Sorry - Noisy Transformers Again - Advice Welcome - Update that could be controversial

Yes - it is an often discussed topic, though sadly with very few obvious ‘solutions’. I have ordered an Isotek Evo3 Isoplug to see if that makes any difference. The issue will probably disappear just as the Isoplug arrives - that’s what I am hoping anyway.

Best of luck anyway. I cured my hum, which was a dc offset issue, with a dc filter. Again, it was the wife’s dryer and light dimmers. I actually removed all dimmers in the house anyway.

I never worry about them, they come and go and generally disappear as quick as they came.

Sorry with Naim amps, no short cut it requires a dedicated mains spur.

He’s got one.
Infact it shows that a dedicated mains isn’t the cure in all cases.

Maybe Neil meant this great work by GadgetMan?


Weird, I have one standing close by as well and no issues. Was it plugged into the same power block?

Have you switched off your other mains circuits in order to eliminate other home devices as the possible cause?

Yes and it has no effect. As I said in an earlier reply nothing has changed in my house for 18 months. Kitchen appliances were top of my list to investigate - but no change when I took the kitchen ‘off line’.

Thanks - missed it when it hit the Forum - smug in my ‘quiet’ environment! Very interesting. It has actually become a little better over the course of today - so I’m hoping my prediction holds true, it goes as the Isoplug hits the doormat.

1 Like

I use an ‘Isol-8 PowerLine Axis’ DC-Blocker to great effect.


I had it next to the stand. Once I figured out it was the Orbi I played around with the power supply and then eventually tried waving the Orbi around near and further away, bingo that was the source. The buzz was loudest when it was in held on front of the volume knob. Curiously, the buzz almost disappeared when I touched the volume knob (but only the volume knob, touching the amp case had no effect on the noise).

I hadn’t appreciated how much effect a wireless device could have. It’s now about 6’ away and no buzz for me.

That’s some good sleuthing.

Mine is just under a meter away and no issues. But a while back it was standing tight next to my Star and nothing.

Read somewhere that some transformers are affected more than others so perhaps that?

I did get some really audible hum from my Star’s transformer by either plugging it on the same power bank as the TV or having a hair dryer on ontheven same power line upstairs.

So guess what - just entered my main living room and my gear is as quiet as I have ever heard it! Isoplug not even shipped yet.

So it must have been external - I.e supply grid - factors at play.

Can close this post.


Adding this to my original retitled post so that I don’t have to repeat things.

So the Isotek Evo3 Isoplug arrived. The transformer noise had returned, though not as continuously as before. So I unplugged the Xerxes from the bottom of my three double power sockets into which all my gear is plugged (happens to be the first socket the dedicated supply sees) and inserted the Isoplug. Things were quiet at that moment - but I popped in and out of the room over the next few hours and it was clear that when there were noisy periods they were still there but definitely tamed - and bearable. Had that not been the case the Isoplug would have been out - only £110.00 wasted.

I thought I better now check the effect on the sound quality - expecting the worst and therefore a difficult decision. What followed was a three hour listening session to make sure that I could believe my ears! Yep - sound quality was obviously improved from the very first track to the last. It is like the bandwidth of the system has been widened. Same glorious sound as I have been used to but with more top and bottom information and definition.

This probably falls into the shelf height, stacking order, plug order and cable dressing theatre of improvements - but to my ears it is definitely there. Might just be my setup - but for the cost it’s worth a try.

No brickbats please - just passing on my experience.

1 Like

As a final confirmation, may be worth putting it back to how you started after say a week of getting used to it

1 Like

I haven’t read the full detail of all posts here, but if it hasn’t been said already intermittent hum from the transformers is almost certainly DC on the mains, which could be coming from something within, or external to the home. The only solution is to find and fix the source(s) if within the home, or block the DC: two options for latter, a specialised DC blocker, or an isolating transformer. The latter is likely to be the more expensive.

More here:

1 Like

Yep, if it’s coming from the street or wider network, that dedicated mains won’t do anything.

‘Isolate PowerLine Axis’ dc-blocker completely eliminated my intermittent hum/buzz issues.


So - to confirm - you plugged in the IsoTek EVO3 ISOPLUG to the first of 6 UK wall sockets that are wired up in series on one dedicated hifi radial.

And you moved all your hifi equipment plugs to the other (later in the chain) 5 sockets.

And this made an audible improvement to SQ, as well as significantly cutting (but not eliminating) transformer buzz on your Naim system?

i.e. the IsoTek EVO3 ISOPLUG cleaned up the electrical feed - presumably by DC on the line?

And - speculating - the improvement in SQ was probably due to lowering the electro-magnetic noise floor?