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Thoughts on power conditioners?

FrantzM

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I tend to think of a competently designed, generous power supply like a buffer or abstraction layer to the circuitry inside -- everything on the other side of the DC buss is a black box to the circuits inside. They only know about the juice from the power supply.
Same here ... I , however noticed back in my Orthodox Audiophile days improvement when AC was well taken care of. From that point I have taken care of my AC almost as a religious ritual. :)
 

DonH56

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Don has already provided an extensive answer - I'll just round it off by saying that the mains power needs to be as "perfect" as possible: zero distortion, zero impedance, zero noise riding on it is the ideal - and how you get that is the roads to Rome answer. Why is this needed? Because the powers supplies and filtering in most components are not good enough, and all the "defects" of the mains are adding to the low level noise/distortion soup in the final sound. Feed any reasonable playback rig absolutely pristine mains, and you're that much closer to optimum sound.

Sorry to be so late on this.

Given The Way Things Work, I would say rather that the component's power supply should as perfect as possible, including isolating it from whatever the mains (incoming AC lines) are doing. Based on my somewhat limited experience over many years with systems from audio to RF I think depending upon the incoming AC power to be clean is folly. With a halfway decent power supply, it doesn't need to be, and isolation cross the power supply is very, very good in the vast majority of components, at least the ones I have seen. Then it is up to the designer to provide adequate filtering and decoupling on the output side of the power supply to feed the electronics inside. Note filtering may include physical bulkheads and shields as well, and proper layout (of ground pours, power pours, and component orientation) is critical if you really want extremely low noise. Not that most audio components really need go to that extreme for the noise to be inaudible. Again IME/IMO.

Cost also enters into things, natch. Decoupling on the boards my company designs is extensive (yes, partly my design, for the HS analog stuff) and thus costly, but results in about 80 dB noise floor relative to the (1 V) power rail. A lot of the cost is due to very wideband (GHz+) decoupling that is not needed for audio circuits; if I limit myself to say 1 MHz then the noise floor is ~120 dB or better. Then add power supply rejection (PSRR) of the circuits themselves, which in the audio band can be another 80 - 120 dB, and it's hard to see power supply noise being much of a factor. IME, while some products due exhibit low-level hum (typically 120 Hz and multiples from a diode bridge of a linear supply), most of the noise is regular old Johnson (thermal), shot, and very LF noise (flicker, popcorn, etc.) generated within the circuits themselves rather than coupled from the power supply (let alone the AC mains).

What I have seen be more problematic is bad grounding; I wish every component had a nice heft chassis ground connection so I could ground them all appropriately and so as to limit any dependence upon the incoming power ground. Can be a challenge, alas, given things like cable and satellite TV feeds that bring in their own grounds, but those can be easily isolated so a nice star or other competent ground scheme can be implemented.

Finally, @fas42 may have made significant improvement in his old HT system, but to me that speaks to the poor quality of the power supply (probably due to cost constraints), not the quality of the AC line.

FWIWFM - Don
 

amirm

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I note this review, http://www.stereophile.com/content/...monoblock-power-amplifier#pII2jwxHKtVLC9GH.97. In which the reviewer noted some characteristics to the sound - I take it you wouldn't agree with them ...
Oh you are being kind. They ruthlessly rejected it as anything worthwhile!

Fortunately as subjective tests go, you can always shop for another one. :p This one http://www.theabsolutesound.com/articles/mark-levinson-no53-monoblock-power-amplifier-tas-213-1/

"Conclusion