[gradojunkie]

hey,

I've got a question about my reciever. I've been getting alot of humming (during moments of silence in the music) from my Kenwood kr-2600 reciever. Is that just because its old? or shoud I get a differentcable or somthing?

(by the way I have grado sr-125s and sr-60s so I dont think that my cans are the problem)

thanks for the help

Junkie,

 

[Melchior]

First disconnect any inputs to the reciever and see if there's any hum. If there is it's probably a problem with the reciever itself. If it only happens when you have a source connected it's likely a ground loop problem. First try to ensure all the equipment is on the same grounding plane, IE: use a good power strip/surge protector to plug in all connected equipment, I mean "everything" that's interfaced through that reciever, including your tv, any video/audio devices. If that doesn't solve it then you'll probably have to go through unplugging each piece of equipment seperately until you find the one causing problems. It's also possible that it's caused by interference from your power cables or a fluorescent light, in which case properly shielded interconnects and shielded powercables (for equipment that has IEC connectors) should help.

 

[LFF]

Well - I truly wish I could help but I am having the same problem with my system. It used to be dead quiet. Then I moved into some new apartments and that's when the hum came in. I purchased an AR surge protector and that did nothing. I disconnected everything, put in the plugs the same exact way, turned off everything except my system, disconnected everything in my apartment, you name it and I tried it. However, ever since the hum started, something else started as well - my apartment lights tend to fade in and out or flicker at time. My only guess is that there is some sort of overload in the power system.

As of yet, I have no solution. I wish you luck in finding a solution to yours though.

 

[Melchior]

Sounds like an apartment wiring issue, or perhaps fluorescent lights/dimmer switches elsewhere in the building. I doubt it'll help, because this sounds like a serious wiring issue where you're living, and I've never used one, but try out the belkin Isolator, the construction looks really nice, and it looks like it has filtering up the wazoo. Just make sure they'll let you return it if it doesn't work, though you may want to keep it anyways as it surge protection may be a good idea in an apartment with power that bad. If that doesn't fix it I doubt any plugin device short of an AC regenerator will do you any good.

Edit: oh, and you might want to use a multimeter that can check AC voltage to check your wall socket, hot-ground should read between 110-125, same with Hot-neutral. More importantly neutral-ground should read less than 0.5 volts. There should also be no DC voltage anywhere. Any signifigant variance on those numbers, especially the Neutral-ground indicates a problem that needs to be fixed at the service entrance. If in doubt consult a real expert, most of my knowledge is taken from reading numerous white papers and pdf files over the past few days trying to figure out fact and fiction when it comes to surge protection and powerline conditioning, so I probably know just enough to be dangerous

 

[rickcr42]

Quote:

First disconnect any inputs to the reciever and see if there's any hum

If there wasn't there will be !

Listening to audio equipment with unterminated inputs (open) is looking for trouble.Terminate the input being tested with a terminating plug then listen for hum.
Check for wires running prarllel with AC cords and funally look for loose RCA Jacks

 

[Melchior]

See what I mean about experts

That reccomendation was based on my own experience though, I've never experienced hum on any amplifier with unterminated inputs before, and used that method when trying to trace hum/noise on my Gilmore V2, which was dead silent with the inputs disconnected. Turned out to be interference from other cables behind my machine, it was fixed by using shielded interconnects and using a shielded powercable for my CRT monitor as well as a bit more care with the cable routing.

 

[rickcr42]

The only way to test/measure any piece of audio equipment is with terminated inputs and outputs.In fact some gear can even be damage by being on but unloaded,some of that in the case of some output transformers where they think there is an infinite impedance blowing the primary windings, a very expensive fix.

when there is hum where there was none before the first question I ask myself is "what has changed" and start there.
If that answer is nothing then it comes down to my next question which is "how old is this sucker" and finally "what in the room/house has changed"

Aging parts can mean open capacitors no longer doing the job,if tubes gear the tubes can be marginal,if nothing has changed either systemic or house wide I just do the old "wiggle the jacks,move cords" until the hum changes in intensity which tells you that is the trouble spot or goes away entirely with a simple interconnect repositioning.

always suspect cables at the front end,the source end, then move towards the output end when checking hum.
It is the gain stages that usually are amplifying something that has gone before the culprit

 

[Melchior]

Thanks for the info on equipment damage when not terminating the inputs. I knew about some tube amps not liking being connected at the out's, but I figured the inputs were pretty safe.