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Post by MartinT on Sept 13, 2020 17:46:57 GMT
Martin, I'd be interested in your subjective listening thoughts with the filter plugs in and out of the system if you haven't tried that already after your testing. I have, Jules, and it's pretty much as I've said already: All unplugged: there is a subtle loss of stage depth, low level ambience, note decay, delicacy and general low level detail. Emphasis here on subtle, this is NOT a big difference. All plugged in: as I have been enjoying for a long time, all the above things at the level I've been used to. Only Sercal/Kemp/Protek/Harmonix plugged in: still can't be sure but it's at least as good as the above and I think I detect some more things I hadn't noticed before. Please don't think this is night-and-day stuff, it really isn't. It's highly likely that my regenerators are hiding the worst effects of mains-borne EMI. What I hear is only the residual effect. It surprises me that there is any left at all, but then I am reminded of PSRR. There is always some that gets through. |
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Post by BilliumB on Sept 13, 2020 18:16:55 GMT
Might not the big issue be what’s actually going on on the Earth/Ground line, especially if this is connected to the 0v line in your kit (assuming it’s not double insulated). .... Remember, this is primarily for safety. Yes, of course the Earth line is there for safety (and vital), however it would be very interesting to investigate the noise waveform and amplitude on this line - it must impact the sound from your system. It would also be interesting to see what impact the grounding boxes have on this noise level (possibly having a localised impact where connected). I'm sure it’s time to get hold of a sensitive 'scope and have a look! Also, have you checked the impact of removing your grounding boxes on the measured noise levels with the Chinese meter? Cheers. Bill |
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Post by MartinT on Sept 13, 2020 19:58:36 GMT
I'd love an up to date sensitive 'scope. Unfortunately, I only have an old 20MHz dual trace 'scope.
As for the grounding boxes, they're designed to sink local noise from the component's ground plane. I cannot see how they would influence mains-borne noise or are in any way connected?
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Post by BilliumB on Sept 13, 2020 21:16:36 GMT
Wouldn’t they be connected within the equipment to the power supply earth?
Cheers. Bill
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Post by BilliumB on Sept 13, 2020 21:19:58 GMT
Have you had a look with your ‘scope?
Cheers. Bill
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Post by ChrisB on Sept 13, 2020 22:19:17 GMT
Unplug them all.
Take the one that measures the worst and plug it in.
What does that do to the sound?
If it's worse, then bin it.
If its better or the same, then hang onto it. For now.
Rinse and repeat with them all.
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Post by MartinT on Sept 14, 2020 5:27:11 GMT
Wouldn’t they be connected within the equipment to the power supply earth? No. You don't connect grounding boxes to supply earth. EDIT: Oh, I see what you mean now. They are designed to drain noise from the ground plane so are only indirectly connected to supply earth. |
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Post by MartinT on Sept 14, 2020 6:47:19 GMT
Unplug them all. Take the one that measures the worst and plug it in. What does that do to the sound? If it's worse, then bin it. If its better or the same, then hang onto it. For now. When I have time, which I don't at the moment. I want to enjoy music and not do too much faffing around. Perhaps over the Christmas break when I 'escape'! I'm not going to bin any of them. They're useful for the future if I ever get my hands on a better measuring device. |
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Post by BilliumB on Sept 14, 2020 16:38:33 GMT
Wouldn’t they be connected within the equipment to the power supply earth? No. You don't connect grounding boxes to supply earth. EDIT: Oh, I see what you mean now. They are designed to drain noise from the ground plane so are only indirectly connected to supply earth. If you do get the chance it would be interesting to see the impact on the meter measurement from removing the grounding box that you feel has provided the biggest improvement. By the way, do you attach the meter to the circuit to take measurements, or do you simply 'wave' it near the circuit to measure radiated noise? Cheers. Bill |
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Post by MartinT on Sept 14, 2020 16:46:42 GMT
It plugs into the mains, takes power and the measurement signal directly.
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Post by MartinT on Sept 14, 2020 17:27:55 GMT
I received my two LED bulbs to replace the CFL bulbs in my music room. The LEDs are dead quiet with no change in resting noise at a very low 15mV. Turning on the P10 and power amp raised it to a still very low 19mV. So that is 'system idle' noise level, I'm not going to get better than that.
Turning on just one CFL raises it by +20mV, one light dimmer by +200mV so you can see how sensitive things are.
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Post by MartinT on Sept 16, 2020 13:09:07 GMT
Found a video of my meter in use!
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Post by MikeMusic on Sept 16, 2020 13:16:24 GMT
That bloody noise !
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Post by MartinT on Sept 16, 2020 13:37:05 GMT
Exactly - designed to irritate the more mains noise there is.
A perfect design!
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Post by MartinT on Sept 16, 2020 13:51:08 GMT
Exactly - designed to irritate the more mains noise there is. A perfect design! Hint: you don't leave it running while listening to music. |
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Post by MikeMusic on Sept 16, 2020 15:17:59 GMT
I'd be looking for the mute button as I would lose the will after a few minutes
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Post by MartinT on Sept 16, 2020 16:42:24 GMT
It's a test tool! The audio output is a good indicator of high noise when you can't look at the display. It barely makes any noise at the resting levels in my music room.
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Post by MikeMusic on Sept 16, 2020 16:51:31 GMT
It's a test tool! The audio output is a good indicator of high noise when you can't look at the display. It barely makes any noise at the resting levels in my music room. Sensitive little me might be able to cope with that  |
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Post by MartinT on Sept 16, 2020 17:47:12 GMT
It might be screaming in your house!
I shall bring it over if that ever becomes possible.
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Post by MikeMusic on Sept 16, 2020 20:00:41 GMT
Tony plugged in his wonder kit to show a laptop screen of harmonic noise I think it was
It moved around as he changed parameters.
There was all sorts of rubbish there.
Maybe my mains would break your little item ....
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