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Post by stellabagpuss on Oct 27, 2024 14:39:23 GMT
So had a bit more time, to experiment further. l moved the Tacima back next to the in coming mains again, back in the house,and as MartinT reported it does reduce the interference, although somebody has something on in the neighbourhood as it was jumping between 4.8 to 5.6.
lnterestingly l brought the Tacima block back to the cabin, where the reading went lower to 3.2
This leaves me with two thoughts,reducing as close to power comes into the house works, but gets less effective as you move away, and in my case that's about 25 metres away. Bottom line, l need more filters, in terms of sound, l've never been happier.
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Post by julesd68 on Oct 27, 2024 15:02:49 GMT
What does a reading of 5.7 actually mean?
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Post by MartinT on Oct 27, 2024 15:16:06 GMT
What does a reading of 5.7 actually mean? It's a reading relative to the baseline measurement, i.e. 5.7% of the unfiltered noise. |
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Post by stellabagpuss on Oct 27, 2024 15:18:08 GMT
What does a reading of 5.7 actually mean? 100 is a unfiltered mains, so 100%. That's your baseline. So 5.7 is 5.7% which is a reduction, but not that good if you look at MartinT readings when he's tested the Kemp,that's 1.3% ish. My Puritan PSM 156 is 0.8%, l think it measures in microvolts,not near the unit atm, perhaps MartinT can confirm. |
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Post by MikeMusic on Oct 27, 2024 15:18:52 GMT
I am an aerial
My LHY arrived late yesterday
Testing today
First try, double socket in kitchen where mains comes in to the house
Kemp off, LHY on.
Noisy.
Turn up and pick up radio with adverts
Kemp back on.
Silence
Different socket
Vertex plug off
LHY on
Same again except this time an Indian radio station
Vertex on and silence
Leave filters plugged in
Into the music room and the same effect
Does this mean I need a filter in every double socket
Work in progress...
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Post by stellabagpuss on Oct 27, 2024 15:28:53 GMT
I am an aerial My LHY arrived late yesterday Testing today First try, double socket in kitchen where mains comes in to the house Kemp off, LHY on. Noisy. Turn up and pick up radio with adverts Kemp back on. Silence Different socket Vertex plug off LHY on Same again except this time an Indian radio station Vertex on and silence Leave filters plugged in Into the music room and the same effect Does this mean I need a filter in every double socket Work in progress... Could be a combo of things Mike, your Mains Wiring, Overhead Cables and even the crap lead LHY provided, so l plan to change the lead tomorrow and apply some sheilding. l guess it's more of the case that the choosen frequency of the LHY is in the Medium Wave band, and because it has a speaker to reproduced the mains noise, chances are it's not far off the bandwidth of a MW transmission,hence why you can hear the radio audio. Wait until tonight, when the Skywaves hit.. you'll get all sorts of random stuff,in nutshell it's the same as puttinga,aerial on your radio Don't let it bother you to much, the filters are doing the job. |
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Post by mattspl on Oct 27, 2024 15:50:32 GMT
I am an aerial My LHY arrived late yesterday Testing today First try, double socket in kitchen where mains comes in to the house Kemp off, LHY on. Noisy. Turn up and pick up radio with adverts Kemp back on. Silence Different socket Vertex plug off LHY on Same again except this time an Indian radio station Vertex on and silence Leave filters plugged in Into the music room and the same effect Does this mean I need a filter in every double socket Work in progress... It could be that you need to filter the mains near the source and again near your system, particularly because the kitchen and music room are likely on different circuits. I’m using a Kemp at the consumer unit and the right socket in the living room and the Fidelity Audio in the left living room socket where the majority of the Hifi is plugged in. Each filter contributed to better sound. |
