 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
62.49.5.176
I am not sure if the is the right forum for this question but,
What is the opinion of this forum of mains conditioners? Do the make a difference? If so what does that say of the internal power supply? And again if so- is there any hard research into rf noise break through in the power supply?
Follow Ups:
I think you really nailed it. If they do work, what does that say about the power supply?
Many power supplies are unregulated, they use a step down transformer, diodes and a few filter caps. More sophisticated supplies have regulators. Regulated supplies have filters (capacitors) after the regulators. Obviously the regulator should filter to a voltage, thus removing any external variation, and the additional caps should better filter.
Unfortunately we do not live in a perfect world. Caps have ranges within which they work, best at the center of the band. They generally do not filter out everything. Regulator help, but they too pass very high frequency grung which often muddies the mids. They are better than nothing, but they are not a complete solution.
That means that external filtering CAN help, but it does not mean it will. That would depend upon a lot of different factors. I tend to go for cleaning up the power supply. I generally begin with Fairchild Stealth Diodes. Then I use either .1 or .01uF Teflon or RT Rel Cap Styrene by-pass caps. Teflon is best, but a .01uF cap can cost as much as $40 + dollars. I will often replace stock caps with Black Gates, Nichicon Muse, Elna Silmics (sp?), or Panasonic FC's.
That will generally clean up your DC. Tefon rules, but RT's are a best buy, and do come close.
Best Regards,Lou
(nt)
The hum from AC-powered filaments of directly heated triodes or pentodes is benign if AC is purely sinusoidal. Unfortunately, with today's proliferation of capacitor input supplies and switching supplies power waveform is far from sinusoidal, which turns benign hum into annoying buzz. A conditioner that restores sinusoidal waveform is not just really helpful, it is a must with a DHT amp.
It is also important what is downstream of power conditioners. It makes little sense in conditioning power if one's equipment is a source of contamination. AFAIK, almost all commercial equipment uses power supplies that make noise. I haven't seen any that use "clean" choke input filters.
You are definitely right, replace those big electrolytic capacitors with some nice copper chokes and polypropylene film capacitors and the world is a much nicer place. The real "magic" of old tube gear isn't actually in the tubes, but the topology.
Hi.
But I tend to disagree that audio amps without the "clean choke input filers" bound to sound noisy.
c-J
There is solid engineering behind the advantages of choke input supply. Critical value choke preserves the sinusoidal waveform of transformer current, whereas capacitor input badly distorts it, creating high frequency noise. That is, exactly the noise that power conditioner is meant to alleviate.
One who uses power conditioner to feed equipment with swithing or cap input supply is like marquis De Sad who used to hand pick the most beautiful rose only to crush it into durt.
As to amps with inferior power supplies, they indeed don't sound noisy, they sound crappy.
Hi.
Let's check up the "Dynamic behaviour of PSU" report posted only yesterday in Tube DIY forum. An good ready-made technical reference.
Now take a close look at the the chart showing wave patterns of a choke of critical inductance 5H (page 3) vs that of a conventional C I/P PSU (page 5).
Regarding the obvious different voltage levels, the dynamic behavour of both PSUs as shown in their wave patterns were very similar, if not so deceivingly identical.
Ironically, they are both so dissimilar to the same choke I/P PSU using mercury vapour rectifiers.
IMO, the waveform pattern of the C I/P PSU is grossly smoother from attack to decay than the choke I/P PSU.
You want to comment on the report finding?
While sonics is so subjective, I am not in a postion to debate with you which type of I/P PSU should sound better to whoever.
Sorry, I don't find a adequate designed/built capacitor I/P PSU would sound "crappy".
c-J
It may be true that the downstream waveform is not different between the two, but what happens is that with a capacitor input power supply, the charging currents through the power transformer to charge that input cap are much greater. This causes the power transformer to radiate RFI like an antenna into the rest of the circuits of the amp. I think Allen Wright once said that by not implementing a choke input for your power supply, "that it is like hitting yourself in the head with a hammer."
