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Mains filters
Just a quick straw poll...
What are people's opinions of mains filters, upgraded power cables etc? Have been doing some investigation and there may actually be something in this. Not talking Russ Andrews style £250 mains cables here, more like sticking a plug with a filter onto a standard IEC lead, and possibly using one of those Masterplug RFI filtered 4-way blocks. Has anyone done any serious experimentation on this? I did hear a quite convincing demonstration at the Sound & Vision show in Bristol a few years ago, but the mains there is probably a lot dirtier than your typical home installation. What myself and a few others have figured out is that the level of RFI introduced onto your ring main by something like the switching PSU in a typical PC is quite high. Opinions, people? -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
Mains filters
"Glenn Richards" wrote in message . uk... Just a quick straw poll... What are people's opinions of mains filters, upgraded power cables etc? If you're going to upgrade your power cable you really ought to do it all the way back to the substation, otherwise it's a bit pointless... |
Mains filters
On Thu, 16 Mar 2006 00:39:53 +0000, Glenn Richards
wrote: Just a quick straw poll... What are people's opinions of mains filters, upgraded power cables etc? Have been doing some investigation and there may actually be something in this. Not talking Russ Andrews style £250 mains cables here, more like sticking a plug with a filter onto a standard IEC lead, and possibly using one of those Masterplug RFI filtered 4-way blocks. Has anyone done any serious experimentation on this? I did hear a quite convincing demonstration at the Sound & Vision show in Bristol a few years ago, but the mains there is probably a lot dirtier than your typical home installation. What myself and a few others have figured out is that the level of RFI introduced onto your ring main by something like the switching PSU in a typical PC is quite high. Opinions, people? You're really ready to believe, aren't you :-) Or is Squirrel thinking of moving into the magic cable market? |
Mains filters
On Thu, 16 Mar 2006 00:39:53 +0000, Glenn Richards
wrote: Just a quick straw poll... What are people's opinions of mains filters, upgraded power cables etc? Have been doing some investigation and there may actually be something in this. Not talking Russ Andrews style £250 mains cables here, more like sticking a plug with a filter onto a standard IEC lead, and possibly using one of those Masterplug RFI filtered 4-way blocks. Has anyone done any serious experimentation on this? I did hear a quite convincing demonstration at the Sound & Vision show in Bristol a few years ago, but the mains there is probably a lot dirtier than your typical home installation. What myself and a few others have figured out is that the level of RFI introduced onto your ring main by something like the switching PSU in a typical PC is quite high. Opinions, people? Glen,, please give it a rest. You aren't funny any more and this is all becoming just a little boring. d Pearce Consulting http://www.pearce.uk.com |
Mains filters
Rich Wilson wrote:
If you're going to upgrade your power cable you really ought to do it all the way back to the substation, otherwise it's a bit pointless... Well that was my initial thought... but apparently not. In a conversation I had with a friend, we determined that power cables are good at carrying low frequencies, and poor at carrying higher frequencies. So RFI picked up at the substation won't make it to your house, but interference sources in your house will cause RFI to reach your kit. For the record, at the moment my hi-fi equipment is plugged into a surge protected 4-way strip, nothing more elaborate. -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
Mains filters
Laurence Payne wrote:
Or is Squirrel thinking of moving into the magic cable market? Well, perhaps... ;-) I've figured out a method of constructing a filtered power cable for less than £10 materials cost, depending on quantity. Which, if the hi-fi mags are anything to go by, will sell for anything up to £60. And if it does make a perceptible difference, however tiny, that means £50 profit each time... -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
Mains filters
Don Pearce wrote:
Glen,, please give it a rest. You aren't funny any more and this is all becoming just a little boring. And herein lies the problem with this group. I ask a serious question, expecting some sensible responses, and instead all I get are sarcastic comments. The theory is sound anyway, if sticking an LCR filter across the mains input does indeed reduce the noise floor. As reducing the noise floor (by whatever means) improves dynamics. And this I have tested, I've recently been involved in cleaning up some recordings made about 25 years ago on analogue equipment. This process involves re-EQ followed by digital noise reduction, and the results before and after applying the noise reduction are nothing short of dramatic. This is using Nero Wave Editor (that comes with Nero Burning ROM), so no fancy expensive software. My question was a serious one, as it's obvious to anyone with any knowledge of audio that lowering the noise floor will improve the sound. So, I repeat. If you've got a lot of electrically noisy equipment on the same ring main as the hi-fi (eg switching power supplies in PCs etc) that's kicking out a lot of RF interference on the ring main, would it not follow that eliminating (or at least greatly reducing) this noise, and therefore providing a clean power feed to the amplifier and other equipment, would lower the noise floor? Once again, I'm not for a moment advocating spending £250 on something from Russ Andrews. What I'm actually talking about is getting a standard IEC lead for a couple of quid, then fitting a filtered 13A plug to it, also for a couple of quid. At trade prices in single quantities this will cost less than a fiver (which is actually less than you pay for a standard IEC cable at places like PC World). So, would someone like to provide a serious answer now? -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
Mains filters
On Thu, 16 Mar 2006 08:18:33 +0000, Glenn Richards