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Post by MikeMusic on Oct 27, 2024 18:30:59 GMT
I am an aerial My LHY arrived late yesterday Testing today First try, double socket in kitchen where mains comes in to the house Kemp off, LHY on. Noisy. Turn up and pick up radio with adverts Kemp back on. Silence Different socket Vertex plug off LHY on Same again except this time an Indian radio station Vertex on and silence Leave filters plugged in Into the music room and the same effect Does this mean I need a filter in every double socket Work in progress... Could be a combo of things Mike, your Mains Wiring, Overhead Cables and even the crap lead LHY provided, so l plan to change the lead tomorrow and apply some sheilding. l guess it's more of the case that the choosen frequency of the LHY is in the Medium Wave band, and because it has a speaker to reproduced the mains noise, chances are it's not far off the bandwidth of a MW transmission,hence why you can hear the radio audio. Wait until tonight, when the Skywaves hit.. you'll get all sorts of random stuff,in nutshell it's the same as puttinga,aerial on your radio Don't let it bother you to much, the filters are doing the job. Tried a Russ Andrews cable with a Figure 8 end. Same noise Currently I put the LHY in any double socket and have noise, no matter where the other filters are. The filters are doing their job. Not sure why I still have so much noise on the LHY |
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Post by MikeMusic on Oct 27, 2024 18:32:53 GMT
I am an aerial My LHY arrived late yesterday Testing today First try, double socket in kitchen where mains comes in to the house Kemp off, LHY on. Noisy. Turn up and pick up radio with adverts Kemp back on. Silence Different socket Vertex plug off LHY on Same again except this time an Indian radio station Vertex on and silence Leave filters plugged in Into the music room and the same effect Does this mean I need a filter in every double socket Work in progress... It could be that you need to filter the mains near the source and again near your system, particularly because the kitchen and music room are likely on different circuits. I’m using a Kemp at the consumer unit and the right socket in the living room and the Fidelity Audio in the left living room socket where the majority of the Hifi is plugged in. Each filter contributed to better sound. Filters have proved themselves with sound improvements in the system Puzzled with the noise still found in any double socket that doesn't have a filter |
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Post by stellabagpuss on Oct 27, 2024 18:43:29 GMT
It could be that you need to filter the mains near the source and again near your system, particularly because the kitchen and music room are likely on different circuits. I’m using a Kemp at the consumer unit and the right socket in the living room and the Fidelity Audio in the left living room socket where the majority of the Hifi is plugged in. Each filter contributed to better sound. Filters have proved themselves with sound improvements in the system Puzzled with the noise still found in any double socket that doesn't have a filter l would say Matt is on the money, possibly that socket is run off another spur. On the positive side, your set up is singing nicely. |
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Post by MikeMusic on Oct 27, 2024 22:01:07 GMT
Filters have proved themselves with sound improvements in the system Puzzled with the noise still found in any double socket that doesn't have a filter l would say Matt is on the money, possibly that socket is run off another spur. On the positive side, your set up is singing nicely. More work to do now I have the meter Two circuits tried so far, kitchen, 3 sockets and music room, 2 sockets Was hoping to find answers to the weirdness I have with electrics but seem to have added more questions |
