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Post by Deleted on Oct 30, 2016 11:03:04 GMT
With relation to the French mains, my adopted step father owned several properties in the Angoulême including a hotel. On average the hotel was blowing around 200+ light bulbs a year!!!
I fitted a 230V regulator a few years ago, now maybe 20 bulbs a year lol
French mains electricity supply is truly shocking not just for over voltage but the sheer amount of common mode and harmonics that are present.
Standardizing the voltage to 230Vac i the UK was a paper exercise not a physical lowering of the voltages imho.
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Post by pre65 on Oct 30, 2016 11:45:46 GMT
I fitted a 230V regulator a few years ago Can you elaborate on that part please ?
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Post by MartinT on Oct 31, 2016 8:41:07 GMT
Electro-mechanical Variac can do that.
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Post by pinkie on Oct 31, 2016 9:17:49 GMT
A variac (one of Martins autotransformers) can of course drop the voltage by a fixed amount. Regulators usually combine a monitoring circuit and relays to switch to autotransformer positions on under or over voltage and keep within a tighter range from a wider one. That said - the issue always appears to be excess voltage rather than "brown outs" as supply companies prefer to keep voltages towards the top of the range to minimise current in the supply network.
It is interesting to note this is yet another Brexit item. EU voltage requirements were standardised around 230V. However, rather than change actual voltages, which would have been costly, the range bands were changed (the UK was the odd one out again and would have needed to lower its voltage, or the whole of the rest of the EU raise theirs)
So in the UK the voltage is 240v +6% or -10% giving a range of 216 to 254.4 as the acceptable supply from the utility companies. In the EU the range is 220 +10% -6% giving 206.8 to 242V. So to be compatible with all permitted EU voltages equipment should be designed to operate with a supply voltage from 206.8 to 254.4. (Note these are sometimes quoted as UK 230 +10% -6% and the other EU 230 +6% - 10% which give very nearly the same numbers)
I haven't measured the voltage in France yet - I need to fit a radiator once it stops being so glorious outside, and that will be an opportunity to measure. But ideally, well designed equipment will work within a wide range of voltages.
You can get a voltage regulator fitted to the main consumer unit as a cost saving device - since lower voltage means lower current and power, and power is the unit of charge. Generally you split the board so that circuits supplying heat are not reduced in voltage (or they would take longer to cook, dry etc).
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Post by Deleted on Oct 31, 2016 9:56:46 GMT
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Post by BilliumB on Oct 31, 2016 19:30:01 GMT
I've been pondering about moving to a balanced supply some time in the future - also have high supply voltage (sometimes over 250v) and get buzzing issues at times on my Conrad Johnson CA200 amp - it's the 230v European version but do wonder whether its US origin means that it's better suited to a 60 Hz supply. I've fitted a Longdog Audio dc blocker and that has helped, but not solved the problem so do suspect the high voltage might be an issue.
I'm thinking of getting a balanced transformer wound (and of course fitted with all the relevant trips) designed for 250v input and 115v 0v 115v output - any thoughts?
From reading Philip Newell I see that recording studios often use a combination of an isolation transformer then feeding into a balanced transformer prior to the kit - does anyone have any experience of the benefits of such an approach?
Cheers. Bill
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Post by pinkie on Nov 1, 2016 9:21:26 GMT
Bill
I would have to leave Conrad Johnson to speak for themselves, but one would hope that such a manufacturer would use an appropriate transformer in its European specified equipment. It is possible to have a transformer operate at both frequencies but it will have more headroom at 60Hz.
A balanced (or any other transformer) with a 250v input supplied with 230v will produce less voltage than intended. You will step down 250 to 230 if the supply is 250, but if the supply drops below 250 you still step down a fixed proportion and risk aggravating a low voltage situation. If your supply voltage is consistently reliably too high by 20v its a solution. If your supply voltage fluctuates within permitted tolerances, and drops to the lower range, you could create a problem even in well designed equipment intended to operate in the 206 to 253 range. (If I have my sums right, if your input voltage is 230v then your output supply voltage will be 212v. If the input voltage drops to a permitted 222v then even equipment properly designed for the full range could be in trouble)
Regarding Phillip Newell and balanced power, he is an advocate of wiring studios that way, sometimes. Balanced powers origins were for sensitive medical equipment. A lot of the noise problems are radiated from cables in addition to being conducted on ground cables. So balanced power was authorised in the USA for installation in medical facilities, subject to controls. Having balanced powers in the walls could make a noticeable difference. Having it in the last bit coming out of a balanced supply - MUCH less so (don't forget the feed to the balanced supply is another unbalanced mains lead in the room). Connecting the "clean" balanced ground to a "dirty" supply ground (earth) also "sub-optimises" the solution. P N's installations almost certainly include a completely separate ground.
