We purchased a new gas range after it was installed when we turned on a burner we got a loud hum. We had a repair man came out and he said we needed a new regulator, it was installed and the range still hummed. Sears then replaced the range after it was installed, you guessed it it still hummed. they then replaced that regulator and it still hummed. We had a plumber come out twice to check our gas line. Once before the second range and once after the second range, two different companies. They said our gas lines and supply were fine. We returned the range and purchased another make and model. The burners still hummed. I then replaced the shut off valve,and turned down the gas supply to the range. The humming is not as often but still occurs. Are we safe? Does anyone have any ideas or a better solution to the problem. The house is 90 years old if that makes any difference.