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Post by stellabagpuss on Oct 27, 2024 22:29:41 GMT
Plug-in Mains Noise Filters ReviewI decided to purchase a mains noise sniffer to see for myself how effective (or not) my collection of plug-in mains noise filters are in reducing mains-borne noise pollution. Cleaning up mains power quality is one of my key tenets to good sound quality and I’ve probably bored most members rigid with it!  The test unit is a Chinese LHY Audio ‘Line EMI Meter’ costing around £75 with import duty and VAT. It measures noise in mV as well as line voltage. It also has a bar meter at the top and plays the noise as sound, getting louder the worse the noise. It’s a fascinating instrument and I learned a lot more about what creates noise in my household than I had ever known before. The maker suggests these noise ranges versus ‘goodness’: ＜50mV
| Excellent
| ＜100mV
| Very good
| ＜800mV
| Good
| ＜1,000mV
| Average
| ＞1,500mV
| Poor
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The main barn ‘resting’ noise, with all filters plugged in, is around 20mV. The music room is a little noisier at 26mV. However, see later on for just how much this can vary. Filter Test Results
The results rather shocked me, and I did a couple more rounds of each plug-in to verify my findings, using different sockets for the meter and test subject with all the other filters unplugged. | Model | Noise Reduction (dB) | Russ Andrews The Silencer
| +4.9 | | Tacima SC5723 | +4.3 | | Isotek Isoplug | +3.8 | | Isotek Neoplug | +3.5 | ifi AC Purifier
| +3.2 | | PS Audio Noise Harvester | +2.6 | | VertexAQ Jaya | +0.9 | | Harmonix Enacom | 0 | | Isotek Protek | 0 | | Kemp SNS | -2.0 | | Sercal NoNoise SE | -2.2 |
Yes, you’ve read that right. Most of the plug-in filters ADD noise! The two stars of the show are the Kemp SNS and, top of the pile, the Sercal NoNoise SE, which did their advertised job of reducing mains-borne noise. Possibly most disappointing are the ifi AC Purifier and PS Audio Noise Harvester, which are active devices and which I expected to perform a lot better. Other Sources of NoiseThis is where I got a real shock. The ‘resting’ noise of the main barn, if you remember, is around 20mV. While I was looking at the meter, Ruth turned on the TV. The noise immediately went up by +40mV and it started wailing. Then I turned on the dimmed LED lights above our dining table and the noise shot up by +200mV with the meter screaming. Wow! I also found the CFL lights in the music room, an upright lamp and table-top lamp, each added about 12mV of noise. Luckily, my LED uplighters contribute nothing. So I’ll be looking to replace both CFL bulbs with non-dimmed LEDs. Conclusions- The meter is a wonderful new way for me to understand what’s going on with mains noise and correlate it with performance.
- I cannot explain why so many of the filters appear to add noise. However, that’s what I’ve measured so they’re coming out of circuit.
- I have left only the Sercal and Kemp in circuit in the music room, with the Protek plugged in for protection as it contributes no noise.
Test Limitations- The meter only tests for noise across Live and Neutral. No considerations of noise on the Earth (Ground) side are taken into account.
- Some of the filters interact with each other and are sensitive to how far away they are from each other and from the meter. I used the best readings in each case and tested them alone.
- The meter measures noise in the band 10kHz to 10MHz. Noise is known to exist further up the spectrum so take these measurements as guidance only.
- The ears don't necessarily hear what the meter measures. I have some more experimentation to do.
Just wondering if this meter is better at giving a,fuller picture as,it covers 10khz to 10mhz which is has over 20 times bigger coverage then the latest LHY meter. |
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Post by mattspl on Oct 27, 2024 22:54:00 GMT
Has anybody any thoughts on using an oscilloscope to measure the mains? Is it possible or the wrong tool for the job?
