The Purple Audio TAV is a 500 Series graphic EQ with ten bands of inductor-based sweetening. This unique module takes a classic console equalizer and turns it on its head, with specialized input and output transformers and gobs of headroom, even at full boost. The TAV's proportional bandwidth means broader curves at lower boost/cut which get narrower as you move the sliders toward either direction's extreme. The TAV is a popular choice in the 500 format for guitars, vocals, and drums, though if you had an entire desk full of them you'd probably use them everywhere.