Rupert Neve Portico 5017 - Mobile DI/Pre/Comp - Manual (Page 6)

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5017 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 5017 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 MIC AND INSTRUMENT / BLEND 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 + 22 dBu, which provides a large
margin over and above the likely maximum requirement of any destination equipment to which the
5017 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.
DI GAIN
Continuous gain control from 0dB to 30dB
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.
THRESHOLD
When signals exceed the “threshold” level, the gain is reduced at a controlled 2:1 ratio, with attack and
release time constants set to standard or fast depending on the internal jumper setting.
SILK
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.
BLEND
Combines the Mic and DI signals on the DI / Blend Output. When Blend is set to fully DI, the 5017
operates with two separate channels.
+48V
Back panel switch makes phantom power available at the microphone input.
PHASE
Push button inverts the polarity of the signal path. The symbol “Ø” is often used to denote opposite
polarity.
HPF IN
The high pass filter is a valuable aid in any signal chain but particularly so in a microphone preamplifier.
Signals below 80hz can be attenuated at a rate of 12db / octave, getting rid of building rumble, air
handling motor hum etc.
INDICATORS
Indicators on the 5017 denote signal presence and clipping on both DI and mic signals, as well as
compressor activation.
INTERNAL JUMPERS
Two internal jumpers in the 5017 can be set to change the compressor from the mic channel to the di /
blend channel, and to change the compressor time constant from fast(default) to slow.
To change the compressor time constant to slow, move the J1 jumper(top of picture) away from the front
faceplate.
To change the compressor position from di / blend to mic, us a pair of tweezers to move the jumper block on J2,
J3 and J4 (behind the mic signal presence LED) to the right (when facing the faceplate).
Threshold HPF Comp /Mic LED
J1: Changes compressor at-
tack/release from fast(closer to
faceplate) to slow
J2/3/4: Changes compressor
circuit from the DI / Blend
path(left side as viewed from
the front) to the Mic path