humming through speakers

[admin_exported]

Hi All, I recently moved house and got some epos m5 speakers to go with my cambridge 640 v2 amp / cd player. When switched on, I am getting a hum through the speakers, and it gets worse when playing music.

I have the TCI baby constrictor 4 way plug, and merlin power cables, as well as chord silverscreen speaker cable.

I have tried moving the power leads around, but still the damn hum does not go away, and like I say, it makes a worse noise when playing music.

Is it the cables being to close together, about 3 inches to the one speaker run only, and no where near the other one, or is there something wrong with the speakers?

It's now getting on my bloody nerves and driving me barmy!

Your thoughts would be greatly appreciated....

 

[John Duncan]

Are the cd and amp on a rack and separate, or is one sitting on the top of the other?

 

[Anonymous]

They are on seperate shelves of an atacama rack.

I pulled out the power lead from the amp, and the humming went. Also, I have the tv and dvd player into the 4 way plug as well.

Should I disconnect everything and just have the amp and speakers connected, then add things one at a time?

Your help is needed, as even the missis notices, and she can't tune it out of her listening....

 

[John Duncan]

Well obviously turning the amp off will stop the humming, but what you suggest makes sense - remove each in turn - if it's none of the components plugged directly into your 4-way, look further afield, as it could be something like a fridge or fan or something. Also, you don't have one of those "ethernet over the mains" things do you? They're the work of the devil.

 

[Anonymous]

I will try that when I get home. I don't a computer in the house (strange in this day and age I know!), but have a qed ttv lead for the tv.

I will take all of the stereo connections appart and go from there...

I thought it could be my mobnile phone charger, but it wasn't that! I might just rip the house apart and build from scratch!

 

[Thaiman]

I think problem could be Palsma TV & Sky combo. Unplugs them and remove power leads away from the system....should work but then you will end up with no Telly!

 

[Anonymous]

I have a 32 inch sony tv and samsung dvd player in the 4 way socket, so will try and remove them.

I have 2 double sockets in the wall, so will try moving them both, or one of them to the other sockets. I had a lamp into the wall sockets as well, tried removing that, and apart from not being able to see, the hum was still there.

Will try it all when I gwt home from work at 5pm.

Cheers for your replies

 

[Anonymous]

I undid all the leads and interconnects, and re attached them one by one, and still had the humming. ÿI moved the speaker cable miles away from the power leads etc, then tried different sockets, but still the damn humming was there!!

ÿ

I then took the fridge out of the socket, the microwave etc, and all other appliances around the house, and still it was there. ÿI tried other speakers and the humming did not go away.

ÿ

I then went upstairs and noticed that the stereo in the bedroom has the same bloody hum from the speakers.

ÿ

Any information on where to go next would be greatly appreciated, as it is driving me to drink now!!ÿ

ÿ

thanks,

philÿ

 

[Anonymous]

I had the same problem with my amp. I tried everything you did and in the last place I replaced an interconnect between control-amp and power-amp. The humm was gone. Since this is not your case, you should try to put your amp in another room (or maybe in another house). Also try to replace the speaker cables (or did you do that already?)

Nejc

 

[Anonymous]

seduct10n:Any information on where to go next would be greatly appreciated, as it is driving me to drink now!!

Well, if you've tried isolating the problem by stripping away the components, and if you've got the humming in your other system, it sounds like the source of the hum is the mains. Probably the easiest thing to do is to take your amp and speakers round a mate's house and try them there. That way, you'll be sure these components aren't faulty. Assuming it is the mains, I'm not sure what you can do...

 

[Anonymous]

It does look like the mains.

If it is then you could try an uninterupted power supply ... maybe even a cheap £30 one may work - I think the mains may be used to continuously charge a battery while your equipment continuously draws current from the battery. Never used one so not sure if thats actually how they work ... can anyone shed any light on that?

Edit: most UPSs only trigger battery operation on loss of power so will not solve your problem, I think you may have to resort to a mains conditioner of some sort - try something affordable on home demo first to see if it helps (although I would have thought that the constrictor would have been enough). Hopefully its not masses of RFI that are generated in your home that are interfering with everything.

 

[matengawhat]

what interconnects are you using i have an arcam solo movie and alpha 8p connected with merlin chopin interconnects and get a hum - tried 3 different sets from my old system all chopin all hum - changed to old cambridge audio interconnect hum gone!!! Changed back to merlin reappears

 

[Anonymous]

I am using the chord crimson and chord silver screen speaker cables. Will try an old VDH the name interconnect tonight and see if it makes any difference. Will let you all know if it has any difference at all.

Cheers for your replies....

 

[Anonymous]

If you get the hum with just the amp connected to the speakers then you might try grounding the amp as a next step.

BTW it's also worth checking that there is not an appliance in the house wired up wrong way around with the live and neutral back to front. Also if you have any low voltage or fluorecent lighting make sure it's turned off. When you do the next set of tests. You might be getting hum from a faulty choke or starter.

If you live in a semi or a flat then it might be eminating from next door's kit.

Does it vary if with amp volume BTW?

