Rupert Neve Portico 5024 - Quad Mic Amp - Manual (Page 8)

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sound may well have a flawed data bank! Quality recording equipment should be capable of retaining
“natural” sound and this is indeed the traditional measuring stick. And “creative” musical equipment
should provide the tools to manipulate the sound to enhance the emotional appeal of the music without
destroying it. Memory and knowledge of real acoustic and musical events may be the biggest tool and
advantage any recording engineer may possess.
One needs to be very careful when one hears traces of distortion prior to recording because some flavors
of distortion that might seem acceptable (or even stylish) initially, may later prove to cause irreparable
damage to parts of the sound (for example, “warm lows” but “harsh sibilance”) or in louder or quieter
sections of the recording. Experience shows that mic preamps and basic console routing paths should
offer supreme fidelity otherwise the engineer has little control or choice of recorded “color” and little
recourse to undo after the fact. Devices or circuits that can easily be bypassed are usually better choices
when “color” is a consideration and this particularly is an area where one might consider comparing
several such devices. Beware that usually deviations from linearity carry at least as much long-term
penalty as initial appeal, and that one should always be listening critically when recording and generally
“playing it safe” when introducing effects that cannot be removed.
1. Tsutomu Oohashi, Emi Nishina, Norie Kawai, Yoshitaka Fuwamoto, and Hishi Imai. National
Institute of Multimedia Education, Tokyo. “High Frequency Sound Above the Audible Range,Affects Brain Electric Activity and
Sound Perception” Paper read at 91st. Convention of the A.E.S.October 1991. Section 7. (1), Conclusion.
2. Miland Kunchur,Depart of Physics and Astronomy, University of South Carolina. “Temporal resolution of hearing probed
by bandwidth restriction”, M. N. Kunchur, Acta Acustica united with Acustica 94, 594–603 (2008) (http://www.physics.
sc.edu/kunchur/Acoustics-papers.htm)
3. Miland Kunchur,Depart of Physics and Astronomy, University of South Carolina.Probing the temporal resolution and
bandwidth of human hearing , M. N. Kunchur, Proc. of Meetings on Acoustics (POMA) 2, 050006 (2008)
5024 FEATURES
MICROPHONE INPUT
The microphone input is balanced but not floating, being a variant of an instrumentation amplifier.
Our well-proven “Transformer-Like-Amplifier” (T.L.A.) configuration is used, which includes an
accurate toroidal Common Mode Low Pass Filter that rejects Common Mode signals and excludes
frequencies above 150 kHz. (There are high powered broadcast transmitters at and above this
frequency in several Continents and, even if you can’t hear them, any vestigial intermodulation
products must be excluded!)
When the Mic Gain switch is set to Unity (0 dB), the Portico 5024 microphone pre-amplifier can handle
a balanced input signal of more than +20 dBu without an input attenuator pad! This is a unique feature
that enables this input to double as an additional line input.
THE 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.
However the transformer may be used with one leg grounded without any change in performance. It
is not necessary to “ground” one leg at the Portico output. It would normally get a ground connection
when fed to equipment that is not balanced. 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