While the majority of the harmonic richness found in Rupert’s designs is a product of the output transformer and surrounding class-A amplifiers, this step-up input transformer also imparts a unique musical enhancement of its own. The technical reasons for this are primarily a result of the reactive impedance characteristic of the input transformer and how that interacts with the connected microphone, resulting in subtle, non-linear harmonic enhancement of the lows and an unmistakable sweetness in the high frequencies.

While creating the input stage for the Shelford Channel and Dual Shelford Pre, the goal was not merely to recreate the classic designs, but to advance them: combining the unmistakable sound of the vintage technology with wide-bandwidth frequency response, consistently excellent amplifier performance at any gain setting, and extremely low noise operation. To achieve this, the custom transformer designs were carefully optimized and complete MuMetal shielding of the input transformer was implemented. The resulting preamplifier is flat from below 10Hz to above 60kHz, resulting in the purest possible tone and the very highest levels of versatility.

What is Silk?

The exclusive Silk & Texture circuit on the Dual Shelford Mic Pre allows you to fine-tune the amount (and type) of harmonic content in the output stage. This means your signal can be adjusted from quite transparent to settings that produce nearly 10x the amount of sonic color as Rupert’s vintage modules – and in two very unique modes. No matter what sound you’re looking for, Silk can get you there.

When you apply SILK RED, you’re enhancing harmonic content generated by the highs and high mids of your source. This adds a sparkly sheen to the top end, and is often ideal for sources including vocals, snare, strings, pianos, and other acoustic instruments. With SILK BLUE, you’re enhancing harmonics generated by the lows and low mids of your source. This tends to “beef up” a signal from the bottom up, making it a great choice for drums, bass guitars, heavy electric guitars, male vocals, and synthesizers.

The Dual Output Level Transformers

Complementing the Silk circuit are the custom-designed output transformers, which use Rupert Neve Designs’ distinctive dual output topology. These offer both Main (+26 dBu) and -6dB (+20 dBu) outputs, allowing the engineer to drive the preamps fully into classic transformer saturation without clipping converters and other devices later in the chain.

The main outputs are designed to capture a more pristine sound at high levels, avoiding any nonlinear coloration of the output stage. The -6dB outputs allow an engineer to fully drive the Shelford – adding dynamic tone with these same nonlinear “colorations” – without clipping most professional interfaces. On drums, vocals, guitars and other instruments, these outputs let you easily hit the transformer’s “sweet spot” of nonlinear harmonic content, bringing a recorded performance to life in a way that other preamps simply cannot match.