wrote: Don Pearce wrote: Glen,, please give it a rest. You aren't funny any more and this is all becoming just a little boring. And herein lies the problem with this group. I ask a serious question, expecting some sensible responses, and instead all I get are sarcastic comments. No, you were trolling. The theory is sound anyway, if sticking an LCR filter across the mains input does indeed reduce the noise floor. No it doesn't. Nobody who knows what they are talking about has ever told you any such thing. Did you make this up, or read it in one of the audio comics? As reducing the noise floor (by whatever means) improves dynamics. And this I have tested, I've recently been involved in cleaning up some recordings made about 25 years ago on analogue equipment. This process involves re-EQ followed by digital noise reduction, and the results before and after applying the noise reduction are nothing short of dramatic. Cleaning up recordings most certainly does *not* involve eq. That would be changing recordings. This is using Nero Wave Editor (that comes with Nero Burning ROM), so no fancy expensive software. My question was a serious one, as it's obvious to anyone with any knowledge of audio that lowering the noise floor will improve the sound. Read above - you can filter the mains til you turn blue and you won't change your noise floor by even a milli dB. So, I repeat. If you've got a lot of electrically noisy equipment on the same ring main as the hi-fi (eg switching power supplies in PCs etc) that's kicking out a lot of RF interference on the ring main, would it not follow that eliminating (or at least greatly reducing) this noise, and therefore providing a clean power feed to the amplifier and other equipment, would lower the noise floor? Turn your amplifier on, with no music playing and listen. Leave the volume control in the normal listening position and sit in your listening chair. What can you hear? Anything? Of course not. And what little hiss there is comes from the front end of the amplifier. None of it comes from the mains. Once again, I'm not for a moment advocating spending £250 on something from Russ Andrews. What I'm actually talking about is getting a standard IEC lead for a couple of quid, then fitting a filtered 13A plug to it, also for a couple of quid. At trade prices in single quantities this will cost less than a fiver (which is actually less than you pay for a standard IEC cable at places like PC World). So, would someone like to provide a serious answer now? Good old Russ Andrews - he has successfully conned £250 out of you. Now wise up and stop waving your stupidity like a flag of honour. d Pearce Consulting http://www.pearce.uk.com |
Mains filters
On Thu, 16 Mar 2006 10:39:13 +0200, "Iain Churches"
wrote: "Glenn Richards" wrote in message .uk... Just a quick straw poll... What are people's opinions of mains filters, upgraded power cables etc? Have been doing some investigation and there may actually be something in this. Not talking Russ Andrews style £250 mains cables here, more like sticking a plug with a filter onto a standard IEC lead, and possibly using one of those Masterplug RFI filtered 4-way blocks. Has anyone done any serious experimentation on this? I did hear a quite convincing demonstration at the Sound & Vision show in Bristol a few years ago, but the mains there is probably a lot dirtier than your typical home installation. What myself and a few others have figured out is that the level of RFI introduced onto your ring main by something like the switching PSU in a typical PC is quite high. Opinions, people? Hello Glenn. A couple of days ago, I popped in for 30 secs to an audio demo at a local dealership to take him some audition material. He was demonstrating a mains filter unit. He had a tunable RF gadget with a small inbuilt speaker which he plugged into a wall socket. Radio transmissions and very loud hash could clearly be heard. Then he plugged the gadget into one of the filtered outlets. Silence. It had a filter in it - what would you expect? This has nothing whatever to do with audio noise. The unit was about 4U in height, and had ten mains outlets on the rear panel. I was there for only a few seconds, (car parked on a yellow line) The dealer has promised me some literature. Regards to all Iain Don't be conned; there is no need. d Pearce Consulting http://www.pearce.uk.com |
Mains filters
In article , Glenn
Richards wrote: Just a quick straw poll... What are people's opinions of mains filters, upgraded power cables etc? That mains filters may be useful if you are having a problem with audible 'clicks and pops' from the mains, and can't suppress them at source. Ideally, though, the audio equipment is well enough designed to prevent such problems being audible. However, simply chainging 'mains cable' with no filter or surge suppressor is probably a waste of effort. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
Mains filters
"Don Pearce" wrote in message ... On Thu, 16 Mar 2006 10:39:13 +0200, "Iain Churches" wrote: "Glenn Richards" wrote in message t.uk... Just a quick straw poll... What are people's opinions of mains filters, upgraded power cables etc? Have been doing some investigation and there may actually be something in this. Not talking Russ Andrews style £250 mains cables here, more like sticking a plug with a filter onto a standard IEC lead, and possibly using one of those Masterplug RFI filtered 4-way blocks. Has anyone done any serious experimentation on this? I did hear a quite convincing demonstration at the Sound & Vision show in Bristol a few years ago, but the mains there is probably a lot dirtier than your typical home installation. What myself and a few others have figured out is that the level of RFI introduced onto your ring main by something like the switching PSU in a typical PC is quite high. Opinions, people? Hello Glenn. A couple of days ago, I popped in for 30 secs to an audio demo at a local dealership to take him some audition material. He was demonstrating a mains filter unit. He had a tunable RF gadget with a small inbuilt speaker which he plugged into a wall socket. Radio transmissions and very loud hash could clearly be heard. Then he plugged the gadget into one of the filtered outlets. Silence. It had a filter in it - what would you expect? This has nothing whatever to do with audio noise. The unit was about 4U in height, and had ten mains outlets on the rear panel. I was there for only a few seconds, (car parked on a yellow line) The dealer has promised me some literature. Regards to all Iain Don't be conned; there is no need. d Hi Don. I have a feeling you are right. In many years of large recording sessions, with hundreds of cables and interconnects I have never seen a mains filter unit in use. When I get the literature about the mains filter perhaps we can discuss this further. Glenn's post is IMO and interesting one. If there is a ghost to be laid to rest here, thsis is a good time and a good place to do it. Iain |
Mains filters
In article , Glenn Richards
