[Kevin Haskins]

Interesting reading here! So is it likely that power conditioners (not voltage regulators) are just a gimmick, or is it important to filter out the high frequency noise on an AC line? Does the high frequency noise (when present) actually impair audio performance in a measurable (objective) manner?

P.S. I believe Musical Fidelity brags about choke-regulation on several of their products...

Wish it was that easy.   It might.... depends on the situation.   If you have RFI ingress into the chassis you can have an op amp  oscillate.   In that  case you may have audible levels of distortion.   Or.... it may cause no problem at all and do nothing audible.

It depends on too many variables to give you an easy answer.   Good engineers will design equipment to minimize the RFI that gets into our out of the chassis as part of good design practice.   

[Vinnie R.]

Does the high frequency noise (when present) actually impair audio performance in a measurable (objective) manner?

Hi NewBuyer,

Well if the power supply section of an audio component (e.g. amplifier) does not remove the high frequency noise, that noise will be present on the DC voltage rail(s).  The input signal of an amplifier modulates the amplifier's DC voltage rails (an amplifier does not make the input signal bigger....it uses the input signal as a "template" for making a new signal that is supposed to be a copy of the input, but a larger one.  Aside from being larger, the variance of the output compared to the input is distortion).

In the case of the amplfier, if the noise passes through its power supply, it ends up on the DC rails, which is what the speaker outputs are actually made from.... so YES, it ends up on the signal going to your speakers. 

In the case of a source (e.g. CDP)...same idea, but now that low-level output signal (with the noise on it...if it's power supply doesn't remove it) goes to an amplifier and ends up getting amplified, and so does the noise!

IMHO, a good power conditioner DOES make a difference (improvement!) in a system.  I've heard it many times... clean power results in less grain to the sound, less backgound noise, cleaner imaging, etc.  You can also measure the rails on a scope, before and after using a power conditioner.

Also, some power supplies in components actually ADD noise in the AC to DC conversion process.  A good example is a switch mode power supply.  They can even add noise back onto the AC line.  They also can radiate noise (RFI) that a nearby component can pick up (such as a AM/FM Tuner).  You don't even need to measure it to know it is there... you'll easily hear the interference. 

So much can be written about this subject.  I just wanted to pass on some background on why clean power is important. 

Best regards,

Vinnie

[NewBuyer]

Thanks to both of you - this is all very informative. In addition to amps, do any of you feel that high-frequency AC noise might also impact/degrade digital gear performance, such as a DAC or clock chip?

[Kevin Haskins]

Thanks to both of you - this is all very informative. In addition to amps, do any of you feel that high-frequency AC noise might also impact/degrade digital gear performance, such as a DAC or clock chip?

RFI at the levels you to pick up from airborne and radiated transmission is extremely low in comparison to the output signal level of the main power supply rails.   Also... there is a transformer in the way... big inductor that makes a high pass filter.    The only way it can get transferred via conducted methods is via the ground to the chassis and via capacitive coupling between the primary & secondary of the transformer.     Where it becomes a problem is the wire run from the IEC input to the power switch & primary of the transformer.  Over that length is will re-radiate throughout the chassis.    It does so at low levels relative to the actual signal and at the frequencies we are talking about, even if your loudspeaker where capable of playing these frequencies (it isn't) would be swamped by the program material.   

Where it is a problem is how it interacts with the circuit design of the amplifier/preamplifier or digital source (CD player, DAC etc...).   Most op amps are much wider bandwidth than just needed for audio.   Many can be caused to go crazy (oscillate) when fed the right (or should I say wrong) input signal.   That is where RFI is a problem.  Not directly but indirectly.   By causing the op amps in the signal path to oscillate you cause the distortion levels in the program material to skyrocket in unpredictable ways.   That would apply to a DAC or other digital source as well as amplifier or preamplifier. 

Ironically valve based gear is probably much more immune to the effects than are modern wide-bandwidth integrated circuits.   

[Rob Babcock]

Personally, the only use I have for AC power anymore is as a convenient means for charging batteries. 
se

I'm in the same boat as you, SE  aa

That's all well and good, but tell me- how many batteries & how big will they need to be to keep my pair of Hsu subs running at Dolby Reference levels all the way thru Lord of the Rings!

[NewBuyer]

As I shop for power delivery/conditioning units, I remembered this interesting thread.

It seems that the main benefit from power conditioners may be from lessening RFI, and more specifically, those RFI frequencies that apparently can cause op-amps to oscillate (I'm gathering this from previous posts in this thread).