If you do need the output voltage and therefore must implementa a capacitor input, use the smallest capacitor possible to deliver the voltage that you need.
Retsel
.
Just depends on the system and the person listening to determine if the difference is better or worse.
So Everything works just depends of who you ask.
.........but IME, unless one converts to balanced power or implements a true AC regeneration unit, then passive power conditioners, whether of the series or parallel discipline, will be more or less a crap shoot depending on the quality of ones AC to begin with and the quality of the power supply in ones components.
However, there are some very good passive units out there such as the Shunyata, Audience or the Walker units that consistently provide real world benefits when implemented. There is also the Hammond chokes which have garnered quite a reputation around here as providing consistent benefits as well but I have not ventured down that path prefering balanced power and the benefits it consistently provides over unbalanced AC and true AC regeneration which cannot be bested by any unbalanced power conditioner but they are quite spendy.
Then there is the aspect of AC outlet/plug quality and how that plays into the overall picture. Many of us have found that "audio grade" AC outlets/plugs, such as those from Oyaide and Furutech, provide real and repeatable benefits due to superior construction using ultru pure metals and outlet/plug bodies specifically designed to mitigate resonances.
I've included a link that explains the benefits of balanced power if anyone is interested.
Cheers,
~kenster
the transformer itself performs noise reduction regardless of whether the center tap or the neutral tap of the secondary are the grounded terminals.
Has there been a direct comparison of these two configurations with the same transformer?
Also, do you modify your audio components to fuse what was the neutral wire?
Hi.
My sonic experience with isolation tranformer is not than impressed.
So I have gone without for years, & taken the compromise of using in-line RF common-mode powerline filters instead.
To utilize the balance load theory, yet without using the sound impairing isolation tranformer, I've taped out 240V off the 120v-0-120V
grid transformer I/P provided in the breaker panel to power the dedicated powerline for the analogue equipment switcheable to 240V.
So I enjoy the noise cancelling effect of balance power without the pain of sonic compromise caused by any powerline isolation transformers.
c-J
As I understand it, for balanced power to be effective the plus and minus have to be very closely matched, ie, the windings have to be very carefully matched.
Any idea how closely the windings coming off the pole are matched?
Hi.
I've not monitored constantly the variance (if any) across the grid posts. But from random voltage checking of both live-pole-to-neutrals, my DVM does not show noticeable decimal volt discripancy at the wall outlets.
Yes, there is always some inevitable minor variance, primarily due to the common industrial way of winding the transformers rendering 100% twin like balanced winding impossible.
But, the major chunk of the noisy reactive or unconsumed portion of the AC power across the non-linear load will be cancelled out due to common mode rejection (or in simple language - out-of-phase cancellation in the transformer windings). So what left behind uncancelled dirty reactive currents that eventually pass into the common grounding circuit will be of much much smaller magnitude & much less harm could be done.
c-J
"Has there been a direct comparison of these two configurations with the same transformer?"R U asking whether a balanced transformer vs. a similar unbalanced transformer with the same current capacity has been compared?
Let me answer that question this way: balanced vs. unbalanced transformers performance, with regards to AC current/voltage transmission and immunity to noise, is a no brainer in my book if one understands the benefits of balanced power, let alone the fact that a balanced transformer presents the load with a much lower source impedence than an unbalanced line which results in a much more efficient transfer of potential energy to the load.
"Also, do you modify your audio components to fuse what was the neutral wire?"
I know this apect of balanced power has been discussed with great ferver in the past and no I do not implement additional fuses on the neutral line as the balanced power units I utilize have sufficient protection built in before the balanced transformer with the CinePro unit utilizing a GFI outlet in the first of the series connected outlets.
Also, the "theory" of balanced power I speak of is real and one only needs to implement a balanced power unit in ones system to understand/appreciate the benefits of balanced power.
Just because we as a public have been utilizing unbalanced power for the last ~100 years does NOT mean it is the end all/be all of the electrical energy supply. The unbalanced system is good but there are better ways to deliver noise free/low impedence power to ones system.