wrote: Don Pearce wrote: Glen,, please give it a rest. You aren't funny any more and this is all becoming just a little boring. And herein lies the problem with this group. I ask a serious question, expecting some sensible responses, and instead all I get are sarcastic comments. The theory is sound anyway, if sticking an LCR filter across the mains input does indeed reduce the noise floor. I note the "if" qualifier in the above statement. :-) The problem is that you also need to know the source and load impedances in between which you are fitting any filter. e.g. if the load is essentially a short, then a shunt capacitance across it won't do much. The problem is that the source impedance can be expected to vary with location and frequency, and that the load impedance can be expected to vary during the mains cycle. Also, if you change the source impedance seen by the PSUs in the units you are trying to 'protect' you might cause some problems to become worse, not better. As reducing the noise floor (by whatever means) improves dynamics. This makes the unstated assumption that the PSU isn't already ensuring the 'noise' from the mains is - at the output of the unit - already so low as to be inaudible. [snip] So, I repeat. If you've got a lot of electrically noisy equipment on the same ring main as the hi-fi (eg switching power supplies in PCs etc) that's kicking out a lot of RF interference on the ring main, would it not follow that eliminating (or at least greatly reducing) this noise, and therefore providing a clean power feed to the amplifier and other equipment, would lower the noise floor? It may do so *if* the noise was previously at an audible level. It is easy enough to measure the output of a unit to look for signs of this - although simply listening and finding you can't actually hear anything may be a useful guide. The key point is that the designer of the equipment may well be sensible enough to know he/she lives in the real world, and will already have: 1) Designed the unit with a PSU that rejects mains interference to a suitable degree. 2) Designed the circuits in the unit so as to reject fluctuations on the power rails, and correctly references itself to the defined system ground level. Once again, I'm not for a moment advocating spending £250 on something from Russ Andrews. What I'm actually talking about is getting a standard IEC lead for a couple of quid, then fitting a filtered 13A plug to it, also for a couple of quid. At trade prices in single quantities this will cost less than a fiver (which is actually less than you pay for a standard IEC cable at places like PC World). So, would someone like to provide a serious answer now? There is unlikely to be any harm in buying and using some simple mains filters. Although note the caution I give above. FWIW I use 'RS' filtered blocks on the systems I use. The primary reason being that the Quad 34's I use are prone to picking up 'clicks' from the mains, and these filters dispose of the problem. As does the TV I use as a display in the living room. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
Mains filters
On Thu, 16 Mar 2006 10:58:37 +0200, "Iain Churches"
wrote: Don't be conned; there is no need. d Hi Don. I have a feeling you are right. In many years of large recording sessions, with hundreds of cables and interconnects I have never seen a mains filter unit in use. When I get the literature about the mains filter perhaps we can discuss this further. Glenn's post is IMO and interesting one. If there is a ghost to be laid to rest here, thsis is a good time and a good place to do it. Iain The problem is that this is a ghost that has been laid now many times, and every so often somebody comes along and insists on digging it up again, usually with some piece of pseudo science to back it up, as Glenn has. You are then torn - do you explain the engineering and science to somebody who is clearly not equipped to understand it, or simply tell them not to be stupid? Unfortunately, with Glenn the first option has been shown not to work. d Pearce Consulting http://www.pearce.uk.com |
Mains filters
In article , Iain Churches
writes "Glenn Richards" wrote in message .uk... Just a quick straw poll... What are people's opinions of mains filters, upgraded power cables etc? Have been doing some investigation and there may actually be something in this. Not talking Russ Andrews style £250 mains cables here, more like sticking a plug with a filter onto a standard IEC lead, and possibly using one of those Masterplug RFI filtered 4-way blocks. Has anyone done any serious experimentation on this? I did hear a quite convincing demonstration at the Sound & Vision show in Bristol a few years ago, but the mains there is probably a lot dirtier than your typical home installation. What myself and a few others have figured out is that the level of RFI introduced onto your ring main by something like the switching PSU in a typical PC is quite high. Opinions, people? Hello Glenn. A couple of days ago, I popped in for 30 secs to an audio demo at a local dealership to take him some audition material. He was demonstrating a mains filter unit. He had a tunable RF gadget with a small inbuilt speaker which he plugged into a wall socket. Radio transmissions and very loud hash could clearly be heard. Then he plugged the gadget into one of the filtered outlets. Silence. The unit was about 4U in height, and had ten mains outlets on the rear panel. I was there for only a few seconds, (car parked on a yellow line) The dealer has promised me some literature. Regards to all Iain Yes please publish it here for all the see, and see also what snake oil he used to do that with. Total bollockx!..... -- Tony Sayer |
Mains filters
Don Pearce wrote:
I ask a serious question, expecting some sensible responses, and instead all I get are sarcastic comments. No, you were trolling. No, I was asking a serious question. As reducing the noise floor (by whatever means) improves dynamics. And this I have tested, I've recently been involved in cleaning up some recordings made about 25 years ago on analogue equipment. This process involves re-EQ followed by digital noise reduction, and the results before and after applying the noise reduction are nothing short of dramatic. Cleaning up recordings most certainly does *not* involve eq. That would be changing recordings. By "cleaning up" I was referring specifically to applying digital noise reduction. The re-EQ was mentioned simply for completeness, as the recordings were a bit bass-shy and lacking in sparkle. So a touch of smiley EQ solves that, followed by noise reduction. It's rather vital that you EQ before NR though, otherwise the re-EQ boosts bits that the NR has cut, leading to some interesting pumping effects... Read above - you can filter the mains til you turn blue and you won't change your noise floor by even a milli dB. On an average setup in an average domestic residence I'm sure that's the case. Unfortunately I have a dozen or so PCs, all with switching power supplies, sat in the next room, spewing RF onto the ring main. Which in theory could be affecting the sound... at least in theory. Turn your amplifier on, with no music playing and listen. Leave the volume control in the normal listening position and sit in your listening chair. What can you hear? Anything? Of course not. And what little hiss there is comes from the front end of the amplifier. None of it comes from the mains. You can't hear much above 20kHz. But signals at frequencies above this will affect what you do hear, harmonics, interaction etc. Why do you think there's been so much work done on DVD-A, SACD etc, using sample rates of 96kHz or even 192kHz, rather than 44.1? Good old Russ Andrews - he has successfully conned £250 out of you. Read my earlier postings. Currently I'm just using a standard IEC cable, running into a surge protected (not even an RFI filtered) 4-way strip. Surge protected for obvious reasons... I don't want a rogue power spike frying 2 grand's worth of kit. Now wise up and stop waving your stupidity like a flag of honour. You are Stewart Pinkerton and I claim my five pounds. -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
Mains filters
Don't be conned; there is no need.
