The PEX 500 is a one channel transformer coupled Passive Pultec Equalizer. It’s an all discrete design based upon the great 990 amplifier.
The Equalizer is our take on the magical classic Pultec design. It’s got 15db boost of the creamiest high end you’ve ever heard and the most punchy low end heard in the 21th Century. The PEX-500 fits in all 500 series compatible power supplies.