bacevedo Posted October 2, 2001 Share Posted October 2, 2001 Hello All! I have a KSW 12 hooked up to a Denon 3802 via the sub out on the receiver. I was using Radio Shack Gold Series interconnects, including a 20 foot audio cable for the sub. I recently purchased Acoustic Research Pro Series interconnects all around, including their 25 foot sub calbe. First off, these cables are pretty nice, especially for the money. I am really impressed. But, I had a problem with the sub cable. It is directional (so they say) and has an arrow pointing in one direction. They say to put this into the input, so I put this on the input of the sub. I guess (by reading on the net) that it has something to do with the way it is grounded. Who knows. Anyway, after using this cable, everytime I turn off my ceiling fan, my sub thumps. I tried everything I could think of to get rid of it. Unplugging the cable from the sub gets rid of it. Even just having the cable plugged in to only the sub gives the thump. No cables plugged in = no thump. RS cable plugged in = no thump. So I reverted back to my RS cable, and now I have no thmp when turning off the ceiling fan. It's like the cable is picking up the RF from the fan turning off and sending it to the sub. My question to everyone is, why did this happen? I supposedly got a high quality, shielded, specific for sub cable. Is it a defective cable? Should I exchange it or just return it? I heard no audible difference between my RS and AR cable, but I like the build quality and look of the AR cable, plus the connectors are much easier to work with on the AR cable. I am also anal, and like to have all of my cables be the same. Another note is that the Y-Cable I got is also going back. It seemed to have a short in it. When I would jiggle it, it would cause a loud hum (like a ground loop hum). Very weird. I am just wondering why this would happen. The cable is twisted pair, balanced and all that jazz. So let me know why it would do this. Thanks, Bryan ------------------ "... But Honey - I promise this is the last thing I will have to buy for the Home Theater" Mistubishi VS60603 60" RPTV Denon AVR 3802 Receiver Denon DVM 1800 DVD Changer JVC 3600U SVHS VCR RCA DirecTV Satellite Tuner Klipsch RB5 - Mains Klipsch RC3 - Center Klipsch RCW3 - In-wall Surrounds Klipsch KSW12 - Sub (hopefully an RSW12 whenever they come out!) Monster Power Conditioner HTS1000 Acoustic Research Pro Series Interconnects Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted October 3, 2001 Share Posted October 3, 2001 Did you try reversing the direction in which the AR cable was connected? If the shield ground is floating on one end and grounded on the other it might react differently depending upon whether the ground connection is on the receiver or the amp. I'll refrain from pointing out a couple of Murphy's correlaries, those being "If you mess with a thing long enough, you'll break it" and "If it ain't broke, don't fix it!" I always LIKED the RS Gold Series cables... ------------------ Music is art Audio is engineering Quote Link to comment Share on other sites More sharing options...
bacevedo Posted October 3, 2001 Author Share Posted October 3, 2001 Yeah Ray - I tried that, as well as all kinds of possible combinations. Here is what I did. Unplugging the cable from the receiver and only leaving it plugged into the sub - thump. Reversing the cable while plugging into receiver and not plugging into receiver - a little less thump, but still there. No cable plugged in at all - no thump. RS cable plugged in any which way - no thump. Plugged the Sub power cord into my Monster power conditioner, with the AR cable - thump. No matter what I did, with the AR cable the thump was always there. I posted this on HomeTheaterForum and someone there said that it is because of the floating ground. The fan is causing a difference between voltages, and with no common ground, it cause a thump. Kind of above my head. But what I wanted to know was whether this was a defective cable, or just a design flaw in the cable when used in my setup. I am thinking that this is a design flaw, and getting another cable will not solve the problem. I have decided to stick with the RS cable for the sub only. My other cables are all still the AR cables. It worries me though that the audio connectors on them are also directional (with no ground on one end). Even though I haven't heard anything, I have only had them for a little while, and would rather return them now if they are going to cause a problem in the future. Bryan Quote Link to comment Share on other sites More sharing options...
boa12 Posted October 3, 2001 Share Posted October 3, 2001 bac only thing i can think is do you have a ground lifter (cheater plug) on the sub ac plug? if so try without or if not try with a cheater plug on. if it's a grounfd loop thang, this may work. Quote Link to comment Share on other sites More sharing options...
bacevedo Posted October 3, 2001 Author Share Posted October 3, 2001 Isn't a cheater plug only for a 3 prong cord? The cord on my sub is a 2 prong type, so I don't think the cheater will work for it. However, it does have one prong bigger than the other, does a cheater plug let you reverse the polarity of that, too? I also feel that if I have to use a cheater plug, then something is wrong. I won't settle for that! So instead, I will just use a different cable that doesn't exhibit this weird behavior. Bryan Quote Link to comment Share on other sites More sharing options...
boa12 Posted October 3, 2001 Share Posted October 3, 2001 bryan, never mind the cheater plug then. it shouldn't allow to reverse polarity either. electric wiring very tricky in audio even for the "electricians". i get bad electrical noise in my computer sound system when it's on & i turn the ceiling fan on/off. & it's continuous noise til i turn off the amp. they on same circuit. only other solution i can think of would be to put the sound system on a different dedicated circuit apart from everything else like fans, dimmer switches, etc. probably much cheaper just to use the rat shack cable though. Quote Link to comment Share on other sites More sharing options...
bacevedo Posted October 5, 2001 Author Share Posted October 5, 2001 Update: I am having www.discounts-n-deals.com send me a new set of cables to try. I talked with Dave there, and he is a pretty knowledgeable guy! He said it definitely shouldn't do that for a $28 cable, if my $10 RS cable doesn't! He thinks that maybe the shield was lifted on both ends and was defective. So they are sending me out some new ones to try, and paying for return shipping on the bad ones! I highly recommend this site for the AR Pro Series Cables. Good prices and great service! I will post my results when the new cables arrive next week. Bryan Quote Link to comment Share on other sites More sharing options...
RossVTaylor Posted October 7, 2001 Share Posted October 7, 2001 Bryan, You should be able to diagnose the floating-ground aspect of the problem pretty quickly, to see if that's the problem. Using the AR cable, run another wire from a metal part (like a amp panel screw) to your Denon's ground screw (near the antenna jack). You can use any type of wire to do this. With both units grounded together, see if you get the thump from the fan now. If not, then your setup just "doesn't like" the lack of a full-length ground connection in that floating ground AR cable. You could then either connect the other end of the ground conductor in the AR cable (if there's enough there to solder), or you can revert to the RS or another cable with a full-length ground, or you can run an independent ground wire from sub to receiver. Best of luck, Ross ------------------ "Time flies like an arrow. Fruit flies like a banana." Quote Link to comment Share on other sites More sharing options...
bacevedo Posted October 15, 2001 Author Share Posted October 15, 2001 OK - as promised an update. I got the cables in today. I hooked them up - and no thump when I turn the ceiling fan off. So it appears that it was just a defective cable! Thanks for all the input, as it was educational! Bryan Quote Link to comment Share on other sites More sharing options...
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