Am I restating this accurately? If so, what frequencies are we realistically talking about here - are these frequencies up in the MHz range?

It is interesting to me that the power supplies in our equipment wouldn't filter-out conducted EMI/RFI already during the AC/DC conversion. I've occasionally read that an audio designer would have to be astonishingly poor at designing their equipment and power supply, if a separate input AC conditioner was actually needed to make it perform at the top level it was designed for. Is that correct?

Perhaps instead of looking for a great power conditioner, should I really be avoiding any equipment makers whose products would ever need such a conditioner?

[Occam]

It seems that the main benefit from power conditioners may be from lessening RFI, and more specifically, those RFI frequencies that apparently can cause op-amps to oscillate (I'm gathering this from previous posts in this thread).

Wayne's supposition as to the susceptibility of opamps (either monolithic or discrete) might well be correct (feedback network senior moments?), but you'll find radically different topologies similarly benefit from adequate power conditioning. Those benefits in a 'darling' or 'Baby Sofia' SET tube amp can be just as large, if not larger.

Perhaps instead of looking for a great power conditioner, should I really be avoiding any equipment makers whose products would ever need such a conditioner?

So after you buy that CAT preamp, whaddaya gonna do? Give it 3 years, and some vendors will realize power conditioning is best implemented in the component itself because the load conditions are specifically known.  Or possibly vendors are correct in that customers, overall, are frankly unwilling to pay that incremental cost, and those consumers that actually build systems for sound quality will understand their need for external conditioning, even accepting the fact that it may be non optimal and/or costly.

We could palaver endlessly. Audition a PS Audio Duet with a return privilege. I'm not saying its the best out there, just the best, IMO, bang for the buck commercial product that I'm aware of. But metrics do vary as does each system's optimal allocation of resources.
http://www.google.com/search?num=100&hl=en&rls=GGLR,GGLR:2006-06,GGLR:en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=ps+audio+duet&spell=1

[NewBuyer]

...Give it 3 years, and some vendors will realize power conditioning is best implemented in the component itself because the load conditions are specifically known.  Or possibly vendors are correct in that customers, overall, are frankly unwilling to pay that incremental cost...

This is so interesting! So then, much of our hifi gear potentially could have had "proper" power supplies that address the specific needs of the component, but the designers are specifically choosing not to do it - even though such a decision certainly hampers the very gear they are designing. Thus also requiring the unsuspecting customer to need to purchase yet another component, a power conditioner - all since the designer wasn't willing/able to just put a proper power supply in there, in the first place. Why does this happen - is it all due to cost-cutting?

[ctviggen]

We could palaver endlessly. Audition a PS Audio Duet with a return privilege. I'm not saying its the best out there, just the best, IMO, bang for the buck commercial product that I'm aware of. But metrics do vary as does each system's optimal allocation of resources.
http://www.google.com/search?num=100&hl=en&rls=GGLR,GGLR:2006-06,GGLR:en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=ps+audio+duet&spell=1

Thanks for that info, Paul.  Oh yeah, and I didn't mean "palaver", either! 

[Occam]

NewBuyer,

I'm certainly not suggesting any conspiracy on the part of manufacturers to give less than their best efforts for the money. While I personally believe conditioning is best implemented internally, the counter argument that it is best left external via a dedicated powerconditioner has merit. As conditioning is often bundled with ancillary functions, spike/surge protection, over/under voltage protection and power on/off sequencing, it could certainly be argued that those functions should be centralized.
Regardless, as power quality has declined substantially over time (this is not the fault of audio manufacturers), and if you feel this effects your audio and/or video experience negatively, you have 3 choices -

1. Do nothing and whinge.
2. Buy only those components that have adequate powerconditioning built in, AND ALSO meet your other subjective and objective needs. Good luck with that.... The only component that presently meet those characteristics for me is the CAT preamp.
3. Spend/build/steal whatever external conditioning you feel is justified by your own cost/benefit analysis. Ideally, this should involve actually hearing whatever in your own system, rather than deciding based on internet truthiness.

FWIW,
Paul

[Carlman]

I was a long-time non-believer in power conditioning and power cords until I finally heard a black and white difference while comparing various forms of both in my system.

My system (and room) needed to be up to the task to really hear the differences.  (Positioning speakers to within a mm of each other, dedicated power, lots of room treatments, experimentation, measurements, etc.) 

