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Post by Deleted on Jan 12, 2015 0:03:44 GMT
I'd just like to point out that the mains fuse in a power lead is there simply to stop the cable from turning into an electric fire element. Um - I think I said that further up the thread.... Craig |
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Post by Stratmangler on Jan 12, 2015 0:10:29 GMT
craig said: Um - I think I said that further up the thread.... Craig You probably did! I couldn't be bothered trawling through all the posts in the thread ..... |
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Post by pinkie on Jan 12, 2015 7:56:13 GMT
But it brings up another question: most of our gear takes fairly small current. Even a decent size power amp will never take more than 3A, or possibly extremely 5A for a monster class A. But I'll bet that we all just leave the good old 13A fuse in there, even when the mains cord is only (thermally) rated at perhaps 6A. I'd also wager that those who buy esoteric fuses from Hi-Fi Tuning and the like buy the 13A variety - at 30-odd quid a fuse you don't want the risk of one blowing as a result of transformer inrush current ;-) Russ Andrews has only adapted his own domestic system to US-style plugs and sockets - and as a private individual he can do whatever he feels comfortable with. As far as I know, there is no recommendation on the RA website to use anything other than regular UK plugs and sockets with fuses (with pricey cable between the two...) The only things that I turn off are the power amps - and that is only because it is valved, and I don't want a room heater running all the time, or feeding it with 8 matched pairs of valves regularly. Craig Regarding the 5 amp max, I had an interesting moment when I borrowed Arthurs Integral amp - with dire warnings of the only known working example, easy to fry due to no protection circuitry etc. I pulled the iee out of my quad, plugged it into the Integral, and... nothing! Oh s***. Several moments panic, wondering how to start the phone call, when I looked on the back of the amp which clearly says "must have a 10 amp fuse" (I had a 3 amp in the Quad lead). Phew! As for using US plugs (or EU ones) the issue is that there is circuit protection at the fuseboard to protect wires plugged in. However, with our lovely ring mains in the UK, where 13 amp cable in a ring can share the current arriving at a socket by taking 2 routes to get there, the board protection is at 30 amps. On a foreign radial circuit, with just one route to the socket the board protection is at 15 amps. It's that gulf between 30 and 13 compared with 15 and 13 that means we have to have a cartridge fuse in the UK. If you want to use an unfused foreign lead, to be safe you should do it on an appropriate radial circuit. |
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Post by Deleted on Jan 12, 2015 9:29:33 GMT
Regarding the 5 amp max, I had an interesting moment when I borrowed Arthurs Integral amp - with dire warnings of the only known working example, easy to fry due to no protection circuitry etc. I pulled the iee out of my quad, plugged it into the Integral, and... nothing! Oh s***. Several moments panic, wondering how to start the phone call, when I looked on the back of the amp which clearly says "must have a 10 amp fuse" (I had a 3 amp in the Quad lead). Phew! As for using US plugs (or EU ones) the issue is that there is circuit protection at the fuseboard to protect wires plugged in. However, with our lovely ring mains in the UK, where 13 amp cable in a ring can share the current arriving at a socket by taking 2 routes to get there, the board protection is at 30 amps. On a foreign radial circuit, with just one route to the socket the board protection is at 15 amps. It's that gulf between 30 and 13 compared with 15 and 13 that means we have to have a cartridge fuse in the UK. If you want to use an unfused foreign lead, to be safe you should do it on an appropriate radial circuit. The amp must not have had inrush protection. You need quite big fuses to stop them popping. On mine I have a 10 ohm 50W resistor in series with the 800VA toroid, which is short circuited after a second or so by a very large relay. Most big amps have a similar arrangement. The ring is an excellent point - my circuit breakers are 32A on the rings (just looked) - and (Wikipedia) the ring and fused mains socket were designed at the same time. The ring was introduced in the UK after WW2 to minimise copper use, and a fused plug was needed to overcome the high overall ring current requirements. There are a couple of spurs - to feed the cooker, and a dedicated one for the fridge and freezer. I have heard that many audiophiles install a spur to feed the audio system; maybe I ought to consider that more seriously. Anybody here gone this route? Craig |
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Post by MikeMusic on Jan 12, 2015 13:19:54 GMT
Seems the way to go
which I found out after our house refurb when I had a dedicated *ring* put in for the kit
Don't fancy ripping the cable out of the walls and redoing so it stays as is
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Post by Deleted on Jan 12, 2015 13:37:50 GMT
It is absolutely impossible for a mains fuse to have any effect on sound quality. Well, Jez, I'm not going to have a row about it, except that such absolutist statements put you at risk of looking a fool.