In addition, do we want to talk about the vast superiority of true AC regeneration or are we just keeping it to transformers?Cheers
You seem to be confused about the source impedance. Any transformer has loss mechanisms: eddy currents in the core and winding resistance. These will appear as additional source impedance if the setup is compared to the case with no transformer. Otherwise, you would have a perpetual motion machine!
The advantage of balanced power is that it balances the leakage currents into and out of the AC safety-earth, to which the chassis is usually tied.
Transformers also have limited bandwidth, and present a resistance to the AC line for high-frequency noise without passing the noise along to the load. This may provide a large benefit in some circumstances. This is why I asked if you had compared the balanced versus unbalanced configurations using the same transformer. The reduction of AC line noise should be similar in either case.
I'm not discussing regenerators at this point. I think regenerators have the possibility of creating additional AC line noise due to their power supplies.
"Transformers also have limited bandwidth, and present a resistance to the AC line for high-frequency noise without passing the noise along to the load. This may provide a large benefit in some circumstances. This is why I asked if you had compared the balanced versus unbalanced configurations using the same transformer. The reduction of AC line noise should be similar in either case."
Correct me if I'm wrong but an unbalanced isolation transformer cannot address Differential mode or Transverse mode noise. Common mode noise is addressed by both but an unbalanced transformer noise reduction is on the order of ~30db's. With a high quality balanced transformer, the noise reduction for the 3 aforementioned modes run from 42db to 62db to 84db respectively measured from 1Hz to 100Mhz.
One also has the advantage of zero noise/hum being induced into other nearby/adjacent power cords and IC's because of the power conductors used for feeding components are of equal and opposite voltages that cancel each other out. Of course, one must carefully route the balanced transformer input supply power cord :-)
There is also the advantage of the energy stored in the transformer which acts like an AC storage battery and will "stiffen" the transformers output during sudden transient demands from say an amplifier/subwoofer.
It would be interesting to compare an unbalanced isolation transformer with a balanced transformer of the same output current capacity in the same system.
Cheers
The primary winding has some stray capacitance. This will interact with the inductance to create a resonant circuit. Above resonance, the primary winding impedance drops as frequency increases. The primary winding is typically made of solid wire, so it will have a resistance that increases with frequency due to skin effect.
The net result of this is increased losses for high frequency noise. The transformer core also has a cut-off frequency due to magnetic domain switching limitations. This blocks the transfer of high frequency noise, so the only remaining path is the capacitance between the primary and secondary windings. A properly-designed transformer has an electrostatic shield between these windings to reduce the capacitive coupling.
I don't see how a balanced configuration makes any of this work better. If a balanced design rejected normal mode noise, it would also reject the 60 Hz power frequency.
Magnetic energy stored in the core is energy not delivered to the load. It is not a reservoir available for peak demands.
<>
Induction is due to current, not voltage. In either balanced or unbalanced, the current would "cancel out".
Balanced is not about equal voltages. It is about equal impedance to ground.
Not disagreeing about balanced power being a plus, but how in the world do you justify "the fact that a balanced transformer presents the load with a much lower source impedence than an unbalanced line which results in a much more efficient transfer of potential energy to the load."
The issue here has to do with ohms law and that is that the longer the wiring path from the breaker box to the outlet, the intrinsic impedence will add up thus lowering the power transfer ratio.
In other words, with a balanced transformer, one is drawing right off of the source with very little power loss since the load is connected mere inches from the power source.
Cheers
And what about the impedance of the transformer windings??
Don't they count?
I have been playing around with various power conditioners. But I think power factor correction is the way to go. Balanced and other technologies reduce noise, but they are going to impair the dynamics a bit. I consider my Blue Circel MR1200 balanced power conditioner in terms of dynamics to be 95-98% of directly going to the wall. (This number is bigger than other conditioners like Monster Power, the PS Audio unit added a tonal coloring). But I also bought a Furman Power Factor Pro which seems to give a 'boost' compared to going straight to the wall. I had this daisy chained ahead of the MR1200. But recently, I switched the amp (and subwoofer) to go into the Furman straight and all other components into MR1200. It sound s a little more 'strident' but I think this is the natural tone of the instruments.
