Appreciate the advise GagetMan, yes you’re right, but I’ve worked with electricity all my life, and my Fluke meter has been checked (not calibrated as such) against a recently calibrated meter about 4 months ago.
However I’m not at all concerned with my own voltage.
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Thanks for the nudge, I will certainly look at it again. Humming now is not audible when music is playing, but I also wonder if a humming device causes more heat than a non humming device.
Hi Mike, sorry, but I wasn’t trying to give you advice, as I know you know all this, but reading back my previous answer could be ready a different way. Anyway, I know you wont take offence but just wanted to apologise for not wording it better.
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Absolutely no offence taken GadgetMan, it didn’t even cross my mind.
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This is what my Myenergi Zappi records. API monitoring by Home Assistant. I have frequency also.
Phil
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Did the 156 cure all transformer hum for you and did you try another product limiting DC prior to 156? I have a DC filter which is not enough in eliminating the hum for some reason. I have a 500PS, 552PS and 555PSDR and they all still hum but the 552PS hum louder than the others and the 555PSDR is the most quiet. I had plans ordering the 156 but the retailer here said they have long delivery right now due to the high interest.
Which power cord do you use into the 156?
PS: My voltage meter shows 229V and I have a DC blocker prior to the block so all boxes have it on them.
Depends on the root cause. DC offset is one of several causes. Over voltage is more common. Defectivr windings also exist but are very rare.
You need to root cause it before prescribing a cure.
I suspect the occurrence of overvoltage varies on a country-by-country or at least region-by-region basis, so in so e places may be more common than DC on the mains, while in other places less common. Based on times when I have had cause to check voltage in the British Isles, I don’t recall ever finding the voltage to exceed the statutory limits,
How much over voltage is required? Thing is all my boxes ever owned have reacted differently to this even with identical setup.
My voltage seems to move only few Volts around 230 so must be DC that slips through. I believe the threshold for a DC blocker is higher than what is required to set a naim transformer into buzz mode. Maybe the Puritan 156 manage this better than my Supra. Will order it.
I couldn’t justify the price of a 156 as I need something like 23 sockets for transformers, although the noisier ones are probably nearer 15
Having graphed out the mains voltage can you give us feedback on transformer hum at these times relative to graph readings?
Once again balanced supply, say goodbye to naim hum, plus no sound quality loss, just lovely blackness quite
To be honest in my home there is no correlation with transformer hum. Only the 500 PS hums. Before with a 252/300 (all DX) the 555DX hummed. It went completely quiet! I guess the hum is more to do with the spatial coupling between the coils or the interaction as they draw from the mains.
I don’t hear the minor hum when I’m listening nor do I try to hear it. It don’t think it impacts on the music.
What the meter tells me is that the voltage varies throughout the day. It’s high when grid demand is low and lower when’s demand is high. It is within the grid limits.
Phil
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I can confirm that when I reported an average Voltage of 255V to the Electricity Board, they came, and during investigation, dropped it for a day to 240V. That pretty much stopped my humming. Unfortunately the final fix they put in place leaves me with a value in the late 240’s, and humming is back but not to original levels. But of course this is only one possible reason for humming.
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Excuse my ignorance but is a balanced supply and what do you need to achieve this?
A balanced supply is where you have 115volts going down both the live, and natural.
This works just like a balanced xlr cable in that they each cancel out each other as far as any interface, noise, etc.
It’s not that expensive to do, around £500, but it depends on what load you are running.
It’s not a new thing, hospitals, recording studios, measuring equipment, etc. They all use tend to use balanced supply.
It’s a proven way, its a simple way, and it far cheaper than fancy mains blocks.
I have a separate mains supply to my hifi, from a separate consumer unit, the balanced transformer goes between the hifi consumer unit and the main tails into the house aftet meter.
Cheers dunc
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Interesting solution, thanks.
If you’re interested, look at Airlink. They produce a good range of balanced and other power supplies, including some suitable for HiFi, and they are very helpful.
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Bear in mind that this is a transformer, and therefore can also hum, so best sighted back at your dedicated HiFi Consumer unit if possible
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Mine is a very large airlink hifi model, and pleased to say it doesn’t hum
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