Oh, and my degree and the first half of my career were in electronic engineering. You're arguing that 13 A fuses effect the sound and think I'm the one risking looking like a fool... you couldn't make it up. Didn't know you were an EE but as such you should know better. Anyhow I'll just say that I am 100% certain that mains cables do not and cannot effect sound quality and neither do fuses and on that note, for the sake of forum harmony, I'll end my involvement in this thread. |
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Post by John on Jan 12, 2015 14:16:02 GMT
Jez in future just write in my professional opinion. You find it less likely to wind people up
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Post by Deleted on Jan 12, 2015 14:50:01 GMT
Well, Jez, I'm not going to have a row about it, except that such absolutist statements put you at risk of looking a fool.
Oh, and my degree and the first half of my career were in electronic engineering. You're arguing that 13 A fuses effect the sound and think I'm the one risking looking like a fool... you couldn't make it up. Didn't know you were an EE but as such you should know better. Anyhow I'll just say that I am 100% certain that mains cables do not and cannot effect sound quality and neither do fuses and on that note, for the sake of forum harmony, I'll end my involvement in this thread. Jez - you clearly did not read my rather detailed mail regarding the reason that mains cables can and do make a difference; you did not deal with any of those technical points, just reiterated your certainty. And if we're showing our technical and professional gonads - uk.linkedin.com/pub/craig-sawyers/5/43a/116/ |
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Post by pinkie on Jan 12, 2015 14:59:16 GMT
The amp must not have had inrush protection. You need quite big fuses to stop them popping. On mine I have a 10 ohm 50W resistor in series with the 800VA toroid, which is short circuited after a second or so by a very large relay. Most big amps have a similar arrangement. The ring is an excellent point - my circuit breakers are 32A on the rings (just looked) - and (Wikipedia) the ring and fused mains socket were designed at the same time. The ring was introduced in the UK after WW2 to minimise copper use, and a fused plug was needed to overcome the high overall ring current requirements. There are a couple of spurs - to feed the cooker, and a dedicated one for the fridge and freezer. I have heard that many audiophiles install a spur to feed the audio system; maybe I ought to consider that more seriously. Anybody here gone this route? Craig Spooky - spot on. The spooky bit was I'd just finished reading your post and Owen phoned to tell me he'd finally fixed his Integral (he designed the amplifier - not the productionisation). He was given an amp, but it blew early on, and he has only just got round to fixing it. And sure enough - no inrush protection was among the things he was having a rant about. I shall be interested to hear it in February - because he also has his latest power amp the AHB2 for me to listen to as well, and I can decide which one to make spaniel eyes about. |
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Post by pinkie on Jan 12, 2015 15:29:07 GMT
Time for a group, randomised control trial ? ? No - this is "foo". Let me qualify that. It is not to say those hearing it are wrong to experience what they experience, it is to observe that it is not repeatable or consistent. Not withstanding the transmission line theory of the subsequent post, the matter has not, as far as I can determine, ever been reliably demonstrated. I can measure that the voltage on my mains supply varies from day to day, and I can show that voltage variations in an amplifier affect sound, but it doesn't follow that a voltage variation on the mains used to power an amplifier will result in sound differences. (My own engineer friend would suggest if you want to do any measurements, to demonstrate an effect on sound quality, measure the output of the amplifier, not the input to its power supply) If a mains cable makes a difference - it should be capable of demonstration. It doesn't need elaborate test facilities. It doesn't need a theoretical justification. Just demonstration. Just one person who can hear the differences to get a score better than random from a sample of say 10 listening tests where they can't see and don't know which cable or fuse they are listening to. The problem is, those who are happy they can hear the difference, however "night and day" the difference is, usually only hear it when the system is warmed up, or burned in, or some other circumstances which invalidate a simple A:B test of the type I have been doing with the Pi recently. It would still be possible to devise a valid test, but it would need a lot of patience on the part of the demonstrator, and a live-in willing accomplice. So it doesn't happen. And we learn to live with the fact that on HiFi forums there will be those who are attracted to how they can improve their enjoyment of their system with these "special" features, and those like Jez and I who are unable to share the experience. I rather like Chris's snake handling post as a way of just dealing with letting those who enjoy the experience get on with it, and recognise I can't share it, and don't feel any loss. It's not so different from a school friends funeral I went to recently. Rather astonishingly for Kev, he had found God a few years ago, and become a very active part of what was a very demonstrative church. So a lot of his new friends were standing up and waving their arms and looking very trance like. And I was very happy for them, and happy to join in singing the hymns. They certainly seemed happy peaceful people. Again - plenty of "proof" was available - and I could have signed up for an Alpha course to learn it all and have even my most robust objections overturned. But I found myself unable to share the experience. And much the same applies with mains cables for me. But I feel no loss  |
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Post by MikeMusic on Jan 12, 2015 15:35:33 GMT
The ears have to be the decider
Mine decided mains cables improve my system very well indeed along with all sorts of barmy items like granite placemats on the kit - isn't that the furthest 'out there' ?
