If you like the amp, try fixing the problem (identifying and eliminating the root cause if an item or items of domestic equipment, and if none then trying a DC blocker, after first checking your mains is within voltage spec). If the amp doesn’t wow you, then indeed why bother?
As nothing has changed around here I can’t see what could be causing the buzz other than the amp itself. From what I’ve heard DC blockers can have a negative effect on dynamics, don’t want to spend money for something that might end up in a drawer. For now I’ll just put up with it as is, if I find another amp that sounds better at a reasonable price then I’ll probably cut my losses and move on. Montreal AudioFest a month from now will be a good chance to check out options.
You can order a dc blocker from many online sites, like Analog Seduction for example, or MCRU . They offer 14 days try and return policy.
If your problem is solved with it and the dynamics untouched, it’s worth trying it.
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Not sure where you’ve heard that, from what I’ve read thats not the general opinion.
In my experience a DC offset filter gives a slight improvment in SQ
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I presume you mean you/your household have not changed anything, However it is possible that something in your home could have deteriorated though still working, causing a DC offset. Or something may have changed external to your home. Or the mains voltage may be excessive at times of hum, previously more stable.
I Googled ‘‘ifi silentpower dc blocker sound quality’’ and this came up…
Higher frequency grain and sibilance were reduced. However, I also found some mild loss of tactile dynamic expression, and the presentation seemed a mite slower and less rhythmic.
Could be that one of my neighbors installed something that is causing this or that my fridge compressor is getting old but I have no way of knowing for sure.
The Ifi is blocking via a filter mechanism. There are two main ways of attacking this: filtering and regen; versus balanced isolating transformers. The latter being large and ideally should be rated at equal or greater than the circuit they are on. They themselves often inherit the hum so located far away is best, such as in the garage. Hospitals must use these so the majority on the market aren’t “audiophile” grade but cost less and work just as well.
With things like the Ifi, (I have one but don’t need it. It was for experimental purposes) or any other small in-line mains device, it’s likely to be benign on units with low stable current drawns like sources and preamps. But I’d avoid them on power amps or integrateds as they are very sensitive to increased resistance.
FYI
Continuing the discussion from Transformer hum:
I’ve read varied results from trying these, so best to try and see - every case may be different.
The changes can have occurred in the area of his house. I live near a very big school. It’s closed on holidays. The first hour when it opens again, I have generally some humming from my 555 dr. Just to say that outside changes can impact the inside mains.
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Yeah my electrician was adamant that although I had decided to not install a balanced isolating transformer on the CU feeding the main hifi, I might reconsider that given how much crap will come from the other 10 houses on the street. He wasn’t thinking of humming though. Just general noise rubbish.
I had actually ordered one and then cancelled it. The unit cost was okay. The 2% leakage on a 30 KVA just seems like too expensive and irresponsible before I know there’s even a problem.
I did not have the iFi device in mind, my experience is with the traditional large series capacitor & diode bypass type.
Left the poll open longer than planned but okay. Would be great to get 200 votes in but either way, I’ll chop the data a bit in a week.
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I have 4 Naim based systems of which 3 are actively used
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Malaysia 240V region Server room. Statement amps hum. So they had to be shifted to the server room with speaker cables poking through the wall to the main listening room
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Malaysia 240V region 552 + 300DR in the master bedroom. Amp hums. Defeated using a DC blocker
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Australia 240V region 252 + 250 in the games room. Amp hums. Defeated using a DC blocker
Conclusion, Naim amp hums.
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I’ve had humming XPS 2 and 555DR.
Also had humming Crimson 640 and Audiolab 8000p, so not just Naim.
I tried two different dc blockers to no avail.
I have a plug in voltage measuring device which was generally in the high 240s, occasionally over 250.
Recently the measured voltage has dropped to 227 - 235 and things are now blissfully silent. I’m hoping it will stay that way 
Over voltage is, in my experience, far more often a culprit than DC offset. If only because DC offset is actually quite rare whereas overvoltage is very common.
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In your experience, normally how many percent over-voltage over the rated input voltage of an amp will transformer buzz / hum start to occur?
In my experience, I am currently on around 249V, and I get humming, but when the electricity was temporarily dropped to about 240, it was nearly gone. It tends to be higher for people that are closer to their substations, as they have to allow for Voltage Drop to cover the furthest property
Anyone tried or have power stations/re generators like those PS Audio and others make?
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