d Hi Don. I have a feeling you are right. In many years of large recording sessions, with hundreds of cables and interconnects I have never seen a mains filter unit in use. Nope pro audio people are a tad less neurotic then Joe hi-fi public!.... When I get the literature about the mains filter perhaps we can discuss this further. Glenn's post is IMO and interesting one. If there is a ghost to be laid to rest here, thsis is a good time and a good place to do it. Iain -- Tony Sayer |
Mains filters
Don Pearce wrote:
The problem is that this is a ghost that has been laid now many times, and every so often somebody comes along and insists on digging it up again, usually with some piece of pseudo science to back it up Just a thought... If I were to replace my Ethernet cables with triple-shielded OFC, and use a £250 IEC cable to connect my PC to the mains, do you think it would lower the noise floor in this group? -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
Mains filters
On Thu, 16 Mar 2006 09:10:30 +0000, Glenn Richards
wrote: Don Pearce wrote: I ask a serious question, expecting some sensible responses, and instead all I get are sarcastic comments. No, you were trolling. No, I was asking a serious question. As reducing the noise floor (by whatever means) improves dynamics. And this I have tested, I've recently been involved in cleaning up some recordings made about 25 years ago on analogue equipment. This process involves re-EQ followed by digital noise reduction, and the results before and after applying the noise reduction are nothing short of dramatic. Cleaning up recordings most certainly does *not* involve eq. That would be changing recordings. By "cleaning up" I was referring specifically to applying digital noise reduction. The re-EQ was mentioned simply for completeness, as the recordings were a bit bass-shy and lacking in sparkle. So a touch of smiley EQ solves that, followed by noise reduction. It's rather vital that you EQ before NR though, otherwise the re-EQ boosts bits that the NR has cut, leading to some interesting pumping effects... Read above - you can filter the mains til you turn blue and you won't change your noise floor by even a milli dB. On an average setup in an average domestic residence I'm sure that's the case. Unfortunately I have a dozen or so PCs, all with switching power supplies, sat in the next room, spewing RF onto the ring main. Which in theory could be affecting the sound... at least in theory. Turn your amplifier on, with no music playing and listen. Leave the volume control in the normal listening position and sit in your listening chair. What can you hear? Anything? Of course not. And what little hiss there is comes from the front end of the amplifier. None of it comes from the mains. You can't hear much above 20kHz. But signals at frequencies above this will affect what you do hear, harmonics, interaction etc. Why do you think there's been so much work done on DVD-A, SACD etc, using sample rates of 96kHz or even 192kHz, rather than 44.1? Good old Russ Andrews - he has successfully conned £250 out of you. Read my earlier postings. Currently I'm just using a standard IEC cable, running into a surge protected (not even an RFI filtered) 4-way strip. Surge protected for obvious reasons... I don't want a rogue power spike frying 2 grand's worth of kit. Now wise up and stop waving your stupidity like a flag of honour. You are Stewart Pinkerton and I claim my five pounds. That is the end of that then. You are not an engineer - you have never been an engineer and you can never be an engineer. So for goodness sake stop posting stuff that is trying to sound like engineering when it is in fact unmitigated balls. I already told you, it is no longer funny. Stick to whatever it is you know about. d Pearce Consulting http://www.pearce.uk.com |
Mains filters
On Thu, 16 Mar 2006 09:14:39 +0000, Glenn Richards
wrote: Don Pearce wrote: The problem is that this is a ghost that has been laid now many times, and every so often somebody comes along and insists on digging it up again, usually with some piece of pseudo science to back it up Just a thought... If I were to replace my Ethernet cables with triple-shielded OFC, and use a £250 IEC cable to connect my PC to the mains, do you think it would lower the noise floor in this group? Not while you are posting, it wouldn't. Stop now and lower the noise floor by 20dB. d Pearce Consulting http://www.pearce.uk.com |
Mains filters
tony sayer wrote:
I've never ever had a problem with dodgy mains and audio equipment apart from a very many years ago now when early solid state amps were around and for that matter haven't been able to affect my system at all with locally generated RF fields, except with the exception of the QUAD ESL's where you can trigger the protection with an RF signal. Nice! The main reason I was asking... as I said in an earlier post, because I work from home I've got about a dozen PCs sitting in the next room, on the same ring main as the hi-fi. Which makes one wonder just how much crap is getting onto the mains. I would generally be of the opinion that if you've got a "normal" setup at home (one PC, turned on when needed) filtering etc probably wouldn't make a difference. But when you're sat next door to a scaled down version of Telehouse you probably do want some filtering. I'm currently using a standard Masterplug 4-way surge strip for obvious reasons, but you can get an RFI filtered version for about £8 trade. Which is about 2 quid more than the unfiltered surge protected version, so as I'm going to need another surge strip shortly, I might well "risk" a couple of quid. If it doesn't make any difference, it doesn't matter, it's less than the cost of a pint. Nope, its just another area where people like Russ A sell all manner of exotic junk to the feeble minded to con them out of their moolah, and if he gets away with it, more fool them!....... This is the problem with places like Russ Andrews. *If* upgrading the mains cable makes a difference, it'll be the filtered plug that does it. Which you can buy for a couple of quid, and fit to a standard IEC or figure 8 cable, or even chop off the moulded plug and fit to the captive lead on cheaper kit. Although if it's the filtering that makes the difference, just use one of those Masterplug surge/RFI strips and leave the moulded plug. So you can get exactly the same improvement (if there is one - while I'm convinced on speaker cables and interconnects I'm still a little sceptical about power cables) with less than a tenner's worth of bits as you can with a £250 cable, how many bottles of snake oil are Russ Andrews bundling with that cable? The biggest problem with the snake oil merchants of course is that it makes everyone sceptical of what could possibly be a genuine improvement. -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
