[woodsyi]

Paul,

I am not sure if this is the proper circle for the question.  Feel free to boot it to more appropriate place.  

I have been on a kick to find power conditioning for my amps.  In the process, I have come across many designs and brands that claim to do one thing or another.  So far some work on one instrument and not on others.  Some don't work at all for me.  You live in a suburb much like me where power grid can be over extended at times.  How would you rate the importance of these categories in power conditioning: voltage fluctuation, common mode noise and transverse mode noise?  Voltage fluctuations I can understand.  In real world what are the most common sources for the different types of noises and what method of conditioning is most suited to address each?  I am basically asking you to sort of give an overview of what we have to consider and deal with when we "condition our line."  Thanks.

[Levi]

I like Richard Gray products.

Also there are types of noise transmission...ex Radiation, electrostatic, Magnetic.

Most common source of electrical noise:
#Arcing
#Computer and TV systems
#Electrical Fences
#Switching systems
# ac power lines
# motors and motor starters
# transformers
# relays
# generators
# rotating and reciprocating machinery
# arc welders
# vibrators
# fluorescent lamps
# radio transmitters
# electrical storms
# soldering irons

Lots of stuffs to think about huh.

Paul,

I am not sure if this is the proper circle for the question.  Feel free to boot it to more appropriate place.  

I have been on a kick to find power conditioning for my amps.  In the process, I have come across many designs and brands that claim to do one thing or another.  So far some work on one instrument and not on others.  Some don't work at all for me.  You live in a suburb much like me where power grid can be over extended at times.  How would you rate the importance of these catego ...

[woodsyi]

# vibrators

How do these work in audio?  

[Levi]

Good question.  

That's why I let these guys do the reading.  

Suggested Additional Reading

    * Coffee, M.B., "Common-mode Rejection Techniques for Low-Level Data Acquisition." Instrumentation Technology 24, No. 7: 45-49 (1977).
       
    * Ficchi, R.F., Practical Design for Electromagnetic Compatibility . New York: Hayden Book Company, 1971.
       
    * Freynik, H.S., et. al., "Nickel-Chromium Strain Gages for Cryogenic Stress Analysis of Super-Conducting Structures in High Magnetic Fields." Proceedings of the Seventh Symposium on Engineering Problems of Fusion Research , October, 1977.
       
    * Hayt, W.H., Jr., Engineering Electromagnetics . New York: McGraw-Hill Book Company, 1967.
       
    * Klipec, B.E., "How to Avoid Noise Pickup on Wire and Cable." Instruments & Control Systems 50, No. 12: 27-30 (1977).
       
    * Krigman, Alan, " Sound and Fury: The Persistent Problem of Electrical Noise ." In-Tech 32, No. 1: 9-20 (1985). (Extensive bibliography).
       
    * McDermott, Jim, "EMI Shielding and Protective Components." EDN 24, No. 16: 165-176 (1979).
       
    * Morrison, Ralph, Grounding and Shielding Techniques in Instrumentation , 2nd Ed. New York: John Wiley & Sons, Inc., 1977.
       
    * Severinsen, J., "Gaskets that Block EMI." Machine Design 47, No. 19: 74-77 (1975).
       
    * Sitter, R.P., "RFI - What It Is and How to Control It, Part 11: Reduction of Interference." Instrumentation Technology 25, No. 10: 59-65 (1978).
       
    * Stein, Peter K., "Spurious Signals Generated in Strain Gages, Thermocouples and Leads." LF/MSE Publication No. 69 , April 1977.
       
    * Stein, Peter K., "The Response of Transducers to Their Environment, The Problem of Signal and Noise." LF/MSE Publication No. 17 , October 1969.
       
    * "Strain Gages Operate in 50 000-Gauss Magnetic Fields For Fusion Research." Epsilonics (published by Vishay Measurements Group, Inc.) 11, No. 3: 4 (1982).
       
    * White, D.R.J., Electromagnetic Interference and Compatibility , Vol. 3, Germantown, Maryland: Don White Consultants, 1973.

# vibrators

How do these work in audio?  

[woodsyi]

Good question.  

That's why I let these guys do the reading.  

Thanks for the information but that's a lot of reading.   Can somebody just give me a "Cliff Note" answer to my questions please?  

[TNT]

"I have been on a kick to find power conditioning for my amps."

Modern (and well designed) amps are pretty much immune to line noise and interruption, due to their power factor correction and SMPS.

At normal listening level, one can pull the power plug of a NuForce Reference9 in and out regularly yet nothing is changed or noticed in audio output.  Using a power conditioner could degrade its sound.  That was actually tried in A/B with precisely a Richard Gray power conditioner that costs more than a Ref9 so Mr. Richard Gray in person came and asked questions.  The answer is in the many levels of buffering and filtering of PFC+SMPS+DC caps etc...

