ART Pro Audio Dual MP - Two Channel Tube Preamplifier - Manual (Page 4)

* ** *N No otte e:: Be sure to turn down or mute the output of the Dual
MP when engaging or disengaging Phantom power.
Additionally, when disengaging, allow 30 - 45 seconds for the
power to completely dissipate. Most microphones will make a
sound like air leaking from a tire when phantom power is dis-
connected, but some can make some very nasty low rumbles
and whines as well.
* ** *A An no otth he err N No otte e:: Dynamic microphones should not be affected
or damaged if they are plugged into a line where Phantom
power is present. However, if the mic doesn’t need it, don’t use
it. Some things are best left untested!
P Ph ha asse e S Sw wiittc ch h
The Phase switch is provided to reverse the phase of a signal.
This switch works on Pins 2 and 3 of the XLR Output jack of the
channel. In the Normal position, the signal is in-phase. In the
Reverse (or “in”) position, Pins 2 and 3 are reversed as the sig-
nal is changed to 180 degrees out of phase.
In multiple microphone applications, the placement of the
microphones can affect the phase of a signal. If two micro-
phones pick up the same signal from different locations, the
result can be a hollow or frequency “shifted” sound. In some
cases it may sound as if an instrument disappears if it happens
to be 180 degrees out of phase. Depressing the Phase switch of
o
on ne e channel can remedy this problem. Likewise, if a micro-
phone cable is wired incorrectly, when used with a properly
wired cable the signal will be out of phase.
* ** *N No otte e:: for single microphone applications switching the phase
switch in and out will produce little to no change in the output
signal.
Special Effects
For industrial, metal, or just “flavor” textures experiment with
the Dual MP. Cascading the channels can produce overdrive
and tube distortion that can add interesting textures when
blended with vocals and different instruments. Placing signals
purposely out of phase can yield interesting results. No harm
will come to the Dual MP with this type of experimentation
however, be sure to have output and monitoring levels turned
IIn np pu utt C Co on nttrro oll
The input control sets the amount of input gain of the Dual MP.
Turn the control clockwise to increase gain and counterclock-
wise to decrease gain. You may control two ranges of gain with
this control, +26 to +60dB and +6 to +40dB. Selection of the
gain range is made with the +20dB gain switch.
S So on niic c C Ch ha arra ac ctte err L LE ED D A Arrrra ay y
Four LEDs are provided on each channel which display how the
tube gain is affecting the input signal. These LEDs are calibrated
with the tube circuitry to give you an accurate visual of its out-
put signal (**Note: these LEDs are pre - output level control).
The first LED is labeled Cln (clean). The tube is producing a
clean output when this LED is lit.
The next two LEDs are labeled “warm”. This is the normal oper-
ating range for the Dual MP. At this level, the tube is producing
an output signal which most would call “warm” or (those ever
over-used) “tube/ retro/ vintage/ rich/ etc/ etc”. Whatever you
would like to call it is fine. You’ll find the output signal has an
enhanced bottom to low mid quality with smooth high frequen-
cy detail.
The last LED is labeled “Clp” (Clip). This LED will light at
approximately 6dB before audible distortion occurs. If this light
flickers, do not panic. The unique design of the Dual MP causes
the tube to distort well before any other gain stage. When a
tube goes into distortion it is a gradual process and tends to
sound pleasing for a range before it turns into a distortion box.
After some use you’ll find the “sweet spot” of the Dual MP is
with this light flashing fairly regularly.
+ +2 20 0d dB B G Ga aiin n// N No orrm m S Sw wiittc ch h
Use the +20dB Gain/ Norm switch to set the gain range of the
Input control. When the switch is in the out (Normal) position
the gain range is +6 to +40dB. Depressing the switch adds
20dB of gain. With the switch in, the gain range is +26 to
+60dB. With most microphone applications you’ll find using
the Dual MP with the +20dB gain switch in is needed in most
situations. Use the setting that best fits your application.
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