Note, high end amplifiers come with a Power Factor correcting power supply.
IIRC, I seem to remember reading where the transformer impedence is on the order of .5 ohms for a high quality transformer.
I'll try to locate the article.
Cheers
You are correct. Any transformer has losses, and these will appear as additional source impedance in a setup compared to the case of no transformer.
Howdy
Balanced isn't a panacea, it has it's own problems in the real world. I agree that it might have been a better idea for some purposes, but there are lots of good ideas left on the side of the road in the interest of compatibility with the most common paradigm, e.g. any alternative to the qwerty keyboard :)
We've been over this before so I'll just bow out here.
-Ted
<>
120v is 120v. That is what equipment "expects". If equipment thinks, it would not know the difference between 120v balanced or 120v unbalanced. Thus, it would not be "bad news" either way.
The only problem would be if the equipment had its neutral input tied to ground. This would be either a design fault, or a really old piece of equipment. This is easily tested for.
It would be bad news if you didn't use a GFCI on the output of the balanced supply as required by code.
Howdy
Nope, the assumption is that for normal installations the safety ground level relative to the neutral is small. Besides what you mention this assumption can be taken advantage of in many ways. In fact I have some equipment that explicitly shuts down when the ground is too different than the neutral because it assumes some other equipment must have failed. This seems like the best design of all to me.
In the field of standalone appliances the world is much simpler, either a device is double insulated (in which case the safety ground is irrelevant) or the safety ground is there to ground out any currents left from a fault and hence is connected to the case.
But when you get to equipment which isn’t' standalone, e.g. all of our audio stuff that expects to be connected to other audio stuff, exactly how the safety ground is connected or not to the signal ground is very important. To complicate things further there are systems with switches that have options like ground lift, tie safety ground to signal ground directly, tie safety ground to signal ground thru (resistor, flash over tube, etc.)
The bottom line is that you need to contact your manufacturer for each piece of equipment in your system and ask about using balanced power to be safe.
I'll quit here. Some people obviously think balanced power is the best thing since sliced bread, some have had negative experience with it and some of us know enough about our equipment to take safety seriously.
-Ted
"I'll quit here. Some people obviously think balanced power is the best thing since sliced bread, some have had negative experience with it and some of us know enough about our equipment to take safety seriously"
I don't mean to sound like an ass Ted but just WTF does your statement imply? That some of us don't take electrical safety seriously or that some of us don't agree with your opinions?
Balanced power is no more dangerous than unbalanced power and anyone that thinks otherwise is just plain ignorant..............
Howdy
I'm sorry if my previous post came across as an insult. I tried to tone it down a little with the smiley :)
My post wasn't aimed directly at you and you left out of your quote my previous sentence "The bottom line is that you need to contact your manufacturer for each piece of equipment in your system and ask about using balanced power to be safe."
I stand by that and anyone who recommends to the contrary (i.e. that you don't need to check with your manufacturers) is indeed ignoring safety. When equipment is designed expecting a ground near the neutral except in error conditions providing anything other kind of power hookup needs to be checked out.
Note: I'm not saying that every device (or even most devices) don't work fine on balanced power. I'm saying that some don't and if you don't know for sure whether yours is designed in a way that's compatible with balanced power, don't use balanced power till you do know.
Here's an example of people taking balanced power too far, but at least he asked before he did something stupid: http://www.audioasylum.com/audio/tweaks/messages/134572.html
-Ted
P.S. Calling me ignorant is not only incorrect it isn't in the spirit of the forum. I know well of which I speak and when we don't agree we need to work on communicating with each other better not throwing around insults. Again I'm sorry if my previous post came across as an insult.
