Rupert Neve Designs Portico 517 500 series mic pre / compressor
Based on the Portico 5017 Mobile Pre, the 517 provides world-class transformer-coupled micpreamp, compressor and DI circuitry with Vari-phase, “Silk” and DI/mic blending capabilities – all in a single 500 series module.
Mic Pre and Instrument Amplifier
The 517’s mic pre – based on the TEC Award-winning Portico 5017 – provides up to 66dB of gain, polarity-reverse and phantom power switches, and the “Silk” circuit for a more vintage vibe. The separate instrument amplifier includes 30dB of gain, a ground lift, variable phase and an instrument Thru connection.
Blended Use
Used as a single channel device for instruments, the 517 can be used to phase align, combine and compress direct and amplified signals. To achieve this, use the DI for the instrument’s direct signal and the mic preamp for the speaker cabinet signal. The blend control is used for mixing direct and amplified signals to achieve the desired tonal blend between the two sources, and the variphase is used to minimize or extenuate phase cancellations between the two signals. To compress the blended signal, the internal compressor jumper must be set to the blend path (this is the default setting). This technique could also be used to create a single, mixed output of a guitar and vocals.
The Compressor
Based around a new LDR (light dependent resister) design, the 517’s opto-coupler compressor has been simplified to a single threshold control with auto make up gain. By default, the compressor is set to a fixed 2:1 ratio with fixed attack and release. To set the compressor, simply dial the threshold control down until the desired amount of compression is achieved. An LED light indicates when the compressor is active.
Vari-Phase
In addition to the standard polarity reverse, the 517’s vari-phase control may be used to adjust phase incrementally. This control is useful any time two signals derived from the same source are combined.
For instance, even with careful placement, the combination of close miced drums and overheads, can often yield hollow-sounding results. By using the variable phase adjust, the direct signal can be phase rotated until the signals are naturally aligned.
This technique is also extremely useful when combined with the internal blend control on instruments. A bassist or guitarist using both direct and mic’d signals can blend the two into a single output, using the variable phase to reach an optimal alignment. By adjusting the phase in the 517, the musician or engineer can find the absolute best mic position without regard to the phase relation to the direct signal.
Specifications
Mic Gain
A 12-way precision rotary switch controls gain from 0 to 66 dB in 6 dB steps.
Trim
Continuously variable +/-6 dB level control.
+48V
Engages phantom power on the microphone input, as supplied by the 500 series rack.
Polarity
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.
Level Meter
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.