Rupert Neve Designs Portico 542
Unlike digital emulations, the “True Tape” drive circuit works by feeding a custom-designed transformer acting as a “record head”, which in turn is coupled to a correctly equalized replay amplifier. As the voltage rises on the “record head”, saturation increases, and a soft clip circuit engages at higher levels to round off peak transients. The sound of the tape circuit can be further modified with selectable 15 / 30 IPS modes and a pre/post-tape blend control. In addition to the tape circuit, the 542 also has the variable Silk & Texture circuitry found in the Portico II series of modules, which allows the engineer to fine-tune the harmonic ratio and tonality on the output transformer.
While in the olden days, tape’s non-linearity was generally looked upon as more of a curse than a “feature”, the advent of digital systems that operate in a completely linear fashion has made many appreciate the quirks of non-linear audio processing. Unlike linear designs, non-linear devices require the user to actively experiment with gain staging to find the “sweet spot” of the circuit. Although this requires a small amount of effort on part of the engineer, if used properly, the effect can add a dynamic aspect to performances that can enhance the impact of a song.