IMO, my retort to your condescending statement that I highlighted was well deserved/warranted although I made it a point to not directly point fingers.
Truth be known, I thought long and hard before even posting my thoughts and experiences with balanced power/AC regeneration due to the very fact of how this thread has degenerated into opposing opinions/misunderstandings and with regards to how it has been debated in past posts.
I agree that if there is a question as to whether a component is compatible with balanced power, it is the responsibility of the consumer to ensure said compatibilty/safety.
I still remain an hard core advocate of balanced power and the benefits it provides over the unlikely incompatibility issues that might arise.
Apology accepted and I extend a hand of apology as well.
Cheers,
~kenster
Only in very rare cases has using balanced power on equipment "expecting" to see unbalanced power has there been an issue.
I have not run into an issue of such in 7 years of using balanced power but that does not mean it doesn't happen :-)
Cheers
Everything was okay when I plugged into anything else, such as the Velocitor or IsoClean.
Howdy
Well I have more than one :)
As I've said before please check with your equipment manufacturers before using balanced power. It's just common sense.
-Ted
This is the first component in 12 years of Equitech usage that has not worked with balanced power.
It is a wireless remote controlled AC adapter designed to turn off/on whatever is plugged into it. I wanted to use it to remotely turn off/on my satellite receiver which I have confirmed spews out noise rather than manually plug/unplug it which is what I am back to.
Anyone have a fix for remotely turning off/on the sat receiver?
is it one of those x-10 home remote system?
x
Howdy
Whether they work or not depends on a lot of variables.
All equipment is built to some price point, that means of necessity that every part of it has some compromises including the power supply.
In my experience you get a lot more bang for the buck with dedicated circuits from your breaker box, upgraded outlets and medium level power cords than you do from most power conditioners out there. (But I have to say that I'm not afflicted by RF to the degree that some other inmates appear to be.)
Also every style of power conditioner is also built to a price point and has it's own compromises. One of the ones that is especially insidious in some is current limiting: it can take the life out of the music and often this isn't detected in a quick A/B. You might throw the baby out with the bath water with some power conditioners and wonder why you don't listen to your system like you used to.
-Ted
Hi.
would they also impair the sound or not is my main concern given my bad sonic experience with powerline isolation transformers.
c-J
a
NT
There are many forms of power conditioners available. My DIY filters have been successful in reducing the RF noise influence on my system: Wadia 861 driving Gilmore Raptor switching monoblocks driving Magnepan MG-20 speakers.
RF noise goes around the filters in component power supplies because the big filter caps have a lot of parasitic inductance, due to their size and the conductor lengths required to get the electricity to all of their working surfaces.
RF noise also enters through input and output ports. Magnepan speakers make good radio antennas, and many amps will have sonic degradation from the RF noise picked up by the speakers. This is because RF goes wherever the parasitic capacitances allow, and most amps are simply not designed to keep the port noise from getting to the active elements. RF noise mixes with the audio signal and produces spurious audio-band artifacts. The treble becomes hard and crisp, the midrange dry, and the bass wooly from these artifacts.
You can experiment without cost by simply listening critically, then unplugging local RF noise sources and listening again. Any appliance that contains a microcontroller is likely to have a switching power supply for it, and generate continuous RF noise on the AC and through the air. You have to unplug these appliances to make them quiet for the experiment.
I too was skeptical until I spoke with enough people about the higher end conditioners such as the Silver Circle Audio Pure Power units & the Isoclean transformer based units. I recently purchased a Pure Power 5.0 and the difference is notciceable. It tightened up the bottom end (which was already quite good) and it removed the grunge caused by a less than optimum electrical source. I had a fairly good electrical source as I have dedicated electrical circuits with their own grounding device, but as soon as I hooked up the Pure Power 5.0 I noticed the noise floor dropped. This resulted in more clarity and air around each instrument.
