Question Amp Hum

655321

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Hello Everyone,

Please forgive the user name, I'm in the naughty box for using an ad blocker (rectified now). I can't change my name at the moment.

Avatar image is by Zdzisław Beksiński in case you're wondering.

Anyway, on to my question: With new amps with hum, from the amp itself, is it normal to hear that hum reduce as the amp “beds in”?

I ask because I have just purchased an amp that was really noisy when I first plugged it in, but has got quieter as I’ve left it on over the last 3 days.

Thanks in advance for anyone taking the time to write a post!
 
I would check that it is the Amp is causing the issue (hum). Have you isolated the amp and still hear the hum? If that is the case I would suggest there is an issue with the amp and it should be returned for repair or if new, exchange.

If the hum appears once a source is plugged in, it will likely be an earthing issue or positioning of the source is causing interference. In that case try cleaning the earth connection or consider isolating the source further away from the amp. Turntables can be especially finicky things....

Personally, I don’t buy into the “bed itself in” nonsense, often put out by hifi sales people, it’s simply not a credible argument. In 40 years of buying Hifi, I have never, ever had an amp on “start up” make any unwanted noise, if it did, it would be going back.
 
Hello Johnny and daddy999,

Thank you both for replying!
I apologise for not responding sooner, work has been quite hectic.

The hum on the amp has reduced quite a lot. After posting I purchased a entry level "conditioner" (Tacima) and I've kept the amp on standby when not in use.

I have to say the amp's sound quality has got noticeably better after two weeks of ownership.

Currently, if I put my head about two feet from the amp in a quiet room, I'll hear the hum.
I've also noticed it gets a bit louder with my TV & sound bar on.
Finally, I think that the amp is susceptible to DC current on the AC mains. I have so many wall warts, I think some of them are leaking DC.

I'm currently looking at some of the products from ISOL-8, they filter DC on the mains.

Once again, thanks :)

Kind regards,

655321 or Patrick.
 
Nope shouldn’t be any hum and if you’re in the UK shouldn’t need power conditioning either but many will say otherwise on that.
 
Hello Mary,

Thanks for posting.

Are you saying that DC voltage leaked onto AC mains does not happen in the UK and does not cause hum?
I'm not trying to be confontational, I'm trying to understand if what I've read about the subject is snake oil or not.

What about the reduction in hum when useing a basic conditioner? I forgot to mention that that my TV & sound bar are now on a different plug socket at the other end of the room.

Again, thanks for posting.
Any help in sorting out truth from snake oil is very welcome!

Best regards,

Patrick.
 
No problem :)

I’m saying that in my experience that a bare amp with volume at any vaguely sensible level does not produce hum (not like back to the future lol). Either at the speakers or of itself. If hum then appears as sources or subs etc are connected there’s a fault not something that an expensive piece of nonsense should be fixing. I know there are a lot of power products available with a lot of ‘reasons’ for their existence I just haven’t seen one (in the UK) that I don’t think is snake oil. For mains equipment at least. Power supplies for DC are another matter.
 
what amp are you running?
 
Hello Johnny and daddy999,

Thank you both for replying!
I apologise for not responding sooner, work has been quite hectic.

The hum on the amp has reduced quite a lot. After posting I purchased a entry level "conditioner" (Tacima) and I've kept the amp on standby when not in use.

I have to say the amp's sound quality has got noticeably better after two weeks of ownership.

Currently, if I put my head about two feet from the amp in a quiet room, I'll hear the hum.
I've also noticed it gets a bit louder with my TV & sound bar on.
Finally, I think that the amp is susceptible to DC current on the AC mains. I have so many wall warts, I think some of them are leaking DC.

I'm currently looking at some of the products from ISOL-8, they filter DC on the mains.

Once again, thanks :)

Kind regards,

655321 or Patrick.

Hi Patrick,
sounds like transformer hum from your description. Is the unit easy to get into? If you disconnect the mains you could open it up and check if the transformer is tightly mounted to the chassis. It is usually held by a nut or four. Cheers.
 
Every single amp that Ive owned has a hum. Most of them you cannot hear the hum from the MLP, but it's audible when you rest your ear on top of the amp above the vents. It's more noticeable when its completely silent in rest of the house and the only other thing you can hear is the clock ticking or the alarm control panel.
 
@password1 My Lyngdorf doesn't hum if you want an amp that doesn't.
 
Hello Folks,

Thanks again for posting, it's really appreciated.

I checked the nut on the toroidal transformers and it was a little loose by half a turn.
Tightened it and things are much better. :thumbsup:

Thank you all again for taking the time to help me out.

Patrick
 
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Just to provide some experience on this, I had some transformer hum and a mains conditioner did not make a significant difference. A DC blocker similar to the above helped but primarily during times of high electricity usage (when hum was typically much louder). Be aware that it is said that either of these products can affect sound quality negatively (although I found this fairly insignificant).

Matt
 
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