The Isolated Output; Phase Switch - The GigRig Pro 14 Manual

The GigRig ltd Jan 2009
©
10. The Isolated Output (Out 2)
Isolated output... Output 2
Lets cut through the jargon, like earth loops and earth impedance and get
right down to the source of Hum.
If you have one Guitar into one effects pedal into one amp, you won't get
hum. Although your effects power supply is connected to the mains, it
won't be connected to the mains earth. Therefore, your precious guitar
signal has just one path to ground. Through the screen of your leads into
your amp and through to the mains ground. No problem... All will be well.
The problems occur when you have more than one path to ground for your
signal. Using two amplifiers has always been an issue, because they both
MUST be connected to mains ground.
The GigRig Pro 14 has a very special output for your second amplifier, or
any other earthed equipment.
Only use output 2 when you have already used output 1. Now, Output 2 will
not only prevent hum it will also give you, and your equipment, protection
from over 1000V from front of house or other equipment mains faults.

Phase Switch.

Again, cutting through the techno jargon, with the same sound going to
two amplifiers of different models, the amplifier speaker cones could be
both moving forward at the same time or one may be moving forward
whilst the other is moving back. If this occurs then, when the sounds mix
in the room, they can cancels at some frequencies and positions giving a
reduced and unpleasant tone.
On the Pro-14, you will find a small button next to the isolated output
(Out 2). When this button is pressed 'in', Out 2 will stay in phase with Out
1 and when the button is out, yes you guessed it, Out 2 is then out of
phase with Out 1.
When you have set the phase correctly, you can then swap your two
amplifiers over, without causing a phasing problem.
The GigRig is a 'True Phase' switcher meaning that the signal that comes
out the end is the same phase as the signal that goes into it regardless of
if you choose the Pre-Buffer or Post Volume features.
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