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Post by MartinT on Jan 8, 2018 21:26:14 GMT
It could be. I know nothing about farming but it does seem to be a regular daily occurrence.
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Post by ChrisB on Jan 8, 2018 21:29:13 GMT
That's what I thought. It's the wrong time of year for a grain dryer.
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Post by MikeMusic on Jan 8, 2018 21:30:43 GMT
My Harvesters went mad this morning then stopped.
They often flash quite a lot thing around 6-7am
Rarely notice them any other time.
Tony found my DC was out and put a blocker in the AM filter
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Post by pinkie on Jan 9, 2018 9:24:53 GMT
The P10's transformer never hummed. However, the power amp and preamp's did (a little). As I remember saying at the time, DC appears to affect the P10's performance through to the components it's powering. This is confirmed by their preferring clean regenerated power over raw mains now. Have I got this right? In your experience, without first filtering the DC supplied to the PS Audio P10 mains regenerator, that device supplies power to audio devices connected to it which has a DC element which causes the transformers in those connected devices to hum. I don't believe the manufacturer subscribes to that view. Did you ever manage to measure the DC on your mains at the time? Have you managed to measure it now? Are you just assuming it was there and isn't now? If not, what reliably measured DC component was there before (As Mr MCRU pointed out, cabling , including changing the transformers, would not change DC on the mains. Whatever sort of transformer you had before would output AC with no DC element. The DC component comes from other devices connected to the same power line. Mr MCRU is incorrect in stating those are in your own home, for the fairly blindingly obvious reason that it is possible to measure DC on your mains (my mains) with absolutely nothing connected and running in the house) |
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Post by MartinT on Jan 9, 2018 11:22:20 GMT
Richard, I've stated my findings endlessly only for you to change them into something I didn't say. DC on the mains affects the P10's performance. Ask David Brook about it (he sells DC blockers and the P10). It certainly affected mine. The P10 does not output DC, that is not what is happening. I'm fairly sure I stated at the time that my DC on mains was over 2V, measured by the sparky who installed the radial.
Do you understand power transmission? It's not my specialisation, but in re-cabling a village and replacing sub-transformers, the network impedance changes quite a lot. Asymmetrical loading on that network will change depending on where it is located. Not to mention new earth bonding to neutral over that network. The overall effect is change! I do agree that it's not my house creating the DC over mains.
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Post by pinkie on Jan 9, 2018 13:11:59 GMT
I'm fairly sure I stated at the time that my DC on mains was over 2V, measured by the sparky who installed the radial. My mistake I thought this was your last comment on the subject, May 5, 2017 10:48:33 GMT 1 MartinT said: I'll get my 'scope on it sometime, I may just have the resolution to see the offset and scale it between AC and DC views. But maybe I missed something - for God's sake don't go inviting DQ back to chastise me that I should "search the archive". I'm just trying to understand properly, cos I'm a bit muddled. I am still puzzled by your (mildly) humming transformers on the Pass audio devices plugged into the P10. Am I right they hummed for reasons which were nothing to do with DC on their supply, since the P10 provides DC-free power, but whatever was wrong with the power supplied by the P10 which made these transformers hum, was fixed by filtering the DC from the supply to the P10 itself? Perhaps Mr Brock could tell us - are PS Audio aware of this defect in their product? |
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Post by Deleted on Jan 9, 2018 13:20:46 GMT
To DC or not to DC this is the question? Tis nobler in the mind to suffer The slings and arrows of Pinkie's outrageous meanderings, Or to take Arms against an overwhelming sea of DC offset, And by opposing it, end the foul influx of DC: to die, to sleep No more; and by a sleep, to say we end the sly retrograde of DC. Take heed my noble appreciators of the art, dark days lay ahead  |
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Post by MartinT on Jan 9, 2018 14:40:16 GMT
May 5, 2017 10:48:33 GMT 1 MartinT said: . . . I am still puzzled by your (mildly) humming transformers on the Pass audio devices plugged into the P10. That was some time after I had the radial installed by the sparky and after the village rework! I'll try once more to explain: the P10 is affected by DC on the input, pretty much like any hi-fi component. After all, it's a sodding great amplifier of sorts (waveform repairer, strictly speaking). It isn't defective, none of my components are! SEPARATELY from this... If I put my ear to the Pass power supply or listen to the Belles up close, with the P10 off (raw mains) I can hear slight hum. It's not surprising, the waveform looks like a sawtooth with around 2.7% THD (which varies). If I power up the P10, the hum reduces. It's not surprising, the waveform is sine and the THD is 0.1%. This translates to better sound quality, which I can hear. |
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Post by DaveC on Jan 9, 2018 15:05:00 GMT
the P10 is affected by DC on the input, pretty much like any hi-fi component. But it isn't any other HiFi component. It's a mains conditioner, it should not need "pre-conditioned" mains? I would send it back for checking, there might be other issues. Any other HiFi component design properly, should be fine whatever the circumstances, like Pass is now after I worked with them ? Dave |
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Post by MartinT on Jan 9, 2018 15:13:43 GMT
Don't be silly, there's nothing wrong with it. It's as if people don't read what I wrote, but what they want to think I wrote.
