen the knob of the side of the vertical shaft. Older models, like mine, you just loosen the knob on the side and move the arm manually up or down to achieve the correct VTA.
WellTempered TT - VTA Adjustment
Can someone tell me if the VTA is increased - increasing cartridge/arm angle making a brighter sound - by turning the adjustment clockwise or counter-clockwise?