Guest anthony schwar

Advice neaded low hum from speakers

34 posts in this topic

HI i recantly brought a new amp a bow wazoo xl, i have just noticed when there is no music playing a faint hum from both my speakers. I have put it in standby mode still there, i have turned of all my sockets in the house by the fuse box exept the rear sockets that my hifi is connected to still there, i fear the amp neads seeing to, or is it the power as i dont have a conditioner. Nether noticed it before or on any other amp on this system any advice please.

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Is it connected to an adjacent mains socket to the cdp?

Is it affected by the volume control?

Does it still hum with the cdp turned off?

Just thinking there could be an earting issue. Or possibly the caps in the amp psu are getting on a bit.

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Presumably you are absolutely sure that the hum is coming from the speakers drive units and is not mechanical hum being generated by the amps transformer (as it often is with bigger transformers)?

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From what I understand from Bo Christiansen (the designer) Bow amps do that!

I've got a Warlock SE pre-amp and was worried by the low hum through the speakers. Tried it without the pre, different pre etc and it was definitely from the Warlock.

So I contacted Bo who said it was something to do with his zero-feedback design; he also pointed out that it was inaudible when any music was playing, even at very low volumes - so not really a problem as it sounds fantastic!

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Read about earthing somewhere and the artical said you can add more hum with to many earths in the system, also read about taking the earth from all the components and earthing one in the chain but that just sounded dangerous to me. I have a low hum in mt OPen Baffles and im sure its from the pro amp as the hum goes up when i crank the volume up on that amp but as Leonard says its not heard when playing but annoys the crap out of me between tracks, sometimes your mind just wants to concentrate on listening for the hum. Be a lot happier if it was not there so this is an interesting post for me.

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he also pointed out that it was inaudible when any music was playing, even at very low volumes -

That was also the claim for MP3. I have had a similar problem, and although the hum SEEMED inaudible when music was playing, it sounded better when the hum was removed. I do a lot of late night low level listening, so you may not have the same experience. However I would be suspicious of the MANUFACTURER claiming it becomes inaudible; he would say that, wouldn't he?

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Only time I ever had 'hum' (except when I needed a shower :P) was, as Chris says, an unshielded interconnect. It was a VDH First. Changed to Second, which was shielded but not as good sounding, the hum disappeared.

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Is it connected to an adjacent mains socket to the cdp?

Is it affected by the volume control?

Does it still hum with the cdp turned off?

Just thinking there could be an earting issue. Or possibly the caps in the amp psu are getting on a bit.

hi yes it is pluged into a differant socket from the cdp i have double sockets at one end of room one for amp and the other side i use this for cdp i have tried differant power cables it still hums when the cdp is off and the balanced interconects are removed it isnt effected by volume and cant hear it when playing music even at very low volumes

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yes its from the amp somewhere

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i think this is spot on i know i had a bow xl 6 years ago i cant even remember if that had the same prob but your right when music is playing i get no hum even at very low level so it isnt a big prob i just want to make sure ime not doing any damage

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all my cables are sheilded very high quality but worth a go

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hi yes it is pluged into a differant socket from the cdp i have double sockets at one end of room one for amp and the other side i use this for cdp i have tried differant power cables it still hums when the cdp is off and the balanced interconects are removed it isnt effected by volume and cant hear it when playing music even at very low volumes

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yes its from the amp somewhere

If it's possible could you temporarily plug the cdp and amp into sockets next to each other. Sounds daft, but it has worked a couple of times when I've helped people out with hum.

If you put your ear next to the amp can you hear any hum from it?

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no hum from the amp dead silent pluged amp into same double socket still there

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i did change me interconects yesterday from phono to balanced i have some triple insulated A.R.T PHONOS TREID THEM BACK IN THE SYSTEM STILL THERE

THE THING I DONT GET IS EVEN WHEN ITS IN STAND BY I GET IT WEIRD

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Bit stuck for a further suggestion apart from getting the amp looked at. Maybe it's just a feature of the amp. Hopefully not.

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From what I understand from Bo Christiansen (the designer) Bow amps do that!

I've got a Warlock SE pre-amp and was worried by the low hum through the speakers. Tried it without the pre, different pre etc and it was definitely from the Warlock.

So I contacted Bo who said it was something to do with his zero-feedback design; he also pointed out that it was inaudible when any music was playing, even at very low volumes - so not really a problem as it sounds fantastic!

Hi,

If the designer has said that it is a circuit design issue it would seem to me that nothing you can do will cure it.

Of course, some of the ideas expressed here are good practice and it certainly can do no harm to try them

but I feel you will be stuck with the hum.

As an aside, many years ago now, I needed to replace my amp transformer and chose to get an uprated one.

(A huge Toroidal).The hum could be heard all over the house and I tried all sorts of transformer isolating, clamping,etc. without

any improvement.

I then realised that at the same time I changed the Transformer I had slightly rearanged the positions of the amp,

tuner, cassette deck etc. with the amp now at the bottom of the "stack".

As soon as I lifted the amp up off the furnature all humming ceased totally.

It was caused by the top of the furnature cabinet, on which everything was placed, resonating at mains frequency. Simple as that.

I had been at my wits end having tried all of the usual hum cures without anyimprovement.

Rgds.

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If you get it even in standby, then it's the amp itself. Do not under any circumstances mess about with disconnecting earthing anywhere. It's there for a reason.

I very much doubt it's doing any harm, though it could be an indication of a problem with the amp. It suggests something less than ideal within the power suppply section, though whilst it could be a fault, it could similarly be a case of 'they all do that sir'.

Really, it's down to whether it's loud enough to be an issue, or whether you can live with it. It would bug me, I must admit. If you can't hear it when music is playing doesn't mean that it isn't there, just that the music is louder. However, it must be (even though undoubtedly extremely slight) introducing some distortion.

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