These units are not for the faint of heart as they aren't cheap and weigh close to 100 puunds depending on the model chosen. I chose Silver Circle Audio as it contains everything needed in a bundled package including 4 high-end outlets for connection of 8 devices and a high-end power cord to connect to the wall. Both the 3.0 and 5.0 models share this feature. After speaking with Silver Circle's president, Dave Standard, I understood the incremental build parts value of the 5.0 and it swung my decision to the 5.0, even though I don't have demending power requirements as my main electrical requirements is a Jadis integrated 60 WPC amp (DA88S) and a USB DAC for my computer audio server system.
With Isoclean, everything is 'a la carte' and can add up to a hefty price and not such a tidy footprint as you end up with boxes and cables all over the place.
The other selling point was Dave Standard, the owner of Silver Circle Audio. After spending 10 minutes on the phone with him I was convinced that this is a person that is passionate about what he's doing and it translates to his products. He also wanted me to follow up with him and let me know my impressions of the unit. Check out his website and you'll see what I mean (http://silvercircleaudio.com/).
Good luck.
One of the reason I am asking the question is there is massive argument going on in http://whathifi.com/forums/t/2040.aspx . This is rapidly going balistic. The are a few posters who are trowing physics as a reason as to why we don't need power conditioners. That all the filtering is done in the power supply as built in the hifi unit. This forum "Whathif" is not as technical aware as here so I am wondering if there is any research into rf break through with regard to the power supply. If it could be shown that not all power supplies are the same then any argument that claims that you imagined a difference becomes null and void.
I use a variac as a filter as I saw many Hifi demonstrators use them at a hifi show. I did notice a difference and I was blind tested on it (being disabled I can not get round the back of my hifi to see how it is plugged).
"The are a few posters who are trowing physics as a reason as to why we don't need power conditioners."
Poor science. Science explains observations and offers predictions. It doesn't guarantee that something will happen a particular way. If something doesn't happen as predicted then either the observations on which the prediction was based were wrong or incomplete, something else happened to intervene, or there's a flaw in the theory. With long established scientific theory usually you bet on the theory being right and the observations wrong but scientific theory usually isn't worked out in the context of sonic differences in an audio system. I've yet to come across any basic scientific theory affecting electronics which had listening tests in an audio system as part of the research behind it.
If you had a perfect power supply in each component you definitely wouldn't expect a difference. While some component power supplies are better than others and some are extremely good, perfection is not something we tend to come across here or anywhere. If it's less than perfect it can be improved upon and power conditioning may help. Whether or not it will help depends on the quality of the power supplies in your components and the quality of the conditioner. You need to suck it and see and then, if you think a particular conditioner does make an improvement, decide whether that improvement is worth the cost of the conditioner to you or whether you would be better off forgetting it or spending the money elsewhere.
Beware people who tell you that science says something can't make a difference. That's not a sound scientific approach. Likewise beware people who tell you that you can rely on your ears and ignore the science. That's simply stupidity. You need both science and your ears and we all sometimes make mistakes, whether about the science or about what our ears tell us.
David Aiken
Howdy
But I might argue with an (irrelevant to the current discussion) implication of one of your statements a little :)
Serious science including listening DBTs are often used in audio (hearing aids, MP3 and other perceptual coding development, etc.) and much more than people apparently think in company's proprietary tests of audio hardware or audio processing algorithms. I suspect that there are a lot of companies that know more than they let on about what they've learned by doing good research in audio. (I also know that there are a lot of companies flying by the seat of their pants.)
-Ted
I'll wholeheartedly agree with your points on hearing aids, digital codecs, and the like, and also on some audio companies using listening tests in their product development; but what I said was:
"I've yet to come across any basic scientific theory affecting electronics which had listening tests in an audio system as part of the research behind it."
Perhaps I should have said 'electricity' rather than electronics. You're talking applied practice in audio related areas and I was trying to talk electrical theory of the sort that gets used to argue whether or not a power filter makes a difference. I definitely didn't any implication of my statement to get in the way of the truth of a statement like yours about particular applications which rely on listening tests of necessity since what counts in those cases is what people actually hear.
David Aiken
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
