Question A humming receiver and what to do about it...

[gmatkin]

Does anyone have any advice please?

A week ago, I purchased a hifi receiver and on connecting it up, found that it suffered from an annoying hum in the left-hand channel, while the the right hand channel was much quieter.

I tried every remedy for hum that I could think of and also tried disconnecting all the inputs - but still the hum wouldn't go.

I connected up all my usual inputs to my previous amplifier, a Denon PMA100M. Left and right channels were both dead quiet, connected or disconnected.

I returned the product to the supplier, and today received another example of the same model of receiver. It too has a left-hand channel hum, both when connected and otherwise. I can hear it clearly at 10ft away.

This evening, I switched over the speaker cables. This made the right hand speaker hum, so I think I can rule out interference in the speaker cable (though that always seemed unlikely or impossible).

Could it be that the product has a design fault that could cause the problem? Could the two receivers have the same manufacturing fault? Do I have to return it and buy a different receiver? Are there any other tests I can try that would reveal anything useful?

Is there some earthing trick I could try? I notice that the mains cable plug has no earth, as the earth pin is plastic.

If there's a way of getting this right, I'd be very grateful - if I send this thing back, an alternative of the same wattage from the same store would be significantly more expensive!

Thanks, Gavin Atkin

 

[nopiano]

What make and model is it, please? And what devices are you connecting as a source? (I’m keeping fingers crossed it isn’t a Rega turntable).

What’s it standing on or near, and are any other products, e.g. TV, phone charger, lamp, etc connected nearby or sharing the same gang?

What advice did the supplier offer?

Welcome to the forum!

 

[Cork]

A hum is often a ground loop.

 

[Fandango Andy]

Does anyone have any advice please?

A week ago, I purchased a hifi receiver and on connecting it up, found that it suffered from an annoying hum in the left-hand channel, while the the right hand channel was much quieter.

I tried every remedy for hum that I could think of and also tried disconnecting all the inputs - but still the hum wouldn't go.

I connected up all my usual inputs to my previous amplifier, a Denon PMA100M. Left and right channels were both dead quiet, connected or disconnected.

I returned the product to the supplier, and today received another example of the same model of receiver. It too has a left-hand channel hum, both when connected and otherwise. I can hear it clearly at 10ft away.

This evening, I switched over the speaker cables. This made the right hand speaker hum, so I think I can rule out interference in the speaker cable (though that always seemed unlikely or impossible).

Could it be that the product has a design fault that could cause the problem? Could the two receivers have the same manufacturing fault? Do I have to return it and buy a different receiver? Are there any other tests I can try that would reveal anything useful?

Is there some earthing trick I could try? I notice that the mains cable plug has no earth, as the earth pin is plastic.

If there's a way of getting this right, I'd be very grateful - if I send this thing back, an alternative of the same wattage from the same store would be significantly more expensive!

Thanks, Gavin Atkin

Almost certainly an earthing issue. Have you tried isolating it? do you have any sources plugged in? Does it do it on all source inputs? does the amp have a phono stage, and if so do you have anything connected to the phono RCA's and or the earth? Is the transformer internal or external? Do you have balanced connections?

 

[gmatkin]

What make and model is it, please? And what devices are you connecting as a source? (I’m keeping fingers crossed it isn’t a Rega turntable).

What’s it standing on or near, and are any other products, e.g. TV, phone charger, lamp, etc connected nearby or sharing the same gang?

What advice did the supplier offer?

Welcome to the forum!

I'm not keen to mention the model, as I don't want to be unfair to the supplying businesses; the issue could conceivably be due to something external to the receiver. I will say that it's a 100W/side stereo receiver from a well known name, and that experience has shown that I need this level of power for my Dynaudio speakers.

The turntable is an updated Rega Planar I first bought in the 80s.

It's in a hi-fi furniture unit, in which there is:
- an eight socket mains extension installed to eliminate hum loops, two unused USB sockets and two USB wall warts
- a recent hifi CD player
- a DVD player
- a cheapie MM phono preamp and its dedicated PSU
- two optical to phono adapters, one from the TV, one from the CD player (they eliminated a hum I got when I was using the previous amp)

There's a Samung TV on the wall above.