Mains filters
"Don Pearce" wrote in message ... On Thu, 16 Mar 2006 09:10:30 +0000, Glenn Richards wrote: Don Pearce wrote: I ask a serious question, expecting some sensible responses, and instead all I get are sarcastic comments. No, you were trolling. No, I was asking a serious question. As reducing the noise floor (by whatever means) improves dynamics. And this I have tested, I've recently been involved in cleaning up some recordings made about 25 years ago on analogue equipment. This process involves re-EQ followed by digital noise reduction, and the results before and after applying the noise reduction are nothing short of dramatic. Cleaning up recordings most certainly does *not* involve eq. That would be changing recordings. By "cleaning up" I was referring specifically to applying digital noise reduction. The re-EQ was mentioned simply for completeness, as the recordings were a bit bass-shy and lacking in sparkle. So a touch of smiley EQ solves that, followed by noise reduction. It's rather vital that you EQ before NR though, otherwise the re-EQ boosts bits that the NR has cut, leading to some interesting pumping effects... Read above - you can filter the mains til you turn blue and you won't change your noise floor by even a milli dB. On an average setup in an average domestic residence I'm sure that's the case. Unfortunately I have a dozen or so PCs, all with switching power supplies, sat in the next room, spewing RF onto the ring main. Which in theory could be affecting the sound... at least in theory. Turn your amplifier on, with no music playing and listen. Leave the volume control in the normal listening position and sit in your listening chair. What can you hear? Anything? Of course not. And what little hiss there is comes from the front end of the amplifier. None of it comes from the mains. You can't hear much above 20kHz. But signals at frequencies above this will affect what you do hear, harmonics, interaction etc. Why do you think there's been so much work done on DVD-A, SACD etc, using sample rates of 96kHz or even 192kHz, rather than 44.1? Good old Russ Andrews - he has successfully conned £250 out of you. Read my earlier postings. Currently I'm just using a standard IEC cable, running into a surge protected (not even an RFI filtered) 4-way strip. Surge protected for obvious reasons... I don't want a rogue power spike frying 2 grand's worth of kit. Now wise up and stop waving your stupidity like a flag of honour. You are Stewart Pinkerton and I claim my five pounds. That is the end of that then. You are not an engineer - you have never been an engineer and you can never be an engineer. So for goodness sake stop posting stuff that is trying to sound like engineering when it is in fact unmitigated balls. I already told you, it is no longer funny. Stick to whatever it is you know about. d Don. Have you taken your Andrew's liver salts this morning? You are sounding like a grumpy old man:-) It's a beautiful sunny day here. I am just off for a morning walk down to the sea with the Airedale. Regards to all. Iain |
Mains filters
On Thu, 16 Mar 2006 11:33:07 +0200, "Iain Churches"
wrote: Don. Have you taken your Andrew's liver salts this morning? You are sounding like a grumpy old man:-) It's a beautiful sunny day here. I am just off for a morning walk down to the sea with the Airedale. Regards to all. Iain I am a grumpy old man - that is what keeps me so happy. Today it is trying to snow, and I am about to go for a walk down to Sainsbury's to get some food. Just heard a thing on the radio about the London olympics in 2012, so that is another excuse for me to snarl at people. Does anybody - apart from those unmentionable lycra-wearers - give a flying stuff about the Commonwealth Games? The opening ceremony was on telly last night, and what little I saw was truly bizarre; definitely not to be switched on during the next two weeks or whatever. d Pearce Consulting http://www.pearce.uk.com |
Mains filters
"Glenn Richards" wrote in message ... Rich Wilson wrote: If you're going to upgrade your power cable you really ought to do it all the way back to the substation, otherwise it's a bit pointless... Well that was my initial thought... but apparently not. In a conversation I had with a friend, we determined that power cables are good at carrying low frequencies, and poor at carrying higher frequencies. So RFI picked up at the substation won't make it to your house, but interference sources in your house will cause RFI to reach your kit. That actually isn't true. Until recently, when the amateur radio community, via first the R.A. and then Ofcom, managed to get it stopped, there were tests of a system call PLT ( power line transmission ). This system placed RF carriers up to about 30MHz, onto the domestic mains supply. The purpose was for data transmission of the broadband internet variety. However, no matter how balanced the mains supply is, it still isn't good enough to prevent common mode currents at these sorts of frequencies, and therin lies one of the major problems with this technology. The whole mains supply network, from the injection point at the substation, to your house, has a tendency to radiate like a dammed great antenna, at times causing serious interference to legitimate receiving equipment - and thats not a hifi, it's a radio. It was eventually determined that there were better, more efficient, and less troublesome technologies available for broadband delivery, and dropped, at least here, although I believe that there may still be some places in Europe where the tests are still happening. Bear in mind also, that the generating and distribution companies, use this, or a similar high frequency technology, in-house to carry telemetry data around their grid distribution network. So, just to recap, the mains power distribution system can successfully carry HF, as well as LF, all the way to your house. As far as interference escaping from your equipment goes, it certainly