Northshore Posted March 31, 2005 Share Posted March 31, 2005 Recently got all the equipment set and system going and now I am in the process of tweaking. I am running Adcom Pre/Pro setup with RF 7's, RC 7, RW 12 and RS 35's. I am getting a hum through the system, I have disconnected the cable from the HD box to no avail. I have disconnected the Sub, changed over to a non polarized plug and still I have the hum. I would add that I have always had some type of A/V receiver and this is my first foray into the seperates. Is this just part of owning a seperate amp? or can you folks give me some things to try? Thanks Quote Link to comment Share on other sites More sharing options...
minn_male42 Posted March 31, 2005 Share Posted March 31, 2005 i would recommend trying a "cheater adapter" to switch the three prong plug to a two prong plug to break the ground loop in the power circuit. i have two separate amps in my system - one has a "ground-lift" switch.... throwing that switch eliminated the hum on that amp.... the other one i used the "three-prong to two-prong" adapter and the hum disappeared on that channel.... lifting the ground on your signal paths may or may not solve the problem... but breaking the ground loop on the power cable should work for sure... Quote Link to comment Share on other sites More sharing options...
SteelerFan Posted March 31, 2005 Share Posted March 31, 2005 You have run into the exact same issue I have. Trying cheater plugs did me no good. First be sure to isolate where in the system the hum starts. That means starting with your amp by hooking up your speakers and nothing else. In my case there is no hum there but as soon as I hook up the preamp I get the hum. I suspect being able to use balanced interconnects might cure it. Unfortunately while my amp supports balanced connections, my preamp does not. I may have some grounding issues with my house electric and should probably call an electrician to check it out. The fact is I'm pretty much used to the hum now and it doesn't really bother me that much. One day after I've finally made all of my upgrades I might try these: http://www.jensen-transformers.com/ci2rr.html Good luck. Quote Link to comment Share on other sites More sharing options...
KungFuNat Posted April 2, 2005 Share Posted April 2, 2005 go on PS-audios website, they have a hum diagnostic tool on there called "humbusters" it will take you through several steps on how to track down the source of the hum, then give you a diagnosis. Quote Link to comment Share on other sites More sharing options...
PYRO Posted April 2, 2005 Share Posted April 2, 2005 Cheater Plug worked for me. Quote Link to comment Share on other sites More sharing options...
minn_male42 Posted April 2, 2005 Share Posted April 2, 2005 ---------------- On 3/31/2005 5:39:23 PM SteelerFan wrote: You have run into the exact same issue I have. Trying cheater plugs did me no good. First be sure to isolate where in the system the hum starts. That means starting with your amp by hooking up your speakers and nothing else. In my case there is no hum there but as soon as I hook up the preamp I get the hum. I suspect being able to use balanced interconnects might cure it. Unfortunately while my amp supports balanced connections, my preamp does not. I may have some grounding issues with my house electric and should probably call an electrician to check it out. The fact is I'm pretty much used to the hum now and it doesn't really bother me that much. One day after I've finally made all of my upgrades I might try these: http://www.jensen-transformers.com/ci2rr.html Good luck. ---------------- you might be able to solve the problem by using an RCA to XLR cable between your preamp and amplfier..... try it with the #3 pin disconnected... most unbalanced to balanced cables/adapters will tie pins #1 and #3 together.... lifting (or disconnecting) pin #3 might solve your hum problem.... good luck! Quote Link to comment Share on other sites More sharing options...
SteelerFan Posted April 3, 2005 Share Posted April 3, 2005 Thanks Russ, I didn't even know there was such a thing as an RCA to XLR cable. I'll investigate further. Quote Link to comment Share on other sites More sharing options...
minn_male42 Posted April 3, 2005 Share Posted April 3, 2005 ---------------- On 4/3/2005 5:00:55 PM SteelerFan wrote: Thanks Russ, I didn't even know there was such a thing as an RCA to XLR cable. I'll investigate further. ---------------- http://www.cablestogo.com/product.asp?cat%5Fid=2029&sku=40046 Quote Link to comment Share on other sites More sharing options...
SteelerFan Posted April 4, 2005 Share Posted April 4, 2005 Thanks again Russ, I've added the page to my favorites and will wait patiently until 4/23 when they become available. Quote Link to comment Share on other sites More sharing options...
dkp Posted April 5, 2005 Share Posted April 5, 2005 EDIT-removed post due to bad info in my question... Quote Link to comment Share on other sites More sharing options...
minn_male42 Posted April 5, 2005 Share Posted April 5, 2005 ---------------- On 4/4/2005 4:50:19 PM SteelerFan wrote: Thanks again Russ, I've added the page to my favorites and will wait patiently until 4/23 when they become available. ---------------- do a google search for "RCA XLR CABLE" and you will find many online sources selling those cables Quote Link to comment Share on other sites More sharing options...
Northshore Posted April 23, 2005 Author Share Posted April 23, 2005 After lots of research and trial and error, we have located the hum in my system. The projector was the culprit and with a cheater plug we were able to eliminate the annoying hum. Thanks everyone for the input. Quote Link to comment Share on other sites More sharing options...
dragonfyr Posted April 23, 2005 Share Posted April 23, 2005 I think Minn_Male's XLR to RCA is a good general solution for induced hum if you can't simply remove the source, as the XLR third pin is connected to the braid - thus providing a grounded shield, but avoiding ground loop by 'floating' on the RCA end. This is an optimal way for any system interconnect to be configured - with the ground conductor connected on the end attached to the pre-amp, while the ground is left floating on the other end, thus creating a star ground relative to the pre-amp and providing RF shielding of the cables without providing a path for ground loops via the RF signal path... Quote Link to comment Share on other sites More sharing options...
SteelerFan Posted April 23, 2005 Share Posted April 23, 2005 Question: which one is the #3 pin in the XLR connector and how does one go about disconnecting it...by just yanking it out? Sorry for my ignorance. Quote Link to comment Share on other sites More sharing options...
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