The Purple Peaker Equalizer from Dan Armstrong has a three-position switch to select one, both, or neither of the two peaks. In the "1" position, the Purple Peaker introduces a 12 db peak centered at 4000 Hz which gives the instrument more "presence" or "bite". In the "2" position it produces the same presence peak plus a 7 db peak at 200 Hz to give the instrument more bottom or "punch". In the "Off' position neither peak is produced, but the guitar's signal is still improved, since the Purple Peaker's low impedance 200 ohm Output eliminates signal loss and hum pick-up, even with very long cables. The Purple Peaker EQ makes weak-sounding instruments sound fuller, and full-sounding instruments sound super. The equalizer is also excellent for musicians who want to record themselves by plugging directly into a tape machine without going through an amp. The Purple Peaker has Input Impedance of 100 k Ohms, and an excellent Signal-to-Noise ratio of 90 db.