“We wanted a general purpose direct box that would not only direct inject electric keyboards but more importantly would get the best out of the electric bass and guitar. The unexpected results were astonishing; the Sigma DI quickly became the favorite of the bass and guitar players.

Always looking for the better mousetrap, as new DIs came to market we put our box to the test. In every head to head comparison with both active and passive store bought DIs the Sigma box came out on top.

You know the sound; you hear it in the recordings of the Jays, Lou Rawls, Teddy Pendergrass, the Stylistics, the Spinners, MFSB, Grover Washington Jr. and Patti LaBelle. It’s ‘The Sound of Philadelphia’.

The day Sigma opened its doors and the 35 years that followed it was the only DI I used for recording musicians like Ronnie Baker, Gerald Veasley, Steve Beskrone, Bob Babbitt, Anthony Jackson and many others.

It was only at the urging of a musician friend, who wanted a Sigma DI of his own that I considered building a few. Unfortunately I found that the heart of the Sigma DI, a high quality audio transformer, had been out of production for years and was just about impossible to find.”