- Or the supports, Mana, RDC, Electric Beach, Stillpoints, Black Ravioli etc ?
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Post by MartinT on Jan 12, 2015 15:47:19 GMT
And if we're showing our technical and professional gonads LOL - love it, Craig! |
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Post by Deleted on Jan 12, 2015 15:56:58 GMT
The ears have to be the decider Mine decided mains cables improve my system very well indeed along with all sorts of barmy items like granite placemats on the kit - isn't that the furthest 'out there' ? - Or the supports, Mana, RDC, Electric Beach, Stillpoints, Black Ravioli etc ? Check. Oddly enough though, those in metrology and similar fields would find none of that surprising. I once got involved in doing the technology transfer of something called an Automatic Cryogenic Current Comparator Resistance Bridge (ACCCRB) from the NPL to Oxford Instruments. I was impressed with the lengths that they went too to reduce main's borne noise and structural vibration. First a double screened isolation transformer which penetrated the rear of the 19" rack. Then a custom triple screened toroid mounted in three nested and internally damped mutually insulated diecast boxes, with each screen 360 degree terminated to each box. Accessible through a hole in the box was a 10pF trimmer capacitor to fine tune the overall primary to secondary capacitance - which was around 0.01 pF. A bog-standard unscreened toroid will have about 1nF or more of primary/secondary capacitance. Now most real-world audio gear will not go for a box-triple-screened transformer and nested enclosures. So other techniques are necessary to prevent mains borne garbage from getting into our gear. Craig |
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Post by MartinT on Jan 12, 2015 16:11:49 GMT
I rather like Chris's snake handling post as a way of just dealing with letting those who enjoy the experience get on with it, and recognise I can't share it, and don't feel any loss. Nicely put, Richard. |
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Post by pinkie on Jan 12, 2015 16:13:44 GMT
The ears have to be the decider Mine decided mains cables improve my system very well indeed along with all sorts of barmy items like granite placemats on the kit - isn't that the furthest 'out there' ? - Or the supports, Mana, RDC, Electric Beach, Stillpoints, Black Ravioli etc ? Yes Mike, but as discussed on NLP and elsewhere it wasn't your ears. It was your brain. Helped by your eyes, and your experience, and the knowledge you'd got a lovely new bit of kit in there to listen to that would make your decision. Your HEARING made the decision. But a lot more than your ears were involved in what you heard. Same as the McGurk effect. It's really hard, and usually has to be quite contrived, just for your ears to decide.  |
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Post by MikeMusic on Jan 12, 2015 18:01:59 GMT
The ears have to be the decider Mine decided mains cables improve my system very well indeed along with all sorts of barmy items like granite placemats on the kit - isn't that the furthest 'out there' ? - Or the supports, Mana, RDC, Electric Beach, Stillpoints, Black Ravioli etc ? Check. Oddly enough though, those in metrology and similar fields would find none of that surprising. I once got involved in doing the technology transfer of something called an Automatic Cryogenic Current Comparator Resistance Bridge (ACCCRB) from the NPL to Oxford Instruments. I was impressed with the lengths that they went too to reduce main's borne noise and structural vibration. First a double screened isolation transformer which penetrated the rear of the 19" rack. Then a custom triple screened toroid mounted in three nested and internally damped mutually insulated diecast boxes, with each screen 360 degree terminated to each box. Accessible through a hole in the box was a 10pF trimmer capacitor to fine tune the overall primary to secondary capacitance - which was around 0.01 pF. A bog-standard unscreened toroid will have about 1nF or more of primary/secondary capacitance. Now most real-world audio gear will not go for a box-triple-screened transformer and nested enclosures. So other techniques are necessary to prevent mains borne garbage from getting into our gear. Craig So we're not finding the undiscovered. Many, many others have been there before |
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Post by jazzbones on Jan 12, 2015 18:05:42 GMT
I stand to be corrected on here by a closed and unbending mind or two, but didn't Michael Fremer, well know vinylist etc, familiar in audio circles., take up James Randi's (The Great Randi, Magician, debunker) offer of US$1,000,00.00c if someone could REPEATEDLY tell the difference and take up the challenge about audio cables, mains etc., making a difference. It appears that The Great Randi backed out of the contest... why was this, anyone know?