Thinking about all this, I'm unclear why any problems with these things would affect only one channel of the new amp but not the old one.

Gavin

 

[gmatkin]

Almost certainly an earthing issue. Have you tried isolating it? do you have any sources plugged in? Does it do it on all source inputs? does the amp have a phono stage, and if so do you have anything connected to the phono RCA's and or the earth? Is the transformer internal or external? Do you have balanced connections?

I tried unplugging all the inputs, and the left channel still hummed. Is there anything further I could try to isolate it further somehow?

 

[gmatkin]

Almost certainly an earthing issue. Have you tried isolating it? do you have any sources plugged in? Does it do it on all source inputs? does the amp have a phono stage, and if so do you have anything connected to the phono RCA's and or the earth? Is the transformer internal or external? Do you have balanced connections?

All except the Bluetooth input - but I guess that's suppressed when the Bloot isn't paired with anything.

 

[Fandango Andy]

I tried unplugging all the inputs, and the left channel still hummed. Is there anything further I could try to isolate it further somehow?

The only other thing you haven't mentioned, but probably tried first is move the amp out of the unit and try it away from all other components.

And finally, again you have probably already tried it, google: "humming noise from X receiver" to see if anyone else is having them same problem.

 

[gmatkin]

The only other thing you haven't mentioned, but probably tried first is move the amp out of the unit and try it away from all other components.

And finally, again you have probably already tried it, google: "humming noise from X receiver" to see if anyone else is having them same problem.

Googling around suggests hum is a common hifi problem (which I knew) but not that it's associated with this model, particularly.

 

[gmatkin]

I unplugged all the inputs, took the receiver out of the hifi furniture unit and plugged it into a plain 6-way power extension with no USB PSU sockets.

The left channel is still humming, though /perhaps/ a bit less. The right channel is nearly silent, as before. Presumably this is best I can hope for.

I'm pretty disappointed. All I wanted was a beefy receiver with a remote control, which should be easier than this! I don't fancy being reduced to buying one or more spendy receivers at random in the hope of success...

Gavin

 

[Fandango Andy]

Googling around suggests hum is a common hifi problem (which I knew) but not that it's associated with this model, particularly.

It happens, but I wouldn't call it common.

One last thing. Did you buy from a shop? Take it in and get them to hook it up and listen.

 

[twinkletoes]

I unplugged all the inputs, took the receiver out of the hifi furniture unit and plugged it into a plain 6-way power extension with no USB PSU sockets.

The left channel is still humming, though perhaps a bit less. The right channel is nearly silent, as before.

I'm pretty disappointed. All I wanted was a beefy receiver with a remote control, which should be easier than this! I don't fancy being reduced to buying one or more spendy receivers at random in the hope of success...

Gavin

Well there are a number things to try before spending money.

Hums can be an inherent problem Naim I could hear the transformer from across the room, the actual transformer not the background hum from speakers and would get louder at certain times of the day.

If this was a ground problem i'd actually half expect your Rega to have problems. In all honesty

Is this something you actually hear at your listening seat or do you have your ear an inch away from the speakers?

Anyhow, do you have a really retractable extension lead that would allow you try different sockets around the house. ie maybe in the hallway if possible. If not its going to be a bit of lifting involved and it will need to be done to make sure speakers don't have problem.

other simple things

Turn the TV off and unplug

remove phono stage

trun off the fridge for a short time or anything with a compressor

unplug everything around the room reading lights (especially dimmable ones), lava, lamps that sort of thing

are any of your speaker cable/cables touching an aerial/sky lead/HDMI. try to re-sort the order a little.

Are any cables touching the chassis on the amp

are any of you cables coiled up rather than ribboned and tied especially long lengths

If you have a ground wire is it installed correctly

lastly can you try your amp and speaker completely outside of your house, family member or friend house

No need to spend money till you have exhausted every possible avenue.


Failing all of that take it to a dealer for a service or a replacement if under warranty

 

[Al ears]

It happens, but I wouldn't call it common.

One last thing. Did you buy from a shop? Take it in and get them to hook it up and listen.

