Fizzlemizzle Posted January 31, 2010 Share Posted January 31, 2010 So I'm building a DIY sub and I might have an issue. I hooked up my Dayton RSS390HF 15" in free-air to listen at low level and check out the quality. I would be surprised if i gave it more than a watt or two and with the input gain at 50% on my Audiosource amp three it sounded great. However, when I turned the gain to around 75% and above I got an electrical sounding hum from the driver. This is in bridged mono, I'm sure I've connected everything right. The hum was present above around 50% in both my shielded sub RCA cable and non-shielded RCA cable. The amp is rated at 400 watts mono at 8 ohms but I've read many people on audioreview using it to power subs and some expert review was using it to power 4ohm speakers. The hum is not present with the gain maxed going to my Mains. Do you think this is a ground loop issue? That is what I'm learning towards. Thanks guys. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 31, 2010 Share Posted January 31, 2010 A cheater plug will tell you if it's a ground loop hum but it doesn't sound like one. A ground loop hum is noticeable even when the amp and preamp gain are all the way down. Have you tried it in anything other than free air? Quote Link to comment Share on other sites More sharing options...
Fizzlemizzle Posted February 1, 2010 Author Share Posted February 1, 2010 Just tried it in free-air. Cheater plug is just the adapter without the ground, yeah? That would be okay to put into a battery backup with surge protection, correct? Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 1, 2010 Share Posted February 1, 2010 Just tried it in free-air. Cheater plug is just the adapter without the ground, yeah? That would be okay to put into a battery backup with surge protection, correct? Yes, it's the 3 female to 2 male plug (minus the ground prong). Use it for testing to help you find out what your root problem is, then correct your root problem. I still don't think it's a ground loop issue, but the cheater will tell you for sure. You can also mount the driver on a scrap piece of plywood and see if the noise is still there. Quote Link to comment Share on other sites More sharing options...
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