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 our flagship Portico II Channel, the 511 is a Rupert Neve-designed micpre for the masses.
Designed for 500 Series by Mr. Rupert Neve
Rupert Neve: “While creating functional 500 series modules is relatively simple, designing those modules to equal their non-500 series counterparts with the current, voltage and space restraints is quite challenging. In creating our own 500-Series Modules, we experimented with a number of different transformer and circuit designs to achieve the same presence and sweetness found in the Portico Series of modules. The result of these efforts is that outside of the slightly lowered headroom, our 500 series modules are nearly indistinguishable from standard Portico Series modules, and are perfectly suited for studios of the highest caliber.”
Input signals may be derived from Mic or Line sources (make sure 48V is off for line sources!). The input has a 10K Ω 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.
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.
With that said, we have taken great care to ensure that the musical integrity of source material itself will not be compromised by these harmonic controls (these are not to be confused with controls from other manufactures that may “incinerate”, “demolish” or “destroy” source material), and we believe they can be confidently utilized to fit the personality of any song, instrument or engineer.
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.
A 12-way precision rotary switch controls gain from 0 to 66 dB in 6 dB steps.
Continuously variable +/-6 dB level control.
Engages phantom power on the microphone input, as supplied by the 500 series rack.
Push button inverts the polarity of the signal path, and illuminates when engaged. The symbol “Ø” is often used to denote opposite polarity.
High Pass Filter
The high pass filter is continuously variable from 20-250Hz and engaged by the HPF switch, which illuminates when engaged. It is a valuable aid in any signal chain, but particularly so in a microphone preamplifier. Signals below the selected frequency are attenuated at a rate of 12db / octave, getting rid of proximity effect, building rumble, air handling, motor hum, etc.
SILK / TEXTURE
Pushing the Silk button engages the red Silk circuit, which reduces the negative feedback on the output transformer, adding harmonic content as the texture is increased. Red Silk accentuates the saturation in the mid and high frequencies, similar to that of the red silk mode on the Portico II Channel. By manipulating the Texture control, the amount of Silk can be changed from essentially absent, to roughly 10 times the amount of coloration / distortion found in Silk from the original Portico Series. With Silk / Texture engaged, the distortion characteristic and harmonic content of the unit are very reminiscent of many of Rupert’s class-A vintage designs.
An Eight-segment LED bar-graph meter displays output level (pre-Silk). The color range proceeds from green for lower level signals, yellow for intermediate signals, and red for high levels. When the 511 is clipped, the highest red LED will hold longer depending on how far above the clip threshold the signal was.
Noise: Measured at Main Output, un-weighted, 22Hz-22kHz, source impedance 150 Ohms balanced. Noise performance can vary depending on the 500 series and / or interference from stray magnetic fields.
Unity Gain: Better than -103dBV
With Gain @ +66dB: Better than -60dBV
Equivalent Input Noise: -125dB
Frequency Response: Main output, no load Main Output +/- 0.1dBu from 10Hz to 31.5kHz -2.6dB @ 120kHz
Maximum Output Level: +23dBu
Total Harmonic Distortion and Noise @ 1kHz: +20dBu output level, no load. Better than 0.0025%
@ 20Hz: +20dBu output level, no load. 0.025% Typical (2nd and 3rd harmonic)
Total Harmonic Distortion and Noise with SILK engaged TEXTURE @ min
@ 100Hz: +20dBu input level, no load 0.015%, mostly 3rd harmonic (typical)
Texture @ 100Hz: +20dBu input level, no load 2%, mostly 2rd harmonic (typical)
Gain Unity: up to +66dB in 6dB steps. Trim continuously adjustable from -6dB to +6dB.
Phantom Power: Supplied by the 500 series rack power supply. Switch selectable on faceplate.
High Pass Filter: Continuously variable swept frequency from 20Hz to 250Hz.
Power Requirements @ +/-16VDC: 100mA