The things I'd tried in the past (in my system) were mostly DIY and cheap stuff.  Once I tried Black Sand Cables, I was pretty shocked at how much difference a power cord could make.  Once I tried a Ridge Springs Audio power conditioner, I was floored at how good things got.  I went to a friend's house and repeated what I'd heard at home with the RSA Haley and BSC cables... he bought one on the spot, no questions asked.

So, all I know is until you experience what good power conditioning and cabling can do, you won't get it... I didn't.  If Paul says the PS Audio Duet is good, I'd go for it.  If you want something a bit nicer, I'd suggest the RSA Halley.  I haven't compared the BPT directly to anything but I've heard the BPT in others' systems... and I didn't really like what I (think) it did in those systems.  If I get another chance to compare a BPT to an RSA I'll do it...   

-C

[ctviggen]

I've had multiple different power cords, cryogenically frozen outlets, used the "capacitors between hot and neutral" trick, and I'll be darned if I can tell any difference.  Having said that, I use fancier power cords for all of my gear.  And, my system is located a scant few feet from my fuse box.  Further, my system isn't set up for back-to-back testing of power cords and the like.  Consequently, it's very hard for me to do comparisons of power cords.  My mind isn't good enough to remember what something sounds like.  (Except when installing bass traps -- then it was easy to hear the difference.) 

[ctviggen]

Oh yeah, and I'll probably buy the PS Audio Duet.  It's not too expensive and seems to allow me to run my entire system off of it.

[Carlman]

FYI, This thread went a little astray from the original topic so I split into this new one:
http://www.audiocircle.com/index.php?topic=35411.0
-C

[NewBuyer]

[I'm copying these questions into this thread, from the other split-off thread, at Marbles' suggestion.]

It was mentioned earlier, that RFI is in fact blocked by the equipment transformers, but the line run from power-cord input to transformer might still radiate RFI into the chassis/internals and cause problems, specifically, could cause op-amp oscillation.

Is RFI the major culprit then, that conditioners aim to reduce? If so, why not just put a R/C, or a ferrite, on the line run in question, or even on the power cord, and eliminate the costly conditioner units?

What are the noise frequencies that we are worrying about here (regarding op-amp oscillation risk, etc) - are they in the MHz ranges, or are they down in the kHz ranges?

Thanks for reading my questions and helping me understand this all better...

[slbender]

Well I'd say, that cost cutting has always been a part of any product, except stuff up beyond the Mega-buck range.  And while they exist, just who buys these $90,000 Turntables, and $10,000 Cartridges, to go with their $40,000 Preamps, and $125,000 SET Power Amps and $100,000 speakers ???  Obviously... people with too much money, and not too much sense.  But back here on earth, people who work for a buck, the old vintage equipment which was tubes, and minimalist, and simple, often worked great.  And all the power conditioners and filters you could lift, while it probably would do no harm, probably would also do no good.

In fact, at a recent meeting of Audio Syndrome Society, at the end of September, 2006 on a very highly regarded biamped system which used the: VPI Scout TT/Grado Ref Sonata, Sony SACD/DVD transport, Theta Pro Gen II DAC, Van Alstine T8 preamp, Behringer 8024 Dig Eq, heavily modified Heathkit W7m amps (EL34 push pull, rebuilt w/new PS by Paul Schwartz) on the Martin Logan ReQuest Electrostatic Panel speakers, and a Bryston 4B amp on the woofers, with a M&K MX 125- dual 12in subwoofer... the introduction of a power conditioner, made the system worse sounding  ...

I think it was placed on the subwoofer amp, and I seem to recall that it was a Custom Power Cord Company unit, one of the pricier units, but I wasn't really paying attention to what they were doing until they removed it.

So adding in power conditioning one can introduce non-complementary imperfections into an highly perfect system. I almost always use very minimalist equipment, most of which has been designed or rebuilt by myself.  In these cases of my stuff, so far, the use of power filters or whatever, has NO EFFECT on the sound, but at least it doesn't hurt (or just maybe my rebuilt stuff is built properly, and not MBA'd down to pitiful and a price-point).

In addition, in many modern units, the complex circuitry chosen by many makers of Audio Equipment, no matter what you do with power conditioners, only the slightest differences are heard.  And the sound is  pretty much a given, but due to the highly complex and expensive circuitry, it is merely designed to give better readings on a distortion meter, but it quite literally fails the test of sounding like live music.


-Steven L. Bender, Designer of Vintage Audio Equipment

...Give it 3 years, and some vendors will realize power conditioning is best implemented in the component itself because the load conditions are specifically known.  Or possibly vendors are correct in that customers, overall, are frankly unwilling to pay that incremental cost...

