pane of glass to block hum?

While a single pane of glass in front of your gear could 'block" some level of hum, it will likely just redistribute it and glass is more of a sound transmitter than sound isolator. Thicker glass will reduce sound transmission, a double pane of glass with an air gap in between will do better, but then you're talking about building a wall or cabinet around the Fraim to isolate hum from within. In that case you get into air circulation issues and potential overheating of gear. Presumably you're considering glass because you want to still see your gear or use a remote control? If not, sound absorbing materials like foam or fiber would be better choices to deaden the ambient hum.

I would try to work on the underlying cause of the problem, which is dirty mains being fed into your PSUs.

Aleg is right, anything that keeps the sound in (120Hz isn't significantly directional) will also keep the heat in, and that isn't good for the electronics!

I've had 3 different Naim amps in my current room. Two of them hummed audibly from anywhere in the room; one (my 200DR) is virtually silent. I don't know if that's just luck or sample variation, or maybe it's quieter by design? 

As for the glass idea, I'd be very surprised if it made a worthwhile difference unless it was part of a built-in cupboard. 

ChrisSU posted:

I've had 3 different Naim amps in my current room. Two of them hummed audibly from anywhere in the room; one (my 200DR) is virtually silent. I don't know if that's just luck or sample variation, or maybe it's quieter by design? 

As for the glass idea, I'd be very surprised if it made a worthwhile difference unless it was part of a built-in cupboard. 

It's just random chance.

And the cupboard will need ventilation, which'll let the 120Hz (or 100Hz) hum out back out as well as the hot air.

Huge, I suspect you are right on both counts. 

Maybe a fridge is the answer - insulated, sealed, and temperature controlled. 

ChrisSU posted:

Huge, I suspect you are right on both counts. 

Maybe a fridge is the answer - insulated, sealed, and temperature controlled. 

And it even hums worse than the transformers.   D'oh!   

Huge posted:

ChrisSU posted:

Huge, I suspect you are right on both counts. 

Maybe a fridge is the answer - insulated, sealed, and temperature controlled. 

And it even hums worse than the transformers.   D'oh!   

My fridge is probably about as loud as the hum from my Superuniti, so I imagine 8 Naim transformers in the same room might be considerably worse. I would do some trials, but taking the beer out of the fridge to make space is a no-no.

You don't have a separate fridge for your beer?

Huge posted:

You don't have a separate fridge for your beer?

Actually, I made that bit up! Being English, I drink my beer at room temperature.

Thanks for all the feedback, yes I think the glass idea would not necessarily be successful. I have tried to see what appliance may be causing it but not with any luck. I know that my neighbour has some solar panels and I reckon the inverters he uses may be the things at fault, but who knows.

I did once get a response from Phil Harris on a similar subject and he did mention that naim once did come up with a solution but it was not economically viable. Thing is that with some of the systems that have had significant investment, what ever they came up with may be something that we would buy. 

Good job Naim never made active speakers.   Would never sell because of too much hum emanating forthwith and trembling.

Can you install a dedicated mains supply. It may reduce the hum, especially if it's due to other things interfering. 

most certainly have a dedicated 40 amp mains supply, mind blowing upgrade but hum still persists.

I see you live in Sydney.  If you were in the UK then I would suggesting that you could maybe persuade your electricity company to look at moving you to a different phase of the 3 phase supply that goes past most houses, because it's quite likely that there will be an available phase with less DC offset. But I don't know what the electricity distribution situation is like in Australia.....

best

David

ChrisSU posted:

I've had 3 different Naim amps in my current room. Two of them hummed audibly from anywhere in the room; one (my 200DR) is virtually silent. I don't know if that's just luck or sample variation, or maybe it's quieter by design? 

As for the glass idea, I'd be very surprised if it made a worthwhile difference unless it was part of a built-in cupboard. 

my 200DR is silent as well. 

Maybe its time for a league table of the amps that do and dont (with their ages in case that is relevant). Then conclusions could be drawn as to whether certain amps are more prone than others, which in turn might possibly be relatable to the particular transformer design.

Although primarily focused on Naim amps, no harm in identifying others, so my contribution:

• Musical Fidelity P270 circa 1990 does hum sometimes.
• Bryston 4Bsst circa 2004 never hums

My Supernait 2 doesn't hum at all. The CDX2 does hum a bit but it doesn't disturb me (the hum is totally inaudible when playing music).

I think the amp  or power supply model is not the factor that determines wether it hums or not, it is purely luck of the draw with the toroidal transformer inside the box. One that hums does not mean that it sounds worse, and it probably does not hum at the factory, but in our homes, it is effected by all types of mains distortion. Each one is different, think they may be hand wound or something that makes them slightly different from one another in a mechanical sort of way. Lay mans terms I know, but this is a mysterious topic.

Naim need to come up with a device that addresses our mains as they have tried many quiet transformers that just don't make music. They are silent all right, but they don't sound any good. This just sounds like a problem that naim have the know how to sort, and it's sort of an embarrassing problem with kit that is so expensive. I have an armageddon that is totally silent by the way, there is almost no way of knowing that its on. Makes you wonder why this sort of consistency can't be repeated and naim are really big on consistency. We may seem unreasonable not accepting this hum issue, we obviously don't understand the manufacturing difficulties but we still by the product. 

Naim are always looking for new markets and customers but now its time to reward the faithful!

Mario posted:

 

Naim are always looking for new markets and customers but now its time to reward the faithful!

The faithful having already forked over their hard earned cash are less interesting than the new customers.

Iconoclast posted:

Mario posted:

 

Naim are always looking for new markets and customers but now its time to reward the faithful!

The faithful having already forked over their hard earned cash are less interesting than the new customers.

The faithful know that there is nothing better than active naim and will buy more if it makes what they already have even better! 

Upgrading slowly, step by step is how naim has become so successful and this type of mains product would be another upgrade as they would only release such a thing if it improved sound quality.

Any comments from moderators or technical support?

Mario.

Hi Mario,
Sorry to read that you too suffer from those transformer hum blues.  Two thoughts for you:

1) The hum is a low frequency sound, so will radiate around a glass panel.  High frequency sounds can be blocked by a barrier in the "line of sight" but a low frequency sound will go around it.  The glass panel idea will have little, if any, effect on your hum.

2) HH suggested a separate mains feed, which often helps.  If that is not enough, look up this thread:
"Suffering from those transformer hum blues?"  I started it in May 2015, and the solution has worked superbly for us.

Best regards, FT