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Post by MikeMusic on Jan 12, 2015 18:05:57 GMT
Richard
I can't believe this mad stuff works.
If I take it out the sound degrades.
When I forgot to put the granite back on the Isis Friday with Martin I thought the sound was off in some way.
Granite back on, nice improvement.
If I take everything away the system will sound nothing like as good as it does now.
The other half often has no idea what I'm doing and always says
"the first (or second) sounded best"
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Post by MikeMusic on Jan 12, 2015 18:07:39 GMT
I stand to be corrected on here by a closed and unbending mind or two, but didn't Michael Fremer, well know vinylist etc, familiar in audio circles., take up James Randi's (The Great Randi, Magician, debunker) offer of US$1,000,00.00c if someone could REPEATEDLY tell the difference and take up the challenge about audio cables, mains etc., making a difference. It appears that The Great Randi backed out of the contest... why was this, anyone know? Be nice to know more He is annoying |
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Post by Deleted on Jan 12, 2015 18:12:40 GMT
OK folks... some are being less than pleasant on the whole matter so I'll re-join the fray.
First of all I do not believe this is a matter of personal opinion. It's either right or it's wrong. Expectation bias is completely to blame for the effects some believe they hear. Hundreds of years of scientific method and we're supposed to accept biased personal and wholly subjective opinion which can't be backed up with any form of verification?
I disagree with what Craig says about transmission lines. Starting where? A ferrite toroid with a few turns of the cable on it, close to the entry point to the case as a means of dealing with RFI is generally effective and I have no problem with this. This is irrelevant to most fancy cables though. The mains at the socket has not got thus far in a screened and correctly terminated impedance matched system and yet is supposed to be improved by the last 4' of cable??
Mains 13A fuses changing anything is just as ridiculous. If your mains supply, 13A fuse included, can power a 3KW appliance no problem then it's hardly going to be bothered by 400W drawn by your hifi. Is the 0.03 Ohm or so going to cause a problematic voltage drop? No. Is it going to have any effect on the AC waveform when not even remotely stressed by the load and at a frequency where thermal time constants are negligible? No. Can it effect the frequency of the mains? No. So if the mains emerges from the other side of the fuse at the same voltage and frequency and the probable 2% or more THD already present is not added to then the mains has not been effected and the sound can't change. In many of the amps I've designed and built the reservoir capacitance is such that after unplugging the amp it continues to play for, in some cases, nearly a minute. Rapidly switching the mains switch on and off has no audible effect... which says a lot about how sensitive to the mains supply the amp is.... It also kills any argument about the rectifiers only conducting for a small phase angle. I notice foolks still claim improvements from mains paraphernalia when a choke input filter is used and or a SMPS with active power factor correction etc.. either of which makes it much less likely still that the foo could work!
Then there is the voltage regulation, often used with further filtration before it, in the majority of equipment other than power amps and which will typically have 100dB of line rejection at lower audio frequencies. The power supply rejection ratio of most power amps and many pre amps also helps in rendering mains borne nasties less problematic.
An increasing proportion of equipment these days will also have a common mode choke in the input mains supply, almost de rigueur on a SMPS and not rare in conventional supplies. This will vastly reduce HF interference both entering and exciting the unit.
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