He makes some interesting comments
In 25.5 he says " in 1996 there was an amendment to the US National Electrical Code which allowed audio-video and similar installations to be run from balanced power systems as long as certain specific conditions were met**. ... in other countries ... it may be possible to use a free standing unit feeding the plugboards to which audio equipment is connected. This is not something which should be undertaken without expert advise (sic) because the use of isolation transformers might (sic) defeat the operation of differential circuit breakers (RCD's) , which are essential safety features in many installations. Further protection will likely be necessary on the isolated side of the wiring"
** The 2002 code includes "The system's use is restricted to areas under close supervision by qualified personnel."
He also explains why balanced mains may often be the only practical way to achieve the necessary level of noise reduction in a studio environment (which of course affirms there are other ways to achieve the same goal).
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Post by BilliumB on Nov 1, 2016 20:27:52 GMT
The other area I plan to do some work on sometime in the distant future is on grounding. Clearly all the safety issues need to be understood and complied with - and many will be on PME systems that do not allow much latitude. However, I'm on a TT system with a local earth spike and so there is more that I can do. When the electrician was last here doing an inspection for me he measured the earth loop impedance Ze via the earth spike as 15.07 Ohms and from the socket used for my audio kit as 15.62 Ohms - he was happy with these figures, but agreed that some form of improved earthing arrangement (much deeper spike, buried earth mesh etc) plus a lower impedance connection to earth (obviously with relevant connections at the main board) could improve matters considerably (along with a dedicated consumer unit and radial power feed). How much impact these would have on musical enjoyment I'll have to see! One issue I'd like to better understand is the type of 'wire' that would provide the lowest impedance earth path to audio noise signals (what frequency would these be?) - my kit is probably at least 20m from the main electrical board and earth spike. From my days of dealing with audio signals in electrically noisy fast jets, I doubt that standard twin and earth cable is going to be optimal! If you're interested in grounding issues, Philip Giddings has written some good stuff - including on balanced power - hopefully this link will get you to some of it www.sounddesigndevices.com/documents/Power%20Grounding%20and%20Noise%20by%20Philip%20Giddings.pdf Cheers. Bill
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Post by MartinT on Nov 1, 2016 21:00:56 GMT
My electrician intrigued me with his statement that most house electrical earths (tied to the incoming neutral line) offer a better (lower impedance) 'earth' than local ground spikes or buried grids. He showed me some measurements and was quite persuasive. I have therefore gone with it and given up the idea of a separate local earth.
P.S. my Ze earth measurement is 0.24 ohms.
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Post by Sovereign on Nov 1, 2016 21:23:26 GMT
My electrician intrigued me with his statement that most house electrical earths (tied to the incoming neutral line) offer a better (lower impedance) 'earth' than local ground spikes or buried grids. He showed me some measurements and was quite persuasive. I have therefore gone with it and given up the idea of a separate local earth. P.S. my Ze earth measurement is 0.24 ohms. That's very interesting Martin. Are you able to Publish what you were shown? The earth of my Hifi is still connected to the incoming tails. It wouldn't take much for me to disconnect and link to a dedicated earth and see if I can hear a difference. Not that that will happen any time soon as I have too much on at the moment.
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Post by BilliumB on Nov 1, 2016 22:21:50 GMT
Hi Martin - sounds like you have got a PME earth, I think that sort of reading is quite normal in that situation. If you have got PME rather than TT setup then you need to be very careful in adding earth spikes as some fault conditions can be very dangerous (if I remember correctly a neutral fault in your area could lead to fault currents from adjacent properties all flowing into the earth spike that you might have added!) It would normally say somewhere near your meter whether you have a PME setup.