 

[Anonymous]

I have already ripped the house appart, and switched all appliances off etc.

How would you ground the amp, would you earth it to the rack?

I have just moved into a 3 bed detatched, so the next house is about 30 yards away. I only did this as my old neighbours really did not enjoy listening to my music, but when I told the missus it was to upgrade, she was over the moon! It's good to keep these small things from the other half, just like the new amp I want to buy in bout 6 months time, when I'm not skint...

It is a low hum when just having the amp on, but increases when playing CD's, but if you turn the volume up, it does not get louder the louder you play it.

 

[Anonymous]

You can get a reasonable ground on the amp by just touching the metal case. There might even be a grounding contact on the back. If you touch this and the hum is attenuated then that will be a clue. If it is try running a wire to earth (a water pipe will do the trick usually.)

Speciffically if the amp is on and speaker only are connected (i.e. all usual sources switched off and the interconnects unplugged from the amp) can you still hear the hum?

Are you sure the hum is coming only from the speakers? Get your ear close to the amp and see if you can hear it huming (again with all interconnects pulled out of the amp but with the speakers connected).

Is there any big industry near you? Factory, Hospital, big office block etc?

 

[Anonymous]

Yeh, it hums with just the amp on and the speakers plugged in.

I live near a huge shpping centre called merry hill, and there are lots of factories near by. I am hoping that I don't have to go shut them down etc just to enjoy my hifi, as they may not want to close down for me ;-) can't see why!

I will try the ground contact on the rear when I get home from the gym later.

 

[Anonymous]

It's not immpossible that you are getting the hum due to big inductive loads from near by factories. If this is the case then the only answer will be some sort of power conditioner.

 

[Anonymous]

I have just spoken with Richer sounds and then their old maintenance guy, and he thinks it is due to the output devices / transistors being faulty.

It is out of warante and it is going to cost about £90 to £100 to fix!!!

Does anybody know if this is a problem with the Cambridge amps and if so, is there a cheaper method to fix it???

 

[Anonymous]

OK but in an earlier post you mentioned you had the problem on another system. I'd check everything else first.

If the amp is really knackered then buy a new one rather than fix the exisitng IMHO.

 

[Anonymous]

It might be worth trying a Tacima mains conditioner on there first

 

[Anonymous]

I have the TCI baby constrictor 4 way, which kicks the tacaima into touch, will try everything else tonight and then go from there.

Cheers for all you replies

 

[Anonymous]

I had a similar problem a few years ago. ÿIt turned out to be due to a 4-way power block (in a different room, used for computer kit, unconnected to the hi-fi) whcih had been wired incorrectly; the neutral was connecting to ground and vice versa, so the current was "returning" to ground. ÿThe computer was working fine. ÿVery strange stuff, electricity! ÿCorrecting this fixed the hum problem.

Now, I'm not suggesting that your problem is anything as bizarre as this - but I certainly think you should check out the mains (and perhaps the grounding in particular) in some way. ÿAnd if you have not already done so, you should try disconnecting (not just switching off) *everything* else in the house, garage, etc. ÿAs others have pointed out, the fact that you are getting the same problem on your other system is a big clue. ÿI am not a great fan of mains conditioners, but you might wish to look at some of the information on the Russ Andrews website.ÿ

 

[Anonymous]

I heard of humming through a comb and paper, tickles your lips though!

 

[Anonymous]

its mains bourne.

the richer sounds technicians are stupid. I sent a smoking amp back 5 times before they let me plug it in while in the store to smoke it in front of them. Only after this apparent breach in health and safety (lies) did they believe that pressing the mm button made it smoke above number 4 on the volume. Hardly complex testing is it. Its like the question of how bad outputs in the downstairs system can make the upstairs one hum. All they have realised is the noise is entering the finals, so i guess they spent at least a few confused years at college. ignore them.

do you have a cooker outlet with a socket? its possible to kill all other circuits at the fuse board then. that will deal with hidden loft signal boosters and the like. just leave the cooker circuit live and use an extension to power your amp only. It and the cooker will be the only devices on this way.

mains noise is not something i can test for and fail factorys on im afraid. However the electric board will track down major offenders in some circumstances as it stresses there supply network. Bad power factors from inductive loads running without correct lead to financial penalties for buisnesses. There bill will go up as the distribution companys have to sort out there mess. Your going to need a scope to see the noise though.

scope... hmm. if its audable noise then pc scope software used to monitor inputs to a sound card would do. you would wrap a wire round a mains cable for some inductive coupling, then stick said wire into the mic socket and apply the mic boost option in your pc's audio rack. No pc though...

whats the hum? mains 50hz rumble or high frequency? high frequency noise from switching power supplies is getting more common. It can get into the cables through electromagnetic coupling, and take down data highways in some cases its so noisey.

Dont look to your neighbours, look 3 away. 3 phases as you know, and you get one, your neighbour another, his another, then bacxk to yours alternationg down the street to save wars between neighbours over such issues. Just have a little look.

Is it 24/7 ? most places shut at some point. Patterns can help locate problems just by keeping notes.