[Levi]

I use Richard Gray Power Company products.   Almost all CES and HE shows used them in their demo rooms.  

Good question.  

That's why I let these guys do the reading.  

Thanks for the information but that's a lot of reading.   Can somebody just give me a "Cliff Note" answer to my questions please?  

[PhilNYC]

I use Richard Gray Power Company products.   Almost all CES and HE shows used them in their demo rooms.  

I would say this is mostly true for HT demos.  But at HE and particularly the most recent CES, Shunyata Hydra-8 and Audience adeptResponse were the most commonly used power conditioners...

[woodsyi]

Modern (and well designed) amps are pretty much immune to line noise and interruption, due to their power factor correction and SMPS.

I don't know how modern ASL push pull tube amp design is.  I am thinking steady voltage ( without choking off power) is crucial in tube amps.  One time my old Panamax unit flashed unsafe line voltage, which leads me to believe my input line voltage fluctuates.  The only time I had Felicia (balanced power) on my source, sound improved which, to me, says I have common mode crap on my system.  I don't exactly know what transverse mode noise is but I read of its existence somewhere.  I don't know if EMI and RF are separate issue or they fit in one of these.  I am hoping to get educated so I can ask more pertinent questions to those who sell conditioners.

[Levi]

Now it occured to me.  No wonder this room sounded awfull.

I use Richard Gray Power Company products.   Almost all CES and HE shows used them in their demo rooms.  

I would say this is mostly true for HT demos.  But at HE and particularly the most recent CES, Shunyata Hydra-8 and Audience adeptResponse were the most commonly used power conditioners...

[Occam]

......
Modern (and well designed) amps are pretty much immune to line noise and interruption, due to their power factor correction and SMPS.

At normal listening level, one can pull the power plug of a NuForce Reference9 in and out regularly yet nothing is changed or noticed in audio output.  Using a power conditioner could degrade its sound.  That was actually tried in A/B with precisely a Richard Gray power conditioner that costs more than Ref9 so Mr. Richard Gray in person came and asked questions. The answer is in the many levels of buffering and filtering of PFC+SMPS+DC caps etc ...

You're kidding, right?
Dunno from the Richard Gray stuff, but on the 2 occasions I've heard the(latest) Ref 8 from NuForce, I found them wretched without the mistrations of a BPT balancing conditioner. Then again, I wasn't overly impressed even after the grunge was wiped away.
You might well be in an environment where your power is pristine, but hereabouts in NYC, I think most folks would disagree with you, about everything you've said. It doen't matter whether on a well implemented linear or switching supply, they all benefit from the proper powerconditioning. Nor do I expect the vendor to address those issues within their component, as one's power environment is highly individual.

Woodsyi - From my perspective, transverse (differential) noise is the most difficult to deal with. Common mode noise is generally dealt with by power transformers and/or CMCs found in switching supplies. The use of X (accross the line) caps for powerconditioning is specifically to convert differential noise to common mode to be dealt with by inductive components. Other than that, the use of Y caps to specifically deal with differential noise has their own inherent problems in that they bleed that noise to ground and likewise dump current (leakage) onto the ground and rpotentially trip Ground fault interrupters. An advantage of transformer based balancing conditioners is that at output transverse noise is in the form of balanced differential noise, and shunting that noise via symmetrical Y caps tend to cancel those currents from those caps, much like inductive leakage to fed components, is 'cancelled' when powered by balanced power.

That being said, the topologically simple Audience Adept conditioner is truly impressive in its results. Its basically fronted by a delta cap arrangement, a single X cap and 2 Y caps followed by a CMC based filter  (with a separate CMC and terminating cap for each outlet), that yeilds very impressive results.

[woodsyi]

What about power regenerators?  Is the resulting power as clean as they claim?  I noticed that at least one unit uses Class D power module to regenerate power.  How does that effect the output?  PS Audio uses class AB and can be hot?

[TNT]

Occam> You're kidding, right?

Not at all.  Ref9 has much more filtering and buffering than Ref8, about 10X.

But it's good to know NYC has poor power quality, because of "discover a need and fill it".

Actually NYC people and large city dwellers have my sympathy.

[Occam]

...
Ref9 has much more filtering and buffering than Ref8, about 10X.

An order of magnitude in more filtering and buffering... Cool, but could you be more specific and elaborate? Measurements would be nice, as would a specific (or general) description of that circuitry that yeilds these improvements.

But it's good to know NYC has poor power quality, because of "discover a need and fill it".

Actually NYC people and large city dwellers have my sympathy.