Indeed, if this is new or even ex demo I would be returning it. There is no excuse for excess hum in modern equipment especially when its one channel more than the other.

 

[podknocker]

Humming, coil whine, fan noise and capacitor whistling are totally unacceptable in modern electronics.

 

[Gray]

There's a simple, conclusive test:

Take the receiver and your speakers to another house - preferably in another street.
(If they've got speakers, it will save you taking yours).

With nothing connected except the mains and speakers and with the volume control at minimum, power up the receiver.
If you've got hum from the speaker (or anywhere else) that you can hear from 10 foot away....YOU DONT WANT THAT RECEIVER.

It's as simple as that 👍
Doesn't matter if you can switch input and kill the hum.
Doesn't matter whether it's a design fault.
Doesn't matter if it's a component fault.

Lose it.
You could conceivably try a third example of the same model - I wouldn't.

EDIT: Before doing the above, listen on headphones -if hum is present on those it will save you connecting (risking) speakers to test.

 

[Juzzie Wuzzie]

Is your Denon PMA100M power cord truly earthed? Does the new amp allow you to try a different (earthed) power cord?

Irrespective, I'd return it.

 

[JDL]

I think the best thing you can do is get rid of it. Your old system didn't hum. Two of this model, whatever it is, does hum. That's enough evidence to suggest that your best option is to send it back, while you still can and avoid this model.

 

[gmatkin]

Well there are a number things to try before spending money.

Hums can be an inherent problem Naim I could hear the transformer from across the room, the actual transformer not the background hum from speakers and would get louder at certain times of the day.

If this was a ground problem i'd actually half expect your Rega to have problems. In all honesty

Is this something you actually hear at your listening seat or do you have your ear an inch away from the speakers?

Anyhow, do you have a really retractable extension lead that would allow you try different sockets around the house. ie maybe in the hallway if possible. If not its going to be a bit of lifting involved and it will need to be done to make sure speakers don't have problem.

other simple things

Turn the TV off and unplug Done

There's a simple, conclusive test:

Take the receiver and your speakers to another house - preferably in another street.
(If they've got speakers, it will save you taking yours).

With nothing connected except the mains and speakers and with the volume control at minimum, power up the receiver.
If you've got hum from the speaker (or anywhere else) that you can hear from 10 foot away....YOU DONT WANT THAT RECEIVER.

It's as simple as that 👍
Doesn't matter if you can switch input and kill the hum.
Doesn't matter whether it's a design fault.
Doesn't matter if it's a component fault.

Lose it.
You could conceivably try a third example of the same model - I wouldn't.

EDIT: Before doing the above, listen on headphones -if hum is present on those it will save you connecting (risking) speakers to test.

remove phono stage

trun off the fridge for a short time or anything with a compressor

unplug everything around the room reading lights (especially dimmable ones), lava, lamps that sort of thing Largely done

are any of your speaker cable/cables touching an aerial/sky lead/HDMI. try to re-sort the order a little.

Are any cables touching the chassis on the amp

are any of you cables coiled up rather than ribboned and tied especially long lengths

If you have a ground wire is it installed correctly

lastly can you try your amp and speaker completely outside of your house, family member or friend house

No need to spend money till you have exhausted every possible avenue.


Failing all of that take it to a dealer for a service or a replacement if under warranty

 

[gmatkin]

I thought we were on to something, thanks to twinkletoes.

I unplugged the HDMI cable from the DVD player to the telly at the TV end, and the one-sided hum stopped.

So I wrote a note here to explain and say thanks.

But now the hum is back.

Hey ho...

 

[nopiano]

I'm not keen to mention the model, as I don't want to be unfair to the supplying businesses; the issue could conceivably be due to something external to the receiver. I will say that it's a 100W/side stereo receiver from a well known name, and that experience has shown that I need this level of power for my Dynaudio speakers.

The turntable is an updated Rega Planar I first bought in the 80s.

It's in a hi-fi furniture unit, in which there is:
- an eight socket mains extension installed to eliminate hum loops, two unused USB sockets and two USB wall warts
- a recent hifi CD player
- a DVD player
- a cheapie MM phono preamp and its dedicated PSU
- two optical to phono adapters, one from the TV, one from the CD player (they eliminated a hum I got when I was using the previous amp)

There's a Samung TV on the wall above.