I have little DC on my mains now. I've already said I've taken the blocker out of circuit as it no longer serves any purpose.
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Post by docfoster on Jan 14, 2018 13:04:59 GMT
I don’t know the P10.
And I’m no technical expert like you guys, but if the P10 runs off a toroid, and if that toroid runs directly off the mains (ie without any DC blocking), and if that toroid is of a type that is vulnerable to some humming due to DC, then presumably the toroid in the P10 might hum if DC is present, regardless of the quality of the AC the P10 ultimately puts out to the hifi.
A lot of “ifs” in there. As I say, I don’t know the P10, but the above scenario is what seems to happen with my balanced mains unit. Its toroid hums to a significantly lesser degree than have other toroids I’ve used (e.g. in amps), but it’s not zero. Hence my use of a DC blocker whose insertion between wall socket and balanced mains unit has eliminated what few humming incidents there were. (As would be expected, the toroids that feed off the balanced mains unit never hum, with or without the DC blocker in place in between wall socket and the balanced mains unit.)
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Post by nrg on Jan 16, 2018 14:34:00 GMT
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Post by MartinT on Jan 16, 2018 14:38:45 GMT
Yep, read it before and it explains the effect very well.
The MCRU Ultimate DC blocker that I'm selling is made by Nick.
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Post by sq225917 on Jan 17, 2018 0:12:50 GMT
Let's assume that the P10 isn't perfect.
Let's assume that it cannot correct for an unlimited amount of noise on the mains and that it cannot eliminate an unlimited amount of DC on the input.
These two facts have to be true, it'll be specified to reduce noise to a specific level over a set frequency range, and output an Ac waveform with noise within pre-set bounds.
So if he has a crap load of DC on the input, enough to saturate the transformer core then it's possible that it could affect the output..
I don't know how much DC he has, or how skewed and clipped his AC input in because of this but I'd have to come down on the side of 'possible'
Frankly the attack on Martin over on HFS about the sale and use of his DC blocker with/without his P10 just shows how quickly Mr Dunn is prepared to ignore logic and years of electrical engineering theory when it suits his need to slight a poster.
Thankfully Nick knows his arse from his elbow and has written up his DC blocker function in detail.
The truth and drivers for Richard's interaction on this thread is obvious.
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Post by MartinT on Jan 17, 2018 7:09:27 GMT
Let's assume that the P10 isn't perfect. Let's assume that it cannot correct for an unlimited amount of noise on the mains and that it cannot eliminate an unlimited amount of DC on the input. Good assumptions and true for pretty much any piece of equipment. I do laugh when I read the oft-used phrase "a well designed power supply should be immune . . . blah, blah, blah". If that were really true then no amount of work on mains supply and/or bigger PSUs would make the slightest bit of difference to sound quality. Clearly (to my ears and others whose hearing I trust), it is not true. PSRR means that no circuit is entirely immune to power supply issues - it's a ratio, after all! |
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Post by DaveC on Jan 17, 2018 7:49:56 GMT
I broadly agree with SQ (unlimited), however I have spoken at length with PS Audio in Colorado and I'm waiting for the transformer designer that I use to return next week. The outcome of my research is likely to please almost everyone, except those who make poorly designed power supplies and that's no one here. I might even buy a PS Audio P5 !
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Post by Deleted on Jan 17, 2018 9:27:19 GMT
What most audio electronic manufacturers assume is that the UK voltage is 230Vac and therefore make their transformers in that realm. Not realizing that it can go as high as 255Vac which will cause a core to saturate and destabilize.
If the cores were rated at 250Vac this would not be the case imho
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Post by Deleted on Jan 17, 2018 9:52:34 GMT
What everyone needs is a Naim XPS2 or 555, Naim make the best power supply's you can buy, don't you know  |
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Post by MartinT on Jan 17, 2018 9:58:47 GMT
The outcome of my research What research is that, Dave? |
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Post by DaveC on Jan 17, 2018 10:23:28 GMT
What research is that, Dave? Talking to the engineers at PS Audio and also to my transformer manufacturers designer. I think I indicated that ? You wrote about me recently "an engineer who rates himself above all others (Cawley)" which is largely true, but even I have to talk to designers to fully understand where they are coming from and how they design individual products. But Martin, let's not make this personal. |
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