User Manual

10
sections of the recording. Experience shows that mic preamps and basic console routing paths should
offer supreme delity 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)
MIC PRE CONTROLS
MIC GAIN
A 12-way precision rotary switch covering from Line (0) and Mic from 0 to 66 dB in 6 dB steps.
Selecting the right gain optimizes Noise and Headroom.
TRIM
Provides further gain adjustment, continuously over a range of +/– 6 dB.
LINE
Selects the Line Input XLR. Note that the MIC GAIN control is not active but the TRIM control continues
to function and can be used to adjust the Line Input.
SP LED
This LED is dual function and will be green to indicate “Signal Presence” (a signal about 20 dB below
normal). The LED turns red to indicate near clipping of the MIC / LINE stage (+22 dBu while the pre
actually clips at +25 dBu).
IN and THRU 1/4” PHONE JACKS
These 2 jacks 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, and the sheer amount of gain that is available makes
these inputs extremely versatile (note that if the LINE button is pushed and lit that it overrides the 1/4”
Instrument Jacks, and the back panel Line Input is selected).
+48V
Push button makes phantom power available at the microphone input. Please remember to press the
mute button or turn down monitors and headphone sends or the channel the Portico II is plugged into
before toggling “+48” (and be especially cautious if you use pre-fader aux sends for headphones). Most