shouldn't, under strict EU regulations. Any electrical / electronic equipment sold in the EU, should carry CE certification, and one of the requirements of this certification, is that the equipment does not either send crap out onto the mains, above a certain very low level, nor directly radiate it. Further, the equipment's normal performance must not be compromised in any way, by the presence of high level RF or pulse interference, either introduced into any outside-world ports, the mains supply being one such, or by direct radiation. So again, to recap. If the equipment is reasonably recent, and the manufacturer is playing by the rules, it should not feed any crap onto the mains supply. If your hifi manufacturer has played by the rules, his kit should not respond to any such crap, that got onto the mains by any route. All that said, there's no harm at all in helping your kit out by fitting a surge arrester plug, which contains VDRs, and if you find a good one, it should have RF suppression in the form of LCR in it, as well. Worth a tenner for the surge protection at least, and the ' belt and braces ' for the filtering that should already be in your kit, but I certainly wouldn't pay any more. Even then, I would probably spend the rest of the week trying to work out if my money would have been better spent on 4 pints ... Arfa |
Mains filters
Arfa Daily wrote:
In a conversation I had with a friend, we determined that power cables are good at carrying low frequencies, and poor at carrying higher frequencies. So RFI picked up at the substation won't make it to your house, but interference sources in your house will cause RFI to reach your kit. That actually isn't true. Until recently, when the amateur radio community, via first the R.A. and then Ofcom, managed to get it stopped, there were tests of a system call PLT ( power line transmission ). This system placed RF carriers up to about 30MHz, onto the domestic mains supply. This technology actually exists (possibly at a different frequency), and works very well. About 18 months ago some student friends asked me if I could get broadband around their shared house. First thoughts were WLAN of course, so I duly ordered a broadband account for them, and set up a wireless router in a central location, with wireless cards in all the PCs and laptops allowing everyone to access the internet through it. Unfortunately, it was a rather large house, and there was a huge dead spot on the ground floor. So... enter HomePlug. Whacked a HomePlug powerline networking bridge into the router via wired Ethernet, and plugged a HomePlug access point in on the ground floor in the middle of the dead spot. Which solved the problem. All that said, there's no harm at all in helping your kit out by fitting a surge arrester plug, which contains VDRs, and if you find a good one, it should have RF suppression in the form of LCR in it, as well. Worth a tenner for the surge protection at least, and the ' belt and braces ' for the filtering that should already be in your kit, but I certainly wouldn't pay any more. Even then, I would probably spend the rest of the week trying to work out if my money would have been better spent on 4 pints ... From a purely objective point of view, it's worth spending a tenner (of a fiver trade) on a surge protected strip to protect 2 grand's worth of kit, especially if you happen to live somewhere where there's dodgy power. Yay rural areas... -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
Mains filters
It was eventually determined that there were better, more efficient, and
less troublesome technologies available for broadband delivery, and dropped, at least here, although I believe that there may still be some places in Europe where the tests are still happening. Bear in mind also, that the generating and distribution companies, use this, or a similar high frequency technology, in-house to carry telemetry data around their grid distribution network. What over the 475 kV grid?, don't you mean via the fibre optic at the top running along the "aerial" earth wire?.... -- Tony Sayer |
Mains filters
Don Pearce wrote:
So for goodness sake stop posting stuff that is trying to sound like engineering when it is in fact unmitigated balls. I already told you, it is no longer funny. Stick to whatever it is you know about. So the bottom line is that you don't believe RFI filtering will make a difference. Why didn't you just say that? Why did you have to resort to posting all that crap, in response to what was quite a serious question? What really is no longer funny is that when one posts a question or observation on this group that doesn't quite fit within the narrow viewpoints of certain people that think they own and run this newsgroup, all hell breaks loose, making it impossible to have a civilised discussion about anything at all. Because there's always someone who will disagree with subject "x" enough to start hurling personal insults around. If your opinion is that filtering won't make a difference, state your opinion, avoid personal insults, and let civilised debate commence. Sadly there doesn't appear to be a uk.rec.hi-fi where those of us who can tell the difference between bell wire and 105-strand speaker cable can have a discussion about which cable sounds best with which equipment, without the likes of yourselves or Pinkerton (to name but two) chiming in with "********" or words to that effect. We've got uk.rec.audio.vinyl now, why not have uk.rec.audio.hi-fi or audiophile as well? -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
Mains filters
"Iain Churches" wrote in message ... "Don Pearce" wrote in message ... On Thu, 16 Mar 2006 10:39:13 +0200, "Iain Churches" wrote: Hi Don. I have a feeling you are right. In many years of large recording sessions, with hundreds of cables and interconnects I have never seen a mains filter unit in use. A lot of Pro equipment includes a mains filter as part of the IEC mains socket. I have VDRs fitted to the plugs feeding all my audio and computer equipment, as I've found it helps reduce the number of unexplained lock-ups, when only a power cycle will unlock the kit. I only get one or two a year now, as opposed to one or two a month without them. I do live out in the sticks, so my supply may well have less urban hash on it, but possibly more surges. S. |
Mains filters
Don Pearce wrote:
