code: public synchronized void setBalance(float balance)
  	{
  		if (currentBalance != balance)
  		{
  			currentBalance = balance;
  		    if (sourceLine!=null && sourceLine.isControlSupported(FloatControl.Type.BALANCE))
  		    {
  		    	FloatControl balanceControl = (FloatControl)sourceLine.getControl(FloatControl.Type.BALANCE);
  		    	if (balance <= balanceControl.getMaximum() && balance >= balanceControl.getMinimum())
  		    		balanceControl.setValue(balance);
  		    }
  		}
  	}
docs: Set the Balance of the sourceLine
  @since 01.11.2008
  @param gain