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Hi,
What is the technical basis for power conditioning, AC purifiers, etc.?
Several very reputable manufacturers of high end components do not recommend using any them (actually stating it is best to NOT use them). I have also read quite a few posts stating that a high quality power supply should isolate a component from AC issues.
Does this mean that under voltage, over voltage, and line surges within a reasonable tolerance are a non-issues? What about noise on the AC line?
Is there any scientific/technical justification for spending money on power conditioners, re-generators, filters, and such?
L.
Follow Ups:
See:
http://www.audioasylum.com/audio/cables/messages/82423.html
and the URL's it references as well.
This should do for a starter.
Jon Risch
** What is the technical basis for power conditioning, AC purifiers, etc.? **
Power factor correction, voltage spikes, surges, RFI and EMI. Ironically many of the garden variety products specify their capability in these areas. But as you may have guessed, many audiophile vendors leave their spec's up to the users' imagination.
Compare Furman spec (mainstream )
http://www.furmansound.com/product.php?div=02&id=IT-REF_20i
to Shuntaya's (audiophile)
http://www.shunyata.com/Content/technical-HydraVrayspecs.html
** I have also read quite a few posts stating that a high quality power supply should isolate a component from AC issues. **
Some probably do, but as with many other audiophile products with zero (or near zero) specs, there is little guidance. Stuff like power factor correction, and surge suppression are fairly standard stuff that should be specified. I will rather go with mainstream mfr on stuff like this, an ineffective product could prove very costly in the event of real AC issue.
Music making the painting, recording it the photograph
There's an interesting web page that shows the internals of a Shunyate Hydra Model-4 here . The manufacturer's literature of this device claims that it contains a "7-element 'Venom filter'". LOL!
The device has a garden variety circuit breaker in series, along with 0.1uF filter capacitors and metal oxide varistors (MOVs) across the outlets. The author of the above site lists the part numbers of the MOVs and capacitors. The Littelfuse MOV data sheet PDF can be found here . The part is in the fourth row under "standard models" (P/N TMOV20R130E). The Vishay capacitor data sheet PDF can be found here . It is in the last row (P/N F1710-410-10XX). The listed value of 0.01uF appears to be a misprint. It should be 0.1uF.
The capacitors are of the type specifically rated for mains operation. They have the property that if their maximum voltage rating is exceeded and they fail, they won't catch fire.
The MOVs act like an open circuit until they reach a critical voltage, above which they begin to act like a short. The original GE MOV application note from 1972 can be found here . Looking at the Littelfuse MOV data sheet, it appears that they begin to conduct (1 mA current) at a minimum peak voltage of 184 Volts. This happens to be the peak value of a 130VAC sine wave (they are rated at 130VAC). Also, it looks like they can withstand peak currents of up to 100A, which occurs at a maximum voltage of 340V peak.
The Furman device that theaudiohobby mentions above looks much more sophisticated. It appears to completely regenerate the AC.
Hi Andy,
This 10 Audio article has come up several times and been answered on these forums before in great detail. However, I will offer another reply here to answer the issues you raise, since you have referenced that article.
> > > "There's an interesting web page that shows the internals of a Shunyate Hydra Model-4 here. The manufacturer's literature of this device claims that it contains a "7-element 'Venom filter'". LOL! < < <
In 2005 I declined Mr. 10's offer of a "review" in exchange for us loaning him products. His response to my decline was clearly one of someone being affronted. He said with emphasis that he would get our product some other way and review it without our cooperation. It doesn't take more than a cursory read to see the effect my decline had on the tone and content of his comments.
He "reviewed" a product that was a long out of spec product by 2005, so there is no surprise that his photo's didn't match what we were producing, or the listed spec's on our web at that time. I wish once in a while people would question just for a moment, and not simply accept web-made-up negative information as accurate without looking a bit further. This fellow plowed ahead without question because we 'failed to accommodate' him.
There have been many advances within our products since the pictured H4 was made in 2002 and an entire board constructed with the multi-element filter array that is both pictured and described in detail on our web. That network did not exist within the first production run model that 10 likely purchased used, and wrote about in '05. Our listed specs and tech have been _exactly_ accurate on our web related to current production every step of the way.
