Rupert Neve Designs Portico 5012 Duo Microphone Preamplifier

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 Silk button gives a subtle option to enhance sound quality in the direction of vintage modules by reducing negative feedback and adjusts the frequency spectrum to provide a very sweet and musical performance.

Level Meter -30 dBu to +22 dBu with reference to the output

The High pass filter is a valuable aid in any signal chain but particularly so in a mic preamp. Signals between 20 and 250 Hz can be attenuated, leaving the range above this unaffected.

The 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. Polarity flips the phase of an incoming source 180 degrees.

Microphone Input

The microphone input is balanced but not floating, being a variant of an instrumentation amplifier using a 'Transformer-Like-Amplifier' (T.L.A.) configuration with a toroidal Common… read more 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\0x2032s 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.

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.

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.

To correct these issues, 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 Mr. Neve's classic designs 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.

In order for modules to work together as would be expected (i.e. in a proprietary console configuration) without producing hum, R.F. interference, or other interactions, the connecting interfaces, grounding, levels and impedances must receive careful attention. Each Portico module is a complete integral signal processor that delivers its specified performance independently. This is one reason why RND uses transformers. read less