This is so interesting! So then, much of our hifi gear potentially could have had "proper" power supplies that address the specific needs of the component, but the designers are specifically choosing not to do it - even though such a decision certainly hampers the very gear they are designing. Thus also requiring the unsuspecting customer to need to purchase yet another component, a power conditioner - all since the designer wasn't willing/able to just put a proper power supply in there, in the first place. Why does this happen - is it all due to cost-cutting?

[Occam]

...
But back here on earth, people who work for a buck, the old vintage equipment which was tubes, and minimalist, and simple, often worked great.  And all the power conditioners and filters you could lift, while it probably would do no harm, probably would also do no good.

In fact, at a recent meeting of Audio Syndrome Society, at the end of September, 2006 on a very highly regarded biamped system which used the: VPI Scout TT/Grado Ref Sonata, Sony SACD/DVD transport, Theta Pro Gen II DAC, Van Alstine T8 preamp, Behringer 8024 Dig Eq, heavily modified Heathkit W7m amps (EL34 push pull, rebuilt w/new PS by Paul Schwartz) on the Martin Logan ReQuest Electrostatic Panel speakers, and a Bryston 4B amp on the woofers, with a M&K MX 125- dual 12in subwoofer... the introduction of a power conditioner, made the system worse sounding  ...

I think it was placed on the subwoofer amp, and I seem to recall that it was a Custom Power Cord Company unit, one of the pricier units, but I wasn't really paying attention to what they were doing until they removed it....

Steven,

Thanks for your impressions and welcome to AudioCircle. I'm certainly not disputing your conclusions as to what you heard. But I'm not familiar with this Custom Power Cord Company powerconditioner, nor have I found the price allways correlates with efficacy. I don't know its topology, specifications or implementation.
I can only speak to what I've personally experienced. With regards to 'old school' tube equipment, I've heard a 'Baby Sofia' SET integrated tube amp powered by my own Felicia diy conditioner at a NY Rave, and Gary Bauer's lovely rebuilt Citation II powered via a Audience Adept at another Rave. These components should qualify as 'old school' type tube implementations. In both instances, the universal consensus (mass hysteria) was that these components benefitted tremendously from the inclusion of specific power conditioning. But please note that the only power conditioners I vouchsafe are the Audience Adept, PS Audio Duet/Quintet, my own DIY efforts, Equitech, and (on faith in certain fellow posters) the Running Springs Audio conditioners. Obviously, your own electrical mains can make a substantial difference. In my Park Slope home, with minimal residential density and no nearby commercial consumption (for Brooklyn ), my power is rather good; far better than in a a friend's highrise condo a 1/2 mile away. Your own results in Queens would depend on similar considerations.

All I can suggest is that might reconsider your conclusions if you could audition a 'proper' conditioner.  Maybe not. As you're in Queens and I'm in Brooklyn, I'll PM you.

Regards,
Paul

PS  - Consider joining the NY Audio Rave
http://www.audiocircle.com/index.php?board=62.0

[PaulFolbrecht]

Time for my $.02.

My direct experience has told me that power cords can make a large difference in digital sources.  Before I understood the concepts at all, I'd have thought this was the least likely area for improvement, but that's not the case.  I've got a new house with good wiring and clean power, and conditioning is not needed (likely to do more harm than good - conditioning is a completely different category from power cords), but a good cord on my CDP drops the noise floor and pretty much makes *everything* sound better.

My problems with "objectionsists" are twofold.  The first part is the gross naivety - the assumption that parameters that can be readily measured are simply the *only* factors that could possibly affect sound.  That is simple naivety.  The second issue follows: the over-reliance on theory vs. actual experience.  Anyone who has never heard a readily audible difference provided by a good power cord simply has either narrow experience or can't hear as well as an average indiviual off the street.  It's about that simple.  Frequently, these are not subtle differences at all.

Oh, although I did just order some VH Audio products, my most expensive PC to date is under $100.  A cord doesn't have to be pricey to be good!

[tvyankee]

Hey Paul

Don't forget the test we did at my place with the BPT 2.5sig and the Nuforce AMPS.

Krusty

[Occam]

Dave,

Certainly, the NuForce line DEMANDS good powerconditioning to even qualify as listenable, and your BPT certainly came through. But the NuForces can hardly be described a 'old school' tube products. 
I didn't mention the BPT as I never got to hear what it provided to tube components with and without conditioning in a controlled environment. Sorry for the omission, and consider it added to the 'vouchsafed'.

Regards,
Paul