This equalizer combines on one chassis, the Pultec world famous EQP-1A3, MEQ-5, as well as a high low pass filter, all with Pultec’s legendary passive design introduced in 1951. The passive design utilizes capacitors and chokes to produce the equalization curves. This is by far the most costly method of building an equalizer, but the dramatically smooth sound of these circuits “speak” for themselves. Pultec’s have been copied as plug-ins and imitators have attempted hardware copies, but ultimately, the only equalizer that sounds like a Pultec is a Pultec! Trutone owns the only 4 units produced just before Pultec closed in the early 80’s.