Members drenwick Posted November 15, 2008 Members Share Posted November 15, 2008 Our bass player runs a line out of his Ampeg head to an input of our mixer. Last night after hooking everything up, we were getting a low frequency hum that I narrowed down to his input. Changed out the XLR cable and it still did it. This was with his Ampeg OFF. Turned the amp on and the hum went away and everything seemed fine. At the end of the night, he turned it off and got all kinds of weird noise - it was only for a second as he turned it back on immediately until I powered down the rack, but I thought I even heard radio interference. Any possible explanations? Thanks in advance for your help! Link to comment Share on other sites More sharing options...
Members gspointer Posted November 15, 2008 Members Share Posted November 15, 2008 I have never tried because your power on/off procedures are wrong. By having the channel active when the bass player turns on his amp, you are introducing a potentially dangerous spike into the PA. Likewise when you turn off, PA or channel mute first, then signals to the PA. BTW, I wouldn't worry about odd noises when the amp is off. Link to comment Share on other sites More sharing options...
Members bass4one Posted November 16, 2008 Members Share Posted November 16, 2008 I have never tried because your power on/off procedures are wrong. By having the channel active when the bass player turns on his amp, you are introducing a potentially dangerous spike into the PA. Likewise when you turn off, PA or channel mute first, then signals to the PA. BTW, I wouldn't worry about odd noises when the amp is off. exactly. Link to comment Share on other sites More sharing options...
Members solderjunkie Posted November 16, 2008 Members Share Posted November 16, 2008 My old Mesa Subway Rocket picked up AM radio rather well. It only did it at my house, and only if the air conditioner was "off". Luckily it was an old-timey Gospel station and I could play along. I actually learned a few licks from those flatpickers:thu: Link to comment Share on other sites More sharing options...
Members tylytle Posted November 16, 2008 Members Share Posted November 16, 2008 Grounding issue? Link to comment Share on other sites More sharing options...
Members mrcrow Posted November 16, 2008 Members Share Posted November 16, 2008 earth loop or a radio station..vhf Link to comment Share on other sites More sharing options...
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