> > "The device has a garden variety circuit breaker in series, along with 0.1uF filter capacitors and metal oxide varistors (MOVs) across the outlets." < < <
This is inaccurate. We use a Carling electro-magnetic breaker and there is nothing cheap or pedestrian about it. It is an extremely expensive part compared to any other type of breaker, thermal or otherwise on the market. And we do not use anybody's shelf capacitors, wiring or outlets. The capacitors are custom designed and bear our name. The outlets are our own design and spec, and the wiring is made for us to spec. out of solid CDA 101 copper. We have our own cryo treatment facility, our own connectors and multiple patents covering materials and technologies. 10 wanted to turn his "review" of a legitimate product into a home-depot project because of his angst.
Calling Hydras "Audiophile" products clearly skips the fact that they are more widely used in prominent professional recording, film and mastering studios than any other product of their kind--though Equitech has many applications in Pro as well.
Our industry reference list, professional endorsements and listed technologies are as well documented and explained as any product on the market could be. Yet all it takes is some ill-informed blogger with a chip on his shoulder to provide fodder for those eager to support their own perceptions.
Anyone with legitimate questions of any sort are always welcome to contact us directly. We have a well earned reputation among even the most (previously) skeptical engineers and electronics manufacturers who use and endorse our products. Our patents and tech are there for all to review and critique.
Regenerative products work great in theory. We don't believe they are as effective in practice. That said, I think both Furman and Equitech make excellent transformer based products. However, they are no more nor less technically legitimate than the products we produce without them.
Regards,
Grant
Shunyata Research
Power Plant Premier
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Power Products > Power Plant Premier
PS Audio Power Plant Premier
Dimensions
- 17" W x 16.5" D x 4" H
Weight
- 35 lbs
Nominal Input Voltage
- 105-135 (US) 215-245VAC (Europe/Asia)
Maximum Continuous Load
- 1200VA (US) 1500VA (Europe/Asia)
Dynamic Power Delivery
- 0.5 second > 3600VA (US) 5000VA (Europe/Asia)
Voltage Regulation
- +/- 0.5V (US) 1Vac (Europe/Asia)
Output Distortion Input 220-240VAC
- 1200VA Resistive load <0.9%
Output distortion 230V
- 240VAC 1200VA Reactive* load <0.9%
Output Distortion Input 110-130VAC
- 1200VA Resistive load <0.5%
Output distortion Input 110-130VAC
- 1200VA reactive load <0.5%
Output impedance
- <0.015 Ohm
Noise reduction (all zones)
- 100KHz-2MHz > 80dB
Efficiency @1200VA
- Resistive load > 80% Reactive load > 85%
Input Frequency
- 45-65Hz
Under voltage limit
- 90VAC (US) - 175VAC (Europe/Asia)
Over voltage limit
- 145VAC (US) - 275VAC (Europe/Asia)
Protection Modes
- L-N, L-G, N-G
Energy dissipation
- 2160J (US) 2142J (Europe/Asia)
Peak Current surge
- 144,000A (US) 84,000A (Europe/Asia)
Max Surge
- 6,000 Volts
Clamp level
- 330V (US) 800V (Europe/Asia)
Telco protection
- 320 Joules 395 volts
Coax insertion loss
- <1dB
DC trigger config
- Tip positive
DC trigger Voltage
- 5-15 volts dc
From Equitech
Model Q Specifications
.
Model #
Model
Name Load
Capacity
Input Line
Frequency
LIne Cord Plug
Chassis Inlet **
Output
Voltage
Circuit
Breakers
# Outlets
Type
Chassis
Dimensions
Weight
1RQ Q1000
1 kVA 15A 120V
60Hz
NEMA 5-15
C14
120/60V
1-10A 12-15A
16"x16"x3.5"
60 lbs
27 kg
1RQ-E
Q1000E
1 kVA
10A 230V
50/60Hz See Table
C14
230/115V
1-5A
12-C13 16"x16"x3.5"
40 x 40 x 8.75cm
60 lbs
27 kg
1.5RQ 1.5Q
1.5 kVA 15A 120V
60Hz
NEMA 5-15
C14
120/60V
1-15A 12-15A
16"x16"x3.5" 80 lbs
38 kg
2RQ 2Q
2 kVA 20A 120V