Thats so nice of you. I and, no doubt, other urban dwellers will take note of your attitude.

[TNT]

Ref9 can accommodate any line voltage between 100 and 240Vac with its power factor corrector which provide a quasi-constant 400Vdc, with a reservoir capacitor storing energy at 400Vdc.  A DC-DC converter provides regulated DC at about 55V for its switching amplifier.  There's a total of 23,000uF of filter capacitor at 55V, plus huge common-mode and differential mode chokes.  Ref8 has about 2500uF of energy storage at 48V, or less than 1/10 (E = 0.5*C*V*V)

If one adds up all the noise attenuation, the figure would be at least 100dB @1kHz and higher with frequency by at least 4th order filter.

At typical listening level of 85dB with a 90dB sensitivity sepaker, the holdup time has been measured by AbeCollins and others on AA to be 10 seconds.  That means one can unplug and replug the power at a rate of one every 5 seconds, there will be no measurable of audible change in its audio output.

Keeping in mind that Ref9 senses the feedback from the speaker terminals, its PSRR of the amp alone exceeds 80dB @1kHz.

So the combination of PFC+SMPS+CMC+DMC+CAPS+Speaker feedback (with control loop gain-bandwidth > 500kHz) assures that some line noise don't get propagated to the speaker.

[Occam]

Woodsyi,

I don't have any personal experience with power regenerators in audio. These are, I assume, a retasking of designs from the likes of Elgar, Pacific Power, etc.... that have been used in lab environments for 30+ years. In audio, I believe there are 2 different approachs. The first is rectification of AC, and a total reconstruction of the AC waveform, via an oscillator and amplifier (analog or switching). An alternative are those 'filler-inners' (Elgar, Exactpower) which monitors the waveform and injects a signal to fill in any deviations from a pure sine wave.
Among the true regenerators (PSAudio, Accuphase...) I have heard stories of heat problems with some PSAudio A/B amp regenerators, but this is purely second hand.

Its interesting to note that a few vedors offer balanced regenerated power; PSAudio in some of their newer models, and ExactPower as an add-on balancing transformer. Balanced (technical) power is a separate form of powerconditioning, and while the transformers typically used to provide this also provide a large dollop of common mode waveform conditioning. the specific benefit of balancing is the cancellation of leakage currents in the fed component. IMO, this is 'icing on the cake' and the majority of the improvements stem from waveform and noise conditioning. This is illustrated by the Transcendant balancing conditioner whose transformer lacks shielding between primary and secondary, substantially compromising its noise filtering. IMO noise filtering is more important than those benefits provided by balancing. But my experience is by no means exhaustive, and there may be components whose leakage currents are large enough so that the balancing might take precedence.

FWIW,
Paul

[Levi]

Panamax 5500 series has this type of filtering technology.  I don't know if it works.  Every system is different, you just have to find one that works for you.  The Adept response is an excellent device but with a hefty price tag.  I would suggest you choose a budget and your priorities.  Then you can experiment which filter works with your system.

[woodsyi]

Thanks Pual for indulging me in this.  I am going to pester you with one more questions.  I have an electrician coming out to put this in Friday.  http://www.zerosurge.com/PDF/PM20_120b.pdf  I have the 240 version which is just two 120s side by side in a box.  Isn't there a way to wire it so that I will have balanced 120v on two 20 amp lines?  If I have all my audio on these circuits,  shouldn't I get some filtering aspects of balanced power and eliminate grounds loop?

[Occam]

Levi - If you read the Panamax description of their ACRegenerator(tm) you'll see it refers to the use of a transfromer, either configured for balanced or isolated (not in the medical power sense) power.
From their Max-5500-EX ad copy-

Power Cleaning and
Filtration with AC Regeneration
(True Isolation Transformer
Technology) with 4 amp capacity.

Its not regenerating power in the same sense that I referred to above, but hey, I'm not the vocabulary police, and they can use whatever terminology they please as long as they don't run afoul of the FTC.

Woodsyi - Putting in whole house surge protetion is an excellent idea. And the Zero-surge topology inherently provides some power filtration. But the only way you're going to get balanced power from your panel without an ancilliary transformer is 240vac, which in the States and Canada is inherently balanced. Split phase 240 is simply 2 antiphase 120vac lines. If you could rewire or switch all your components to 240vac, you could simply run a 240 line to your listening room. But because you'll no doubt be using your 120vac lines individually for non audio use, they will diverge from truly balanced and not be as clean as balanced power produced from a purpose built transformer.

[woodsyi]

So if I BRIBE a power company employee to install a dedicated transformer to chop power down to 60 vac coming in to my house, I can have balanced 120 vac circuits everywhere in the house?     I wonder what it will take........