I do wonder though how noisy the PME earth connection might be as, I think, you'll be linked to everybody else locally.
Not sure whether some sort of 'technical earth' (see Giddings papers) might be worth looking into.
Cheers. Bill
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Post by MartinT on Nov 1, 2016 23:09:24 GMT
Thanks, Bill. I'll leave well alone for now.
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Post by pinkie on Nov 2, 2016 6:34:01 GMT
Bill That's one of the better papers I've seen on this subject and I hadn't seen it before. From just wanting to think carefully about an aggressive (false) statement made by a manufacturer about safety considerations with these devices I have learned more about the subject from an expert friend than I ever intended. I still understand it less well than I would like.
Key points are
The disadvantages paragraph. Couldn't put it better. Balanced power is NOT certain death for anyone using it, but it's supply and installation require a proper open understanding of its affect on important existing safety features, including legal and insurance implications
Earth and ground are not the same. Noise does not "bleed off" to earth. The connection to true earth is primarily for lightening protection
Equipment chassis grounding and signal ground should be separate paths.
Balanced power is a solution for fixing poor grounding - to deal with ground line noise (and in permanent specialist installation in a whole room or building radiated noise). Balanced system connections, proper equipment shielding and ground connections are more effective solutions.
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Post by MartinT on Nov 2, 2016 6:47:44 GMT
That's very interesting Martin. Are you able to Publish what you were shown? Unfortunately, James, I just looked over his shoulder as he talked me through it and showed me completed inspection charts from other premises. He said it was very rare that a local ground spike/grid betters the supplied earth. Bill - yes, it's a PME with earthing at continuous points along the supply line and a combined earth/neutral feed into the house. Thereafter, earth is kept separate from neutral as per the regulations.
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Post by Deleted on Nov 2, 2016 9:22:28 GMT
The quality of the earth inside your dwelling can have a very marked effect on your sound imho
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Post by Sovereign on Nov 2, 2016 10:53:13 GMT
The quality of the earth inside your dwelling can have a very marked effect on your sound imho yes , that was my thinking. Many moons ago I used to have an earth spike in my garden, I'll have to do something similar again to compare the differences. Earthing regulations have always been a bit confusing to me so I will need advice to get it correct and safe.
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Post by pre65 on Nov 2, 2016 11:23:08 GMT
Are "earths" still bonded to water pipes ?
If so, would cleaning the connection area make a difference ?
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Post by Sovereign on Nov 2, 2016 12:21:50 GMT
Are "earths" still bonded to water pipes ?
If so, would cleaning the connection area make a difference ? They are If they are copper or steel, I cleaned all of my bonding straps a few years ago and made a nice difference , certainly opened up the sound a little with some improved top and sparkle.
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Post by Deleted on Nov 2, 2016 12:23:36 GMT
Sorry not wishing to give too much away here as we have solutions for customers.
A few years ago we were involved in a large project and a new build, the customer was looking for a complete solution mains wise.
Now PME earths are the norm these days and again quality depends on how close the return point is, how much local muck propagates into your supply.
The earth ground plane we designed used 2" O/D copper tubing in a 24 foot rectangle buried 5 feet down on a bed of wet builders sand around 12 inches, then various hard core before a 2foot (yes 2 foot) screed.
It was hooked up using armored cabling to a dedicated 8 way CU, the rest of the house (on totally separate CU) using the PME return system.
In total the main listening room had eight double switch-less sockets each feed by 6mm T & E (because we were working from the ground up much easier to route without question)via individual CB (all cyro treated and the CU)
The CU was feed by a custom built 20Kva BPT and sported a 230Vac regulation device plus several dedicated earth cleaning devices.
The noise floor on this system is still the lowest I have ever encountered by a significant margin even rivals my own with all the mains cleaning items I use.
However back in the here and now, mains earth does carry a significant amount of rubbish than can effect an audio system lmho
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Post by Sovereign on Nov 2, 2016 13:55:37 GMT
That's interesting reading. Did you coat the copper with anything before burying it to prevent corrosion?
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