60Hz
NEMA 5-20
C20
120/60V
1-20A 10-15A
2-20A
16"x16"x3.5" 85 lbs
40 kg
2RQ-E
2QE
2 kVA
10A 208/240V
50/60Hz
See Table
C14
230/115V
1-10A
12-C13
16"x18"x5.25"
40 x 45 x 12.75cm
91 lbs
42 kg
2RQ-EA
2QEA
2 kVA
10A 208/240V
50/60Hz
See Table
C14
120/60V
1-20A
10-15A
2-20A 16"x18"x5.25"
40 x 45 x 12.75cm
91 lbs
42 kg
3RQ 3Q
3 kVA 20A 208/240V
60Hz
NEMA 6-20
C20
120/60V 1-10A
1-20A 10-15A
2-20A
16"x18"x5.25" 105 lbs
48 kg
3RQ-E
3QE
3 kVA
16A 208/240V
50/60Hz
See Table
C20
230/115V
1-5A
1-10A
10-C13
2-C19 16"x18"x5.25"
40 x 45 x 12.75cm
112 lbs
51 kg
3RQ-EA
3QEA 3 kVA
16A 208/240V
50/60Hz See Table
C20
120/60V 1-10A
1-20A 10-15A
2-20A 16"x18"x5.25"
40 x 45 x 12.75cm
112 lbs
51 kg
5RQ 5Q
5 kVA 30A 208/240V
60Hz
NEMA L6-30P
120/60V 1-10A
2-20A 14-15A
4-20A
17.25"x18"x7"
175 lbs
80 kg
5RQ-E
5QE
5 kVA
30A 208/240V
50/60Hz NEMA L6-30P 230/115V
1-5A
2-10A
13-C13
4-C19 17.25"x18"x8.75"
43 x 45 x 22cm
195 lbs
89 kg
5RQ-EA 5QEA
5 kVA 30A 208/240V
50/60Hz
NEMA L6-30P
120/60V 1-10A
2-20A 14-15A
4-20A
17.25"x18"x8.75"
43 x 45 x 22cm
195 lbs
89 kg
7.5RQ
7.5Q
7.5 kVA
40A 208/240V
60Hz
California Style
2P3W 50A 250V 120/60V 4-20A 16-15A
8-20A 17.25"x18"x8.75"
220 lbs
100 kg
7.5RQ-E 7.5QE
7.5 kVA 40A 208/240V
50/60Hz California Style
2P3W 50A 250V 230/115V 4-10A
14-C13
6-C19 17.25"x18"x8.75"
43 x 45 x 22cm
235 lbs
107 kg
7.5RQ-EA
7.5QEA
7.5 kVA
40A 208/240V
50/60Hz California Style
2P3W 50A 250V 120/60V 4-20A 16-15A
8-20A 17.25"x18"x8.75"
43 x 45 x 22cm
235 lbs
107 kg
10RQ 10Q
10 kVA 50A 208/240V
60Hz
California Style
2P3W 50A 250V 120/60V 5-20A 20-15A
10-20A 17.25"x18"x8.75" 245 lbs
111 kg
10RQ-E
10QE
10 kVA
50A 208/240V
50/60Hz California Style
2P3W 50A 250V 230/115V
5-10A
17-C13
8-C19 17.25"x18"x8.75"
43 x 45 x 22cm
260 lbs
118 kg
10RQ-EA 10QEA
10 kVA 50A 208/240V
50/60Hz California Style
2P3W 50A 250V
120/60V 5-20A 20-15A
10-20A
17.25"x18"x8.75"
43 x 45 x 22cm
260 lbs
118 kg
It's like you've been fed this line so long you actually believe that there isn't a higher standard which could/should be strived for. To me your logic is the equivalent of the following: as long as we are still making money as a lumber mill it is OK that bandsaw operators are lopping off fingers on our bandsaw that had the safety guard removed to improve throughput since we can always send them to the hospital to be rpaired as long as we dig the finger out and sew it back on quick enough.
Don't you think the problem of "grid issues" would be more effectively solved by redirecting the efforts of designing the worlds most perfect band aids toward designing equipment which doesn't require a band aid in the first place?
I have to ask if you even know who you are responding too here and why?
> > Lumping power conditioner manufacturers into the group called "audiophile vendors" sounds like a sick joke to me.> >
Where did *I* do that?
> > It's like you've been fed this line so long you actually believe that there isn't a higher standard which could/should be strived for. To me your logic is the equivalent of the following: as long as we are still making money as a lumber mill it is OK that bandsaw operators are lopping off fingers on our bandsaw that had the safety guard removed to improve throughput since we can always send them to the hospital to be rpaired as long as we dig the finger out and sew it back on quick enough.
Don't you think the problem of "grid issues" would be more effectively solved by redirecting the efforts of designing the worlds most perfect band aids toward designing equipment which doesn't require a band aid in the first place?> >
All I did was show that a few manufacturers of Power conditioners that are marketed toward the high end did in fact list relevant specs contrary to what the previous poster was asserting. Why are you babbling about band saws, band aided and grid issues?
