The Portico 5012 is a dual channel mic pre featuring Rupert Neve’s custom input and output transformer designs. In addition to individually selectable phase, mute, phantom power and a fully sweepable high pass filter, the 5012 incorporates a “Silk” circuit which yields the rich warmth and presence of his renowned classics.
The microphone input is balanced but not floating, being a variant of an instrumentation amplifer using a “Transformer-Like-Amplifier” (T.L.A.) configuration with a toroidal Common Mode Rejection Low Pass Filter that excludes frequencies above 150 kHz. The T.L.A. is followed by an actual input transformer permitting a full +25 dBu input signal to be handled at unity gain without an input pad over the whole audio spectrum. This combines the advantages of both an “Electronically Balanced” and true transformer input.
When the Phantom voltage is switched off, this input serves as a very high quality line input with an impedance of 10K Ohms.
Low Noise, Low Distortion Operation
Much care was given in designing the 5012 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 5012′s sweet, whisper-quiet performance.
All Portico modules use input and output transformers and almost entirely discrete component amplifiers. In fact, the Line amplifiers on their own, inserted into the signal chain, are capable of enhancing the sonic quality of many signal sources, especially those of digital origin. These are some of the factors that enable the Portico 5012 to work so unobtrusively within the context of a very high quality audio chain.
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.
Incredibly small amounts of musically dissonant odd harmonics can have a disastrous effect on the sound quality. Extraneous noise or interference that finds its way into a signal path seriously impairs performance of the whole chain. Since many control rooms make use of outboard gear that is not well protected from external signals, poor grounding of such equipment can be a serious problem. “Electronically balanced” circuits, much-used in modern equipment, can give very good measurements on the test bench but they do not provide adequate rejection of the stray fields found in every working environment.
Much could be written about this feature, suffice to say, that it gives a subtle option to enhance sound quality in the direction of vintage modules. The Silk button reduces negative feedback and adjusts the frequency spectrum to provide a very sweet and musical performance. We suggest you try it and make your own judgment.
-30 dBu to +22 dBu With reference to the output
Cuts of the output signal post metering and pre Buss Output. Be sure to mute the outputs before engaging phantom power.
High Pass Filter
The High pass filter is a valuable aid in any signal chain but particularly so in a microphone preamplifier. Signals between 20 and 250 Hz can be attenuated, leaving the range above this unaffected. This gets rid of building rumble, air handling motor hum etc.
Provides 48V phantom power to microphones
The To Buss output is unbalanced and has a high impedance output. It is intended for use with the Portico Buss Amp/Monitoring modules. A TRS patch cord is used to connect the 5012 Buss output to one of these bussing modules. The Monitor connection is derived pre mute on the 5012 and will produce a signal at the output of the buss modules that is equal in level to that at the 5012 output. The Monitor output cannot be used for any other purpose.
Flips the phase of an incoming source 180 degrees
RND Portico 5012 Duo Mic Pre
Main Output, no load, –3 dB @ 2.5 Hz
–3 dB @ 125 kHz
Measured at Main Output, unweighted, 22Hz-22kHz, Terminated 40 Ohms, With gain at unity
better than –102 dBu
from 20 Hz to 20 kHz, +25 dBu.
from 20 Hz to 20 kHz is +25 dBu. Total Harmonic Distortion and Noise: from <10 Hz to 80 kHz,
@ 1kHz, +20 dBu output: Better than 0.002% @ 20Hz, +20 dBu out Better than 0.120%
@ 20kHz, +20 dBu out Better than 0.010%
Total Harmonic Distortion and Noise:
from <10 Hz to 80 kHz @ 1kHz, +20 dBu output: Better than 0.020% @ 20Hz, +20 dBu output Better than 0.140% @ 20kHz, +20 dBu output Better than 0.070%
Size 1.75”H (1U), 9.5”W, 8”D