This paper will detail a method I use and support as a solution to sound system power noise problems.  My system uses this solution and I run sound and lighting from the same power source. NOTE:  this information is for USA electrical systems.  It will work for European situations as well but I do not detail that configuration.

OBJECTIVE

The objective of The Christronix Method of power distribution is to provide clean power to sensitive equipment.  This sensitive equipment is defined as low level audio gear: mixers, effects, EQ's etc.

 The objective is accomplished by:

- Isolating the mains power shared neutral conductor
- Creating a new safety ground reference point
- Phase lead noise reduction via transformer noise rejection.

APPLICATION: THE METHOD…

The core of The Christronix Method is the use of a step down isolation transformer.

Use a 208/250 VAC input, 125 VAC output Isolation Transformer.  Two mains power phase leads are connected to the input.  The mains power or common safety ground is connected to the secondary output bus connection AND to one secondary output lead to create a neutral conductor.  See figure 1  Click Here

The selection of the isolation transformer is up to your budget. The more $$ the better.  See below:

-A basic step down transformer will provide a lot of help.
This transformer will have a limited band pass with relation to frequencies conducted through the transformer.  This fact reduces audible noise. This transformer may have leakage between the windings that affects the noise rejection..

-Transformers with additional isolation between windings will help a bit more.
These transformers have low leakage between the windings.  This creates a lower band pass and less noise conduction.

-You can also use a stabilized isolation transformer.
Voltage stabilized transformers use various means to level output voltages.  These transformers can help keep voltage sensitive equipment happy as well as supply clean electrical power.

Select an isolation transformer that has enough capacity to power the FOH gear and any other sensitive gear you need to power.

NOTE: IT IS USUALLY UNNECESSARY TO PROVIDE ISOLATED MAINS POWER TO AUDIO POWER AMPLIFIERS.

Audio Power amps usually have quite enough power source isolation from noise.  Linear power supplies have nice big transformers.  Switching power supplies use other methods to produce a similar isolation.

Audio Power amps usually also are properly safety grounded.

CAUTIONS

It is necessary to be safe.  Always connect and maintain connection of the safety ground connection. A serious failure in a step down transformer, while rare, can cause elevated voltages to appear on the output of the transformer.

It is allowed and possible to float the output of the isolation transformer, meaning you need not connect one output lead to the safety ground to create a ground referenced neutral conductor.  While this is allowed and possible, I do not recommend it.  A serious failure of the transformer could apply elevated voltages to the output of the transformer.

ALWAYS MAINTAIN SAFETY GROUND CONNECTIONS

DISCLAIMER

This information is offered as a suggestion.  Use this suggestion at your own risk  I assume no liability for your implementation of this method.