This thread is a perfect example....
Your response to theaudiohobby's complaint
"But as you may have guessed, many audiophile vendors leave their spec's up to the users' imagination. "
is nothing but power conditioner specs to which I respond (quoted below), obviously jumping to the conclusion you were posting examples of audiophile vendors truly supplying complete specs on their audio equipment by supplying very complete specs to some power conditioners as a counterargument to theaudiohobby's original claim:
"Lumping power conditioner manufacturers into the group called "audiophile vendors" sounds like a sick joke to me."
to which you've responded with the intelligence revealing gem:
"Where did *I* do that?"
LOL! good stuff just like the other thread you bring up! Unfortunately, for me the comedy has likely now played its course. At least others who read this will understand why I stop responding here in the absence of the addition of at least a small kernel of an intelligent argument even if you don't Scott.
Cheers buddy. Thanks again for a good chuckle. Seriously.
Ugly
> > This thread is a perfect example....
Your response to theaudiohobby's complaint
"But as you may have guessed, many audiophile vendors leave their spec's up to the users' imagination. "> >
Dude, seriously, what are you sniffing? More to the point who are you quoting? This is audiohobby's post to which i responded in whole.
"In Reply to: RE: AC Power posted by Lynn on May 07, 2008 at 19:36:47
** What is the technical basis for power conditioning, AC purifiers, etc.? **
Power factor correction, voltage spikes, surges, RFI and EMI. Ironically many of the garden variety products specify their capability in these areas. But as you may have guessed, many audiophile vendors leave their spec's up to the users' imagination.
Compare Furman spec (mainstream )
http://www.furmansound.com/product.php?div=02&id=IT-REF_20i
to Shuntaya's (audiophile)
http://www.shunyata.com/Content/technical-HydraVrayspecs.html
** I have also read quite a few posts stating that a high quality power supply should isolate a component from AC issues. **
Some probably do, but as with many other audiophile products with zero (or near zero) specs, there is little guidance. Stuff like power factor correction, and surge suppression are fairly standard stuff that should be specified. I will rather go with mainstream mfr on stuff like this, an ineffective product could prove very costly in the event of real AC issue."
Dude, get a clue!!!!!!
> > Dude, get a clue!!!!!! < <
Scott, in order to have a clue, you need to have ACTUAL AUDIO experience, and considering that Ugly always bases his "opinions" on nothing more than speculation ... well ... your asking far too much of him.
TB1
Whatsa matta loser? You hafta resort to personal insults since you have nothing to offer in the form of technical input? Classy! At least Scott is trying....
your instantly defensive, perhaps I struck a nerve.
OK ... Mr. Ugly, the subject is AC based noise reduction within an audio environment, so exactly how many PLCs have you heard to form your 'em ... informed opinion?
trying
TB1
OOOoo. Whos getting defensive?No need to ruin my sound and listen to your crappy PLC's. I am achieving rated SNR and have no known noise issues beyond what is expected from the equipment I use during normal low volume listening sessions. Why would I insert something guaranteed to have a negative impact on signal quality if it isn't needed? The only issues that mys system won't filter by design are extreely low frequency, ie brown outs, etc and show up more as a temporary reduction of dynamic range capabilities rather than a noise you might hear. I could help you design a system that allows you to reach your noise goals too but it'll cost you about $120 an hour including tax, and then you could use your PLC's for boat anchors like they are better at doing.
To put it another way. You can't afford the PLC setup I'd need to make an actual improvement in my system and neither can I. It would probably be cheaper to set up an alternative power source in my case as the power draw can approach several KW during peak transients. The ways I am often inclined to listen, while sipping a beer on the neighbors porch for example, will often require nearly that in RMS power as well.
> > To put it another way. < <
Well, Ugly, thats the beauty of living in your complete fantasy world, you can "put it" anyway you want.
TB1
I can see that your technical prowess will just be too much for me to overcome. Uncle.
As I suspected, not only are you stuck with trying to communicate using babay talk, it appears that any sentence more complex than a few words will throw you for a loop. Here is a hint: read my posts slowly and several times. What I said makes sense to those who understand English. Is English even your native language?
I'd rather be water boarded.
Suit yourself.
Even if your equipment had perfect RF noise rejection built in to its power supplies, the RF noise present on the power cords may still be coupled to the interconnect and speaker cables. RF noise may get into equipment through any port and affect the audio signal.
