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In Reply to: RE: Not sure I understand your point posted by E-Stat on May 11, 2008 at 14:06:43
Obviously the point I made is: any degradation in signal quality happenning entirely due to design sins found internal to a piece of gear would be completely irrelevant to the signal degradation being caused by grid issues propagating through an improperly designed power supply. It's pretty simple really. You made a comment to mkuller about how people always concentrate on grid issues when they should be worrying about internal problems. I merely pointed out the obvious that this is irrelevant to the topic of discussion since the topic of discussion IS grid issues.
Now, clearly the statement you made: "as found at my outlets" is ridiculous because why in the hell would the OP care about what is at your outlets, but even still what would be really amusing is watching you try and convince me or anyone that somehow your power conditioner prevents grid issues from getting to your outlets. In fact, that would be funny I bet.
Since you obviously consider yourself special in some way as to be unaffected by grid issues, which BTW is impossible as I pointed out in a post below unless you are recieving power from an alternative power source other than the grid, here is an experiment for you to try which should allow you to see why it isn't true no matter how great the filtering your conditioner has. While you are listening to tunes unplug this conditioner you have from the grid over several hours listen to see if there is ever a difference in sound quality. If there s ever in the course of time a change in sound quality due to unplugging the power conditioner then you to ar obviously affected by at least the grid issue you just simulated, ie the unfortunate but fairly common downed power line blackout condition.
Follow Ups:
Obviously the point I made is: any degradation in signal quality happenning entirely due to design sins found internal to a piece of gear would be completely irrelevant.
My comments remain on the AC in a typical home, not a component's power supply. The sins to which I refer are the various sources of noise generated back into your AC line by all sorts of digital devices that live within modern homes like computers, routers, access points, DVD/CD players, TiVOs, mobile and cellular phones, etc.
While you are listening to tunes unplug this conditioner you have from the grid over several hours listen to see if there is ever a difference in sound quality.
The problem with your experiment is that it assumes there is only one variable - the grid - which is not the case. Regardless of the quality of the grid, there is always a difference in my environment due to internally generated noise.
rw
"The sins to which I refer are the various sources of noise generated back into your AC line by all sorts of digital devices that live within modern homes like computers, routers, access points, DVD/CD players, TiVOs, mobile and cellular phones, etc."
I understand what you are saying however I disagree that this is an internal issue when you are talking about noise from a another device on the power line not even the device under test. As you point to, we are talking about waveforms which are conducted "BACK" onto the line which therefore will mix in with the AC power signal supplied by the utility to create something other than what was intended to be sent by the utility. The ripple induced back on the signal supplied by the power company due to things like back emf from switcher coils and the regulation issues caused by having a highly variable load impedance in the form of the input to a switching power supply at the end of an impperfect transmission grid are generally not going to be a problem for the device with the switching supply causing the problems due to the fact that these switchers will have a control frequency granularity well up out of the audible range and therefore very succesfully filter these types of issues out of audio signals but it will be a huge problem for other devices with circuit topologies that aren't so adept with these types of waveform anomalies and end up mixing these ripple noises into their own audio signals. The types of equipment very susceptible will be the standard audiophile gear employing a good old fashioned linear power supply which due to cost cutting may get trimmed to low iron/copper winding content transformers and tiny little filter capacitances and low cost off the shelf linear regulators which when taken as a whole power supply circuit are simply incapable of filtering the problems. The point is that whether the problem comes from the device sitting next to the device under test or the neighbors house or some device accross town it doesn't really matter since once it is "BACK" on the line it is a grid issue not an internal one.
"The problem with your experiment is that it assumes there is only one variable - the grid - which is not the case. Regardless of the quality of the grid, there is always a difference in my environment due to internally generated noise."
Rather I see my experiment as well enough thought out to isolate the effect which I am intending to study. I think if you read back throuh my post you will find that in no way have I denied that noise and distortion due to internal circuit problems don't exist. On the contrary I have merely been attempting to keep a discussion about apples off the topic of oranges.
make sure all components use switching supplies to make sure the grunge emitted by the others doesn't affect a non-switching supply component. I guess that works if you like switching amps. :)
The types of equipment very susceptible will be the standard audiophile gear employing a good old fashioned linear power supply which due to cost cutting may get trimmed to low iron/copper winding content transformers and tiny little filter capacitances...
And what constitutes "tiny little filter capacitances"?
Rather I see my experiment as well enough thought out to isolate the effect which I am intending to study.
Go right ahead and study. Meanwhile, others may be interested in real world systems.
rw
"make sure all components use switching supplies to make sure the grunge emitted by the others doesn't affect a non-switching supply component."
Not at all. If you asked me I think rick_m nailed it below. By holding both the equipment manufacturers whos equipment causes these problems as well as the utilities whos power quality it is that ends up sucking both to high enough standards along with requireing a minimum level of design excellence in the form of grid issue immunity from the device under test manufacturers all combined could lead to the most ideal situation.
"I guess that works if you like switching amps. :)"
Well I like what theory says switching amps have to offer, but even I'll admit that existing practical applications leave alot to be desired in most cases. I say give it 20 years and see what you say then.
