Incorporating four channels of renowned preamplification, independent silk controls, two channels of DI inputs, and an M-S Decoder into a 1U enclosure, the 5024 is a workhorse equipped to enhance the front end performance of any digital or analogue recording system. Each channel of the Portico 5024 is based around the custom transformers and class-A circuitry found in the best-selling 5012.

In addition to 72dB of gain, the 5024's mic pres include individually selectable phase, mute, phantom power, a selectable frequency high pass filter, and the Silk circuit which yields the rich warmth and presence of the renowned classic designs. Channels 1 & 2 of the 5024 feature a high-Z input designed for instrument level sources. Channels 3 & 4 feature an M-S switch, which enables Mid-Side decoding without the use of multiple console channels.

Low Noise, Low Distortion Operation
Much care was given in designing the 5024 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 5024's sweet, whisper-quiet performance.

Portico 5024 Mic Pre Features

Microphone Input
The microphone input is balanced but not floating, 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 designed by Mr. Neve that permits a full +25 dBu input signal to be handled at unity gain without an input pad over the whole audio spectrum. This innovative solution 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.

Line Outputs
The main output signal comes from the output transformer secondary which is balanced and ground free. A ground free connection guarantees freedom from hum and radio frequency interference when connected to a balanced destination such as the input to another Portico module or a high quality ADC. Maximum output level is + 26 dBu, which provides a large margin over and above the likely maximum requirement of any destination equipment to which the 5024 is connected.

Mic Gain
A 12-way precision rotary switch covering from Line (0) and Mic from 0 to 66 dB in 6 dB steps.

Trim
A continuously variable pot provides +/- 6dB level adjustment on each channel

In and Thru 1/4" Jacks
These 2 jacks on both CH1 & CH2 are used for DIRECT INJECTION (DI) or INSTRUMENT inputs, and are simply paralleled and wired together. Inserting a plug into either jack breaks the normal MIC input and the user has the full range of MIC GAIN and TRIM. These jacks have a 3 mega ohm input impedance that will provide less loading (better highs) than most DI boxes. The sheer amount of clean gain that is available makes these inputs extremely versatile.

Silk
This feature 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. 

M/S
The M/S button engages Mid-Side decoding on channels 3 & 4. Channel 3 level controls the mid signal, and channel 4 level controls the side signal.

Instrument Inputs
Balanced or unbalanced Hi-Z input for instruments using the Mic Pre's gain circuitry.

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

Mute
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 below 30 or 90 Hz can be attenuated at 12dB / Octave, leaving the range above this unaffected. This gets rid of building rumble, air handling motor hum etc.

Phantom Power
Provides 48V phantom power to microphones

Portico 5024 Mic Pre Specifications

Frequency Response:
Main Output, no load,
-3 dB @ 2 Hz
-3 dB @ 160 kHz

Noise:
Measured at Main Output, unweighted, 22Hz-22kHz,
Terminated 150 Ohms.
With gain at unity better than 92 dBu
With gain at 66 dB better than 56 dBu
Equivalent Input Noise better than 123 dBu

Gain:
Unity to +66dB in 6 dB steps,
Trim continuously adjustable from 6dB to +6dB
Line Input:
Trim continuously adjustable from 6dB to +6dB
Maximum Output Level:
Maximum output from 20 Hz to 40 kHz is +25 dBu.

Phantom Power: 48 Volts DC +/- 1%

Total Harmonic Distortion and Noise:
@ 1kHz, +20 dBu output: Better than 0.002%
As above, Silk Engaged: Better than 0.2% Second Harmonic
@ 20Hz, +20 dBu out Better than 0.004%
@ 20Hz, +20 dBu out Better than 0.020%
IM Distortion: Better than 0.002%

Slew rate Better than 4 V/uS
High Pass Filter:
Frequency: Selectable either 30Hz or 90Hz
Slope: 12 dB/Octave Bessel