IME, it is important that the power cords and cables be damped as well as shielded, so that they do not support RF ringing modes. These modes are especially troublesome if they overlap and make the coupling among cables stronger. Filtering the noise on the AC is helpful in the feed to the audio system and at the noise-generating appliances. These days, almost all appliances contain switching power supplies and computers, and generate noise continuously as they wait for the user to push a button.
most guys here still harp on the "miles and miles" argument about the power sub station and completely ignore the villains from within.
rw
What would be irrelevant and off topic would be to bring up "villains from within" in a discussion about power from the grid.
The subject of the thread, "AC Power", as found at my outlets (that which is relevant to audio components) is not the same as the power coming from the grid.
rw
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.
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
...since blind tests have shown you can't hear the difference anyway, my inexpensive audio system sounds just as good as your high end stuff.
So there!
like *voodoo* and *witchcraft*. :D
rw
IMHO the need for "power conditioning" is tied to how we distribute power and audio signals. We need to get away from the idea of our power/signal traveling through a grounded conducter.
Everyone understands how balanced audio can help reject noise. Some might argure that it isn't required in the home environment but I doubt many would say it hurts. By the same token we should be running our power in a "balanced" distribution system. In American this is cheap and easy. Simply rewire your gear to use 240VAC and plug it into the correct wall outlet. If your gear can use 240VAC then you have to spend money and buy a center tapped transformer.
It does make a difference. Do remember that we typically "create" the noise on the power lines and that it isn't "made" at the local utility.
Russ
P.S. I owe some an apology but the good news is I did find that CD and should be able to mail it on Monday.
a
"What is the technical basis for power conditioning, AC purifiers, etc.?"
To a certain degree the performance of any device running on grid power will be dictated by the quality if that power. Of course power problems will be more evident with some designs as judged by system performance but all designs will be slave to it at some level.
"Several very reputable manufacturers of high end components do not recommend using any them (actually stating it is best to NOT use them)."
Most likely since they know that most wont understand how to properly design in equipment light footprint yet effective and and improper design could negatively effect of the component they sold you. Since power conditioning done well can get quite spendy depending on just how far it is taken, it will typically be designed in with a system in mind in order to not overspend but still give the necessary grunt to do the job. I would also like to point out that solutions do not have to be expensive to be effective at soving certain power quality issues but to go all the way will get spendier and spendier the closer you get to perfect.
"I have also read quite a few posts stating that a high quality power supply should isolate a component from AC issues."
I disagree and would say that a power supply can do nothing more than filter grid issues. For example even a rechargeable battery driving an AC power generator needs to recharge off the grid eventually. IMO the only true isolation would require an alternate energy source.
"Does this mean that under voltage, over voltage, and line surges within a reasonable tolerance are a non-issues? What about noise on the AC line?"
Depends on your definition of reasonable and what exactly your solution ends up being. Keeping in mind that spending more doesn't always equal better, in general the more you are able to spend on the job the more ideal the solutions available to you with a completely alternative power source being the limit.
"Is there any scientific/technical justification for spending money on power conditioners, re-generators, filters, and such?"
I would say sure but I would warn that doing the job in a way that truly does improve overall performance without breaking the bank takes an expert/pro. Not every item on the market is applicable for every application.
"I disagree and would say that a power supply can do nothing more than filter grid issues. For example even a rechargeable battery driving an AC power generator needs to recharge off the grid eventually. IMO the only true isolation would require an alternate energy source."
Sounds more like a semantic problem than an engineering one since the only thing required is that power supplies adequately "filter grid issues". If a stereo component is incapable of performing to specification without external power conditioning then it is simply defective or deficient.
The rub of course is the specifications, specifically that there are none. Lacking any enforced standard for power supply rejection and any useful standard for performance the consumer bears all the risk and expense. I sure wish Stereophile would pick up the cudgel on this issue and start measuring power supply rejection and EMC. It isn't difficult and would be a real service to everyone concerned with high-end audio.
Rick
Well put, and you raise several good points.
So, in the absence of specifications what does a consumer do, and how bad do issues on the grid have to be to cause a problem for properly designed equipment?
From an engineering view, what is reasonable in terms of rejection and what is the 'sound' of leakage? Is it just higher SNR?
Until there are standards, is it safe to say that most high end equipment from mainstream manufacturers have solid designs that preclude the need for conditioning (with a 'reasonable' level of AC issues)?
Thank you. And you pose excellent questions, to which unfortunately I haven't very cogent answers.
