peshewah Posted October 7, 2015 Share Posted October 7, 2015 I sent in a Dayton SA230 amp to Parts express for repair after a lighting strike because of a hum. It was under warranty. I talked to the repair guy and he said he seen nothing wrong with it and it played fine. I got it today, hooked it up, the hum is there. The more I turn up the gain the louder the hum. I don't have time to mess with it tonight but I will tomorrow. Can anyone give me any tips on what I might try or change out? Thanks for any response. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted October 7, 2015 Share Posted October 7, 2015 Tried a different cable? Does it hum without the cable hooked up? Quote Link to comment Share on other sites More sharing options...
Max2 Posted October 7, 2015 Share Posted October 7, 2015 (edited) I sent in a Dayton SA230 amp to Parts express for repair after a lighting strike because of a hum. It was under warranty. I talked to the repair guy and he said he seen nothing wrong with it and it played fine. I got it today, hooked it up, the hum is there. The more I turn up the gain the louder the hum. I don't have time to mess with it tonight but I will tomorrow. Can anyone give me any tips on what I might try or change out? Thanks for any response. Start unplugging anything around it and see if you can locate interference. Don't forget the cable or Sat coax lines too. Can come from a wall outlet as well or bad power strip etc. etc. Start an investigation Edited October 7, 2015 by Max2 Quote Link to comment Share on other sites More sharing options...
teaman Posted October 7, 2015 Share Posted October 7, 2015 May be a ground loop issue. Quote Link to comment Share on other sites More sharing options...
peshewah Posted October 7, 2015 Author Share Posted October 7, 2015 I unhooked the RCA cable and the hum stopped. You think its the cable or the receiver. Naturally I will try the cable first. I have a Mono price cheapo RCA cable. Is one any better than the other? Oh yes, thank for all the help and quick reponse. You guys are the best Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted October 7, 2015 Share Posted October 7, 2015 My guess is the cable. Probably a shield problem. Quote Link to comment Share on other sites More sharing options...
peshewah Posted October 7, 2015 Author Share Posted October 7, 2015 Well hell I don't know for sure. I tried 2 other RCA cables with no luck. I took a power cable from my cable drawer and cut the ground off and the hum went away. Its plugged into the a power strip, is my house going to burn down? Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted October 7, 2015 Share Posted October 7, 2015 You have a ground loop hum. Have you tried plugging all components into the same socket? Quote Link to comment Share on other sites More sharing options...
peshewah Posted October 7, 2015 Author Share Posted October 7, 2015 Not yet. Its my son's room and he is talking to a girl so I'm not wanted. I will give it a shot tomorrow. What bothers me is it worked fine before the lighting strike. No hum, dead quiet Quote Link to comment Share on other sites More sharing options...
Max2 Posted October 7, 2015 Share Posted October 7, 2015 I had a low level hum that would quit when I used a ground lift plug on my amp. I tracked it down to a Direc TV coax cable that ran from my female wall outlet to my DTV Receiver. If I tightened the cable all the way on the wall outlet, I had a hum. If I loosened it slightly it went away and didn't change the Sat picture or signal. Weird stuff. I figured a new connector might fix it, but I just left it alone and it never came back. 1 Quote Link to comment Share on other sites More sharing options...
teaman Posted October 7, 2015 Share Posted October 7, 2015 Consider yourslef lucky. After a lightning strike at my FIL's house it fried all of his Denon/Paradigm gear... 1 Quote Link to comment Share on other sites More sharing options...
peshewah Posted October 7, 2015 Author Share Posted October 7, 2015 I couldn't find were the hum is so I guess I will keep what I have. I painted the cabinet. The pictures do it no justice. It turned out good. I will try to post a picture Quote Link to comment Share on other sites More sharing options...
jason str Posted October 7, 2015 Share Posted October 7, 2015 The worst place for your amp is next to the driver, put it in your audio cabinet with the rest of your gear, doing so and using the same ground as everything else in your system may fix your problem. Good looking little sub. Quote Link to comment Share on other sites More sharing options...