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Post by MartinT on Oct 28, 2024 3:51:32 GMT
More work to do now I have the meter Two circuits tried so far, kitchen, 3 sockets and music room, 2 sockets Was hoping to find answers to the weirdness I have with electrics but seem to have added more questions Did you actually follow the process I gave, removing all filters and setting the meter to 100 at the incoming noise? I don't see that you have reported any noise reduction figures. |
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Post by MikeMusic on Oct 28, 2024 9:14:33 GMT
More work to do now I have the meter Two circuits tried so far, kitchen, 3 sockets and music room, 2 sockets Was hoping to find answers to the weirdness I have with electrics but seem to have added more questions Did you actually follow the process I gave, removing all filters and setting the meter to 100 at the incoming noise? I don't see that you have reported any noise reduction figures. Using it to see and hear what happens Amazing the amount of noise and then drop to silent All off next to try Do you think I need to turn off the AM conditioner, as I think that is comprised of filters That means all off on the system so to be avoided if possible |
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Post by stellabagpuss on Oct 28, 2024 11:00:37 GMT
Did you actually follow the process I gave, removing all filters and setting the meter to 100 at the incoming noise? I don't see that you have reported any noise reduction figures. Using it to see and hear what happens Amazing the amount of noise and then drop to silent All off next to try Do you think I need to turn off the AM conditioner, as I think that is comprised of filters That means all off on the system so to be avoided if possible You turn off all conditioning,plug the LHY meter in to the closest socket to your consumer board,it should be noisy, set it as close to 100 as you can ,it's normal for it to jump below and above. You then have a base line,if you plug turn one of the filters on ,and plug the LHY in,the LHY should display a figure, of course turning on more filters should lower readings, but start with one and a take a reading,then add another filter etc .. Then report back to us on TAS with the readings, the lower the better. |
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Post by palace on Oct 28, 2024 12:17:30 GMT
When I shielded my power & phono leads with copper foil, removing multiples ferrites from phono & coax/digital on advice from HD Music & Test & others, I found this white paper "A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing" originally relating to Audio, the information below was taken/borrowed from another forum & may be of use to the mathematically gifted on the forum using LHY meters. "This paper may be the best place to start, although there are several others on interference. Don't let the title fool you, this started as an audio system paper, then a lot of Ham information was add:" "A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing" "by Jim Brown K9YC Audio Systems Group, Inc. audiosystemsgroup.comThe basis of this tutorial is a combination of my engineering education, 55 years in ham radio, my work as vice-chair of the AES Standards Committee working group on EMC, and extensive research on RFI in the pro audio world where I’ve made my living." www.audiosystemsgroup.com/RFI-Ham.pdfAddendum : Subsequent to copper foil shielding the leads to reduce/stop common mode interference I have clipped on ferrites. To cope with differential mode interference, I have taken several bare 13 amp plugs in spare sockets, I have strapped Y2 capacitors across positive to the earth pin & negative to the earth pin, since if they fail they go open circuit (safe) capacitors for common mode fail closed circuit (iffy in my book) thankfully ferrites fulfill this common mode function, I read a online manual for a Tisbury preamp "Interference: Make sure your turntable’s ground lead is connected to the Domino’s ground post. Use high quality shielded interconnects. Attach a ferrite core to the ground lead near Domino’s ground post" I therefore have 4 clip on & a 25mm ring ferrite wrapped around with the single ground/earth wire from the turntable/tone arm to the Croft phono stage grounding/earthing point, in my case the reduction in noise RFI/EMI 50hz was very marked. |
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Post by stellabagpuss on Oct 28, 2024 13:50:46 GMT
I will download that, most of my ideas have come from my years of radio and experience with antennas. For myself the subjects are closely related.
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Post by MikeMusic on Oct 28, 2024 15:44:07 GMT
Using it to see and hear what happens Amazing the amount of noise and then drop to silent All off next to try Do you think I need to turn off the AM conditioner, as I think that is comprised of filters That means all off on the system so to be avoided if possible You turn off all conditioning,plug the LHY meter in to the closest socket to your consumer board,it should be noisy, set it as close to 100 as you can ,it's normal for it to jump below and above. You then have a base line,if you plug turn one of the filters on ,and plug the LHY in,the LHY should display a figure, of course turning on more filters should lower readings, but start with one and a take a reading,then add another filter etc .. Then report back to us on TAS with the readings, the lower the better. Got that Turning off the AM conditioner means everything goes off Be a while for it all to come back again, hopefully without incident |
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Post by stellabagpuss on Nov 17, 2024 13:34:44 GMT
LHY meter update, l've just got my hands on Airlink ASF3000 balanced transformer.
Direct in the wall, with my DIY filters and Tacima on the ring mains, it reads 0.15 that's not too shabby.
I then plugged the Putitan PSM156 into the Airlink.... 0.4 now that is low,down from 0.6, will be interesting to see what adding the Kemp SNS before Airlink will do when it arrives
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