As audiophile consumers we do the main thing right now by trying to verify the equipment's suitability for our needs in our environment prior to final purchase commitment. We could also do informal relative testing when comparing gear. How close can you get with a transmitting cell or cordless phone before you hear interference? Plug something with a brush motor into the same circuit and see if you hear it with headphones. Sniff around with an AM radio to get an idea of how much noise it generates. That sort of thing.
As far as the sound I'm not very qualified to speak to that, clearly other posters have spent a lot more effort in that area than I have. But I've enough experience to say that it runs the gamut from gross to so subtle that you feel more than hear it. On the gross side, my power amp sits within 18" of our refrigerator compressor on the other side of the wall. After living here a week and wondering if I'd end up with one of the speaker cones in my lap, I trotted down to the supply house and bought a tripp-lite filter to see if that would help temporarily. It did, and I've never bothered to do better although I obviously should put snubbers on the relays. But that was a matter of survival, not sound. On the subtle end I switched to an LCD monitor last year in my study where I use my computer as the source. I don't think I can describe the difference but it just didn't sound as good with the new monitor plugged in. I've got a "bad" arrangement where the computer and stereo are on the same circuit but on adjacent walls and I feed the audio over with a cable. I suspected that it was injecting noise into the ground loop formed by the monitor's signal and power cables along with the power line and audio feed. So I shuffled some connections around and found an arrangement that minimized the problem.
Obviously much of the problem is driven by system topology. Using unbalanced interconnects is bad. Using in-band power is bad. But good engineering can conquer all. I would suppose that high-end manufacturers may pay attention to these areas since they can limit system performance. Mass manufacturers with CE qualified equipment may be pretty good also. And for us consumers... there's always Z-beads and conditioners.
On my "one of these days" list I have looking into these issues in more detail. For me that means measurement and correlation. If I ever do it I will be able to provide some realer answers, albeit limited in scope.
Regards, Rick
A small voice of dissension here. Since AC noise on the grid can vary, it is difficult for manufacturers to develop a conditioner to address all issues, not to mention expensive. To be sure there are a few: I believe some of the later Mark Levinson gear is supposed to have a power re generator built in, as well as the Halcro stuff. Their prices are rather high, though.
In order to make affordable gear, most manufacturers opt for decent, but not state of the art filtering. My guess is that to admit that, would be akin to admitting that their designs are not good, and I believe some simply ignore the aftermarket units or reject them as being a criticism of their designs. Even today there are no conditioners I have tried (of the affordable ones, that is) that can address every conceivable power grid issue. Some work better than others with some gear, some don't work at all. I've plugged in one conditioner into another for some spectacular gains, but others are not so cumulative and certainly environmental factors change the effectiveness. Even battery powered units change their sound as the batteries discharge and the discharge rate can vary over time (haven't played with the lead acid types, but it certainly applies to lithium and nicad types). And then there are the rather voodoo stuff......
Stu
Hi Stu,
Yes, not knowing what's running around on the power lines is a problem. While it would serve the common-good to know and control it, that would require the services of a functional government. Meanwhile if the consumer had access to comparative performance data then the "market" could make a more informed decision. Having reviewers use fancy conditioners and cords on equipment on the other hand masks the problems further and invalidates their results.
The rub is that components and designs have differing susceptibilities and emissions. The best place to control both is during the design phase of the component and at that component's interface to the outside world. If there's not enough data available for that, then what's the chance a consumer will do better? Like you say, it's trial and error.
It may sound cynical but I was in Best Buy a couple of year ago and based upon the prominence and prices of the power conditioners, I think that's where they make their money along with service contracts. They are both post-resistance sales that prey on insecurities.
Regards, Rick
Hi.
Comments:-
(1)Many, if not all, audio electronics manufacturers QC test their products on filtered/conditioned power points on the bench. If the powerline at home is so fouled as to offset the tested performance of the gear, too bad.
(2) I tested the powerline noises of my home, my audio friends home & an electronic retail store with a brandname powerline & EMI noise wideband analyser. I can definitely read up noise voltage riding the AC powerline voltage.
I can even detect radio broadcasts coming out from our home powerlines via the monitor speaker built in the noise analyser!
c-J
Hi,
Thanks for your comments.
Noise is always an issue with power systems. The nature of the noise on the grid has changed over the years largely due to capacitor input power supplies and now switchers. At issue is how to convince the manufacturers to address the problem rather than regarding it as somehow the fault of the user.
As your own tests demonstrate, the real world power input often isn't pretty...
Rick
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