Rupert Neve Designs Portico 511 500-Series Mic Preamp with Texture Control

With a big, bold preamp and the flexibility of variable Silk/Texture, Rupert Neve designed the 511 to combine classic sonics with 500-series value. Incorporating the 517's powerful preamp, the 5012's universally useful sweepable high pass filter, and the transformer-saturating power of a variable silk circuit derived from Neve's flagship Portico II Channel, the 511 is a Rupert Neve-designed mic pre for the masses. While it's challenging to design 500-series modules that are equal to their non-500 series counterparts, the team at Rupert Neve experimented with a number of different transformer and circuit designs so they could achieve the same presence and sweetness that is found in the standard Portico Series modules making them perfectly suited for the highest caliber studio environments.

Input Section
Input signals may be derived from Mic or Line sources (make sure 48V is off for line sources!). The input has a 10K ohm non-reactive input resistance that handles a full 22dBu signal without the need for a pad. The pre-amp is a TLA non-reactive design that precludes the loading of microphones with limited driving capability. A primary gain control provides 66dB of gain in 6dB increments for easy recall, with a +/- 6dB trim for fine adjustment. For condenser microphones and powered DIs, there is +48V phantom power. A transient-optimized HPF continuously covering the range from 20-250Hz is included to tame rumble and proximity effect.

Texture
One of the key developments in the 511 is the Red Silk / Texture control from the Portico II Channel. Building on the "Silk" mode found in the Portico Series mic pre-amplifiers, Texture is designed to adjust the actual amount of harmonic music content from the source material, in effect, providing wide range of tonal options for the preamplifier. Like the original Portico Silk, the Silk Red / Texture works by reducing negative feedback on the output transformer and adjusting the frequency response to more closely resemble Mr. Rupert Neve's vintage designs. With the 511, the Texture control allows these techniques to be pushed further than previous designs, adding about 10 times the desirable THD of the original silk control at its maximum setting.

Low Noise, Low Distortion Operation
Much care was given in designing the 511 to produce as little noise and non-harmonic distortion as possible. Carefully implemented signal paths and Class A operation are a large part of the 511′s sweet, whisper quiet performance. For more information, go to Mr. Rupert Neve's Design Notes.

Why Transformers?
The fine subtleties of circuit design relating to sonic performance are gradually becoming more clearly understood. For example, research has shown conclusively that frequencies above 20kHz affect the way in which humans perceive sound quality. But, long before scientific evidence emerged a substantial body of musicians and engineers knew that equipment with apparently the same technical measurements could sound very different. Input and output circuits must be freed from ground dependence so that only the "wanted" signal enters and leaves the processing path. Transformers are the ideal solution. The sweet and silky sound of Rupert Neve's classic old favorite consoles was achieved with big transistors and large high-quality transformers. Rupert Neve Designs Portico modules achieve similar quality today without the bulk or the cost.