"And what constitutes "tiny little filter capacitances"?"
It's all relative right? Take a look inside any cheapo yamaha HTIB million dot one reciever for illustration. Give me a set of standards outlining worst case expected operating conditions, again I think rick_m said it best, to design to and I'll tell you what your necessary capacitance will be. From govt. ill-regulated utilities to cheap chinese crap switchers plastered with CE stickers you know couldn't have come within a million miles of a certified CE test lab without blowing out the recieve circuits on the test gear the problem right now is that the "standards" just don't exist in practice.
"Go right ahead and study. Meanwhile, others may be interested in real world systems."
You lost me here.On the one hand my amps for example have what may be arguably about some of the most robust power supplies ever produced in some audio gear but at the same time I know that within milliseconds of a blackout my sound is gonna suck bigtime. It doesn't bother me a bit and I'd never put a power conditioner in front of them since I'd have to spend a fortune in order to to not choke them out and also since they already do a dandy job filtering 99.99% of what is coming down the line at them to a level that is working well enough for me. I'm just going to have to live without tunes during blackouts at least until that permit for my backyard nuclear power generator plan goes through with the city.
is their high level of parasitic inductance. The self-resonant frequency is low, so they are ineffective filters for audio-band, let alone RF, noise.
As Andy already rightly pointed out: paralleling the large caps with much higher self resonant frequency low ESR(usually much smaller package size) parts along with using an appropriate power and ground plane will allow excellent filtering up into the GHz range. Obviously the honking caps are meant for the low frequency disturbances not the high frequency ones but since apparently low and high frequency problems are present we need both. The good news is since these GHz frequencies are likely mostly going to be generated externally to the boxes I own and not internally they will be very filterable from entering the box in the first place by using what I would consider low footprint low cost filters such as your own powerline RC's not to mention the big trannys in most of my equipments power supplies wont pass these signals very well even if they are present at the primaries.
In a power amp, the inductance of the wires that connect the filter caps to the output device collectors/drains is much greater than that of the filter caps themselves. An exception would be if the caps are of the snap-in type that mount on the same board as the output devices. Local bypass capacitors of around 100uF, physically close to the output device collectors/drains give a low-inductance path to ground in this application and eliminate the problem. Marshall Leach's page on power supply bypassing describes an interesting thing that happens when these have a value that's too small.
By holding both the equipment manufacturers whos equipment causes these problems as well as...
Great idea for the next generation of electrical components that may take decades to develop. Meanwhile, the real world beckons and requires action.
Give me a set of standards outlining worst case expected operating conditions, again I think rick_m said it best, to design to and I'll tell you what your necessary capacitance will be.
And yet, that will likely not be entirely what is required. Effective RFI trapping requires more than a big filter bank.
You lost me here.
Your "disconnect-conditioners-to-check-the-grid" idea continues to ignore the current reality of RFI. As for me, if I were to bypass my conditioners (and conditioning power cords), then it would always seem that the grid is noisy.
On the one hand my amps for example have what may be arguably about some of the most robust power supplies ever produced in some audio gear...I'd never put a power conditioner in front of them since I'd have to spend a fortune in order to to not choke them out
I'll certainly agree here. I use conditioners on front end components only. For high current amplifiers (my VTL amps have triple the energy storage of a 6290), I use aftermarket power cords.
rw
"Great idea for the next generation of electrical components that may take decades to develop. Meanwhile, the real world beckons and requires action."
Do I strike you as a politician or something? I'm doing my best at the voting booths. You gotta start somewhere.
"Effective RFI trapping requires more than a big filter bank."
Not true. A good designer will be able to create a filter that works out near the GHz range down to somewhere slightly above DC using nothing more than the transformer and various capacitor types along with good PCB layout which includes parallel power and ground planes. Anything above a GHz will most likely be coming from somewhere external to the design for typical well designed audio equipment. Low footprint filters and shielded boxes will nearly eliminate these issues. See my response to Al for more details of my opinions on this. The near DC issues are the ones that are a real bitch to deal with without throwing major cash at. Luckily here in Seattle area near DC issues are fairly rare so I am fairly satisfied.
"Your "disconnect-conditioners-to-check-the-grid" idea continues to ignore the current reality of RFI. As for me, if I were to bypass my conditioners (and conditioning power cords), then it would always seem that the grid is noisy."
No offense but I can't help but wonder if this problem could largely be resolved by using better design techniques more appropriate to the RF problems you describe. Not saying I know anything about the quality of your paricular equipment, but in my experience thse types of problems can be engineered into the zone of being non issues but it takes a slightly different type of engineer, RF engineer, than what are typically found designing audio gear and/or the in house grid wiring layout.
but differ as to the solution. I have a collection of pretty nice components (detailed if you are interested by clicking my moniker). Arguably, if each one were re-engineered, then some of the issues I face could be addressed. Meanwhile, I'm trying to fix what's there! :)
rw
It would appear that you are correct. Thanks for bearing with me long enough for me to catch a glimpse of another viewpoint. After looking back at my original post, it looks a tad aggressive. Not to make excuses but sometimes foreign viewpoints can be a little discomforting at first. Cheers.
rw
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