John Klett had a large stockpile of vintage Marinair and St. Ives input transformers, left over from custom Neve console projects, so he suggested Eisen Audio design a product in which to utilize them. 31267 is a very colorful sounding transformer, with a rich low end, so Jens at Eisen Audio took this opportunity to make solid-state 500 Series EQ module which would emulate some of his favorite vacuum tube program equalizers. This input transformer was paired with a Crimson Audio output transformer, which is “bigger sounding” than most, interfacing with a purpose-designed discrete transistor amplifier and some carefully selected film capacitors. Jens deliberately chose/designed each of these elements to impart an overt and complementary tonal response, trying to achieve a spectral distribution of low-level harmonic distortion which was similar to that of the classic devices which inspired this one. A limited edition of 60 units was sold direct through Eisen Audio during the ’07-’08 holiday (one-time only, discontinued).