Thinking about all this, I'm unclear why any problems with these things would affect only one channel of the new amp but not the old one.

Gavin

Thanks, Gavin. You’ll have seen from subsequent replies that many of these things can have a bearing on noise. Various power supplies and other devices can often be a source of noise unless placed carefully. However, I acknowledge that the one-channel issue is unusual, unless it’s narrowed down to something like a turntable input.

You may have seen from searching that Rega are more than averagely prone to hum, as they use an unusual earthing arrangement without a separate earth lead.
However, you’ve tried many other tests and I’d be giving up on it too.

There’s no need to be coy about the make and model, because you may save someone else the same grief. You’re not doing other than reporting your experience, but ultimately it’s your choice.

Maybe it’s cheap because they’re end of line or defective in a way that not everyone notices. It’s anyone’s guess.

Good luck.

 

[podknocker]

I bought a new NAD T585 for £200 YEARS ago and it was faulty and hummed. It wasn't earthed and this was noted in red ink on the repair invoice. Maybe I'm an uber cynic, but I often think companies / vendors know they are faulty and sell them at a discount price, in the hope these things won't go wrong and will last the warranty period.

 

[twinkletoes]

I thought we were on to something, thanks to twinkletoes.

I unplugged the HDMI cable from the DVD player to the telly at the TV end, and the one-sided hum stopped.

So I wrote a note here to explain and say thanks.

But now the hum is back.

Hey ho...

Looks like you have an RF induced noise problem

When you say it's now back what made it come back did you keep the cables removed? TV unplugged? DVD player unplugged or did you reintroduce them?

Or was coincidence that something in the house went off as you were experimenting? if so, what? boiler, fridge, cooker.


Sounds like you're getting close to source of them problem though. keep at it you will find it

Edit
By chance are you using a cheep 6 gang extension for your devices? ie is your amp plugged straight into the wall?

 

[gmatkin]

Looks like you have an RF induced noise problem

When you say it's now back what made it come back did you keep the cables removed? TV unplugged? DVD player unplugged or did you reintroduce them?

Or was coincidence that something in the house went off as you were experimenting? if so, what? boiler, fridge, cooker.


Sounds like you're getting close to source of them problem though. keep at it you will find it

Edit
By chance are you using a cheep 6 gang extension for your devices? ie is your amp plugged straight into the wall?

I did nothing. I just went next door into the kitchen for lunch.

I am. What would you recommend please?

Thanks, Gavin

 

[Covenanter]

Hum nearly always arises from a "ground loop". This is where the components in a system don't share a common earth. This can happen even when they seem to have a common earth just because of a poor connection somewhere. For example, two wall sockets in a house will share the same earth wiring but if one has a loose connection there will some resistance and then you can get hum. Similarly a multi-way mains connector can suffer from this.

I suggest that you plug all your kit into one wall socket if you don't already and make sure that you are using a good quality mains connector. Also you can look in every plug and make sure that the earth wire is really well screwed down. If you have any doubts about how to do this get an electrician to do it for you.

 

[gmatkin]

Thanks, Gavin. You’ll have seen from subsequent replies that many of these things can have a bearing on noise. Various power supplies and other devices can often be a source of noise unless placed carefully. However, I acknowledge that the one-channel issue is unusual, unless it’s narrowed down to something like a turntable input.

You may have seen from searching that Rega are more than averagely prone to hum, as they use an unusual earthing arrangement without a separate earth lead.
However, you’ve tried many other tests and I’d be giving up on it too.

There’s no need to be coy about the make and model, because you may save someone else the same grief. You’re not doing other than reporting your experience, but ultimately it’s your choice.

Maybe it’s cheap because they’re end of line or defective in a way that not everyone notices. It’s anyone’s guess.

Good luck.

My Rega turntable is so old, it actually has an earth lead ;-)

I needed to be convinced that the problem is not of my making before fessing up; but I will now say that it's a Yamaha RS202D.

Gavin