peshewah Posted October 8, 2015 Author Share Posted October 8, 2015 Will do. Thanks for the info Jason. I will clear a spot out for it tomorrow. I learn a lot from you guys Quote Link to comment Share on other sites More sharing options...
babadono Posted October 15, 2015 Share Posted October 15, 2015 Have you tried eliminating the power strip? Or a new power strip? Does power strip have "overvoltage/surge protection"? I also find it very curious that you had no problem until there was a lightning storm and now you have a ground issue. Sorry for being late to this thread 1 Quote Link to comment Share on other sites More sharing options...
westom Posted October 16, 2015 Share Posted October 16, 2015 (edited) I took a power cable from my cable drawer and cut the ground off and the hum went away. Its plugged into the a power strip, Your strategy is flawed. You are trying to identify the one defective part rather then first identify the ground loop. For example, A may be connected to B, which is connected to C, which also has a connection to A. Remember, every wire in every cable is an electrically unique connection - even unique from other wires in the same cable. A ground loop is a current. In this current the current goes from A to B to C to A. You cur of the safety ground prong. Therefore disconnected a connection from C to A. Loop broken. But the defect still remains in B. Define every connection that is part of the loop. IOW long before even trying or considering a repair, first and only identify what exists. Identify every wire that may be part of that loop. Fixing it comes much later. BTW, ignore any recommendation that is not based in basic electrical knowledge - such as that protector. Protector does absolutely nothing until 120 volts well exceeds 330 volts. Your ground loop is maybe single digit volts. Fewer who understand ground loops would know that. Edited October 16, 2015 by westom Quote Link to comment Share on other sites More sharing options...
babadono Posted October 18, 2015 Share Posted October 18, 2015 Yea but the lightning strike could have partially damaged the surge protector devices in the power strip(if it has them), now causing a small current to flow to ground that was not flowing before the lightning strike. That is what they are there for, to get damaged instead of your expensive equipment. This is not rocket science but it is electrical engineering. Anyway that is why I wanted to know if the power strip had surge protection and if it did has the OP tried eliminating or replacing it. Quote Link to comment Share on other sites More sharing options...
westom Posted October 18, 2015 Share Posted October 18, 2015 . That is what they are there for, to get damaged instead of your expensive equipment. Any protector damaged by a surge was undersized and ineffective. Effective protectors work during microsecond currents. And remain functional after every surge. Any protector that 'sacrifices' itself is how near zero protectors are promoted to naive consumers. No effective protector protects by failing .. after a surge has done damage. If a protector is leaking current, then its protector part degrades quickly into a short circuit (blowing a fuse) or into an open circuit. Either way, it does not explain a ground loop. OP should identify the ground loop (A connected to B connected to C connected to A) before accusing one part only on speculation - ie a protector. Quote Link to comment Share on other sites More sharing options...
westom Posted October 18, 2015 Share Posted October 18, 2015 (edited) deleted Edited October 18, 2015 by westom Quote Link to comment Share on other sites More sharing options...
babadono Posted October 19, 2015 Share Posted October 19, 2015 . That is what they are there for, to get damaged instead of your expensive equipment. Any protector damaged by a surge was undersized and ineffective. Effective protectors work during microsecond currents. And remain functional after every surge. Any protector that 'sacrifices' itself is how near zero protectors are promoted to naive consumers. No effective protector protects by failing .. after a surge has done damage. If a protector is leaking current, then its protector part degrades quickly into a short circuit (blowing a fuse) or into an open circuit. Either way, it does not explain a ground loop. OP should identify the ground loop (A connected to B connected to C connected to A) before accusing one part only on speculation - ie a protector. I stand by my post as a POSSIBILITY. As in "if it happens it must be possible". IF there was a surge protector in circuit when the lightning strike occurred and now there is a hum problem it must be eliminated as a POSSIBILE cause of the NOW occurring problem. This is pretty standard troubleshooting protocol. JEESH. Quote Link to comment Share on other sites More sharing options...
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