Not while you are posting, it wouldn't. Stop now and lower the noise floor by 20dB. Pinkerton? Is that you? :-P -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
Mains filters
In article , Glenn Richards wrote:
In a conversation I had with a friend, we determined that power cables are good at carrying low frequencies, and poor at carrying higher frequencies. So RFI picked up at the substation won't make it to your house, but interference sources in your house will cause RFI to reach your kit. How do you determine the electrical properties of cables by conversation? Rod. |
Mains filters
In article , Glenn Richards wrote:
I've figured out a method of constructing a filtered power cable for less than £10 materials cost, depending on quantity. Which, if the hi-fi mags are anything to go by, will sell for anything up to £60. And if it does make a perceptible difference, however tiny, that means £50 profit each time... And when it is discovered that it makes no difference whatsoever...? Rod. |
Mains filters
In article , Glenn Richards wrote:
The theory is sound anyway, if sticking an LCR filter across the mains input does indeed reduce the noise floor. Maybe it would be if it did, but it doesn't, so it isn't. It's nonsense. Rod. |
Mains filters
In article , Glenn Richards wrote:
The main reason I was asking... as I said in an earlier post, because I work from home I've got about a dozen PCs sitting in the next room, on the same ring main as the hi-fi. Which makes one wonder just how much crap is getting onto the mains. Mains is full of crap anyway. Have you ever looked at it with a scope? Sometimes it looks nothing whatsoever like those neat sinewaves in the textbooks, but the power supplies in any electronic equipment running from it will transform it, rectify it, filter it and stabilise it and thereby turn it into clean DC for the electronics itself because that's what power supplies do. Filtering the mains will have no additional benefit. Rod. |
Mains filters
"Glenn Richards" wrote in
message Don Pearce wrote: Glen,, please give it a rest. You aren't funny any more and this is all becoming just a little boring. And herein lies the problem with this group. I ask a serious question, expecting some sensible responses, and instead all I get are sarcastic comments. The theory is sound anyway, No its not. Contrary to some naive beliefs, there is not a direct connection from your power line to your speaker cable. Here's a news flash: there is a fair amount of active and passive circuitry between your power line and your speaker cable. if sticking an LCR filter across the mains input does indeed reduce the noise floor. It doesn't. For one thing there already is a massive LCR filter accross the mains input in just about every piece of gear. It's called the power supply. As reducing the noise floor (by whatever means) improves dynamics. If you want to reduce the noise floor - then why not address the cause of the noise in the first place? Hint: the source of noise in properly-designed audio equipment *isn't* leakage from the power line. And this I have tested, I've recently been involved in cleaning up some recordings made about 25 years ago on analogue equipment. This process involves re-EQ followed by digital noise reduction, and the results before and after applying the noise reduction are nothing short of dramatic. Hint: the source of the noise in those old recordings wouldn't have been helped by power line filters. This is using Nero Wave Editor (that comes with Nero Burning ROM), so no fancy expensive software. You're taking a good idea and running off to China with it. My question was a serious one, as it's obvious to anyone with any knowledge of audio that lowering the noise floor will improve the sound. Not if the noise floor is already below audibility. And reducing the noise floor in your stereo will do no good if it is already lower than the noise floor in the recordings you play. So, I repeat. If you've got a lot of electrically noisy equipment on the same ring main as the hi-fi (eg switching power supplies in PCs etc) that's kicking out a lot of RF interference on the ring main, would it not follow that eliminating (or at least greatly reducing) this noise, and therefore providing a clean power feed to the amplifier and other equipment, would lower the noise floor? Flawed premise. Switching power supplies in PCs don't kick a lot of RF interference into the mains. They have built in line filters that prevent that from happening. PC's are widely used for audio production and testing. They generally don't compromise those environments. Once again, I'm not for a moment advocating spending £250 on something from Russ Andrews. What I'm actually talking about is getting a standard IEC lead for a couple of quid, then fitting a filtered 13A plug to it, also for a couple of quid. At trade prices in single quantities this will cost less than a fiver (which is actually less than you pay for a standard IEC cable at places like PC World). Do a sighted evaluation of this idea. I'm sure you'll get positive results. So, would someone like to provide a serious answer now? Trust me, if improving sound quality was this easy, it would have been done all over the place. And in some sense it has - by the plain ordinary power supplies in regular audio gear. |
Mains filters
"Roderick Stewart" wrote in message om... In article , Glenn Richards wrote: I've figured out a method of constructing a filtered power cable for less than £10 materials cost, depending on quantity. Which, if the hi-fi mags are anything to go by, will sell for anything up to £60. And if it does make a perceptible difference, however tiny, that means £50 profit each time... And when it is discovered that it makes no difference whatsoever...? Rod. This won't affect sales in the slightest. Rod. My local dealer, a good friend of mine, sells high-end mains cables for EURO 850 each. He has no stock, and so nothing to "sell" but people still insist on ordering them! Iain |
Mains filters
In article ,
Don Pearce wrote: Turn your amplifier on, with no music playing and listen. Leave the volume control in the normal listening position and sit in your listening chair. What can you hear? Anything? Of course not. And what little hiss there is comes from the front end of the amplifier. None of it comes from the mains. You've never heard things like a fridge splat etc which is mains borne? Of course it depends on the design of the power supply in your amp, etc. I've got a dedicated radial circuit with its own earth feeding my AV equipment. -- *I used up all my sick days so I called in dead Dave Plowman London SW To e-mail, change noise into sound. |
Mains filters
"tony sayer" wrote in message ... It was eventually determined that there were better, more efficient, and less troublesome technologies available for broadband delivery, and dropped, at least here, although I believe that there may still be some places in Europe where the tests are still happening. Bear in mind also, that the generating and distribution companies, use this, or a similar high frequency technology, in-house to carry telemetry data around their grid distribution network. What over the 475 kV grid?, don't you mean via the fibre optic at the top running along the "aerial" earth wire?.... -- Tony Sayer To Glenn. You've virtually answered your own question there about whether the mains wiring can successfully handle HF as well as RF, although I was not actually referring to broadband distribution around the house, rather to its delivery from the ISP, and this technology has, at least for the time being, been knocked on the head here, because of potential interference issues. To Tony. You're right. In recent years, the electricity companies have installed fibre optic links, but I'm fairly sure that when they first started using this method of communicating amongst themselves, they did make use of the full distribution network, including the supergrid, but I may be wrong on that. How much power volts are on the line, shouldn't make any difference. It's still just a piece of wire, with HF skin effect, to the comms signal. I believe that with the PLT internet trials, the injection points were at central substations, so I guess that this must have been working at up to at least the local 11kV distribution level. Just as an aside, I think that the grid and supergrid operate at 275kV and 400kV, not 475kV. I also have a dim recollection of reading somewhere, that the 25kV overhead lines on the uk rail nework, were also used for HF telemetry, but again, I could be going off on one there. Suffering from CRAFTs disease, don'tcha know ... !! d;~} Arfa |
Mains filters
"Glenn Richards" wrote in message . uk... Don Pearce wrote: I ask a serious question, expecting some sensible responses, and instead all I get are sarcastic comments. No, you were trolling. No, I was asking a serious question. As reducing the noise floor (by whatever means) improves dynamics. And this I have tested, I've recently been involved in cleaning up some recordings made about 25 years ago on analogue equipment. This process involves re-EQ followed by digital noise reduction, and the results before and after applying the noise reduction are nothing short of dramatic. Cleaning up recordings most certainly does *not* involve eq. That would be changing recordings. By "cleaning up" I was referring specifically to applying digital noise reduction. The re-EQ was mentioned simply for completeness, as the recordings were a bit bass-shy and lacking in sparkle. So a touch of smiley EQ solves that, followed by noise reduction. Professionals call this "cosmetic enhancement" :-)) For one's own use, make any changes that take your fancy. For a commercial release, I regard the smiley brigade with deep distrust. When the big day comes and we all standing in line in the big mastering room in the sky, they will have much to answer for:-) It's rather vital that you EQ before NR though, otherwise the re-EQ boosts bits that the NR has cut, leading to some interesting pumping effects... That's correct. One needs to do a dummy run though to see if the pre-EQ is the best possible after you have heard the NR. I do quite a lot of "shellac recovery" Once the surface noise has been removed, people often get the impression that the HF has been peeled off also. In actual fact there was probably very little HF above 6-8kHz there to start with. So in these instances I do the NR first. Any subsequent gentle EQ slightly raises the noise floor, but with vintage material is of little consequence. The secret is to do as little as possible In this instance less is often more :-) regards to all Iain |
Mains filters
Is this the reason why one of my amps has its own power supply. A separate
box that sits next to the pre-amp and transforms the mains into DC? -- John the West Ham fan "Roderick Stewart" wrote in message om... In article , Glenn Richards wrote: The main reason I was asking... as I said in an earlier post, because I work from home I've got about a dozen PCs sitting in the next room, on the same ring main as the hi-fi. Which makes one wonder just how much crap is getting onto the mains. Mains is full of crap anyway. Have you ever looked at it with a scope? Sometimes it looks nothing whatsoever like those neat sinewaves in the textbooks, but the power supplies in any electronic equipment running from it will transform it, rectify it, filter it and stabilise it and thereby turn it into clean DC for the electronics itself because that's what power supplies do. Filtering the mains will have no additional benefit. Rod. |
Mains filters
On Thu, 16 Mar 2006 11:14:28 +0000 (GMT), "Dave Plowman (News)"
wrote: In article , Don Pearce wrote: Turn your amplifier on, with no music playing and listen. Leave the volume control in the normal listening position and sit in your listening chair. What can you hear? Anything? Of course not. And what little hiss there is comes from the front end of the amplifier. None of it comes from the mains. You've never heard things like a fridge splat etc which is mains borne? Of course it depends on the design of the power supply in your amp, etc. I've got a dedicated radial circuit with its own earth feeding my AV equipment. No - never heard a thing come through the mains. If I started hearing stuff now, I wouldn't be buying mains filters - I'd be fixing the wiring. d Pearce Consulting http://www.pearce.uk.com |
Mains filters
On Thu, 16 Mar 2006 11:17:50 GMT, "housetrained"
wrote: Is this the reason why one of my amps has its own power supply. A separate box that sits next to the pre-amp and transforms the mains into DC? All amps have their own power supply that does exactly this. Whether it is in the same box or not is entirely immaterial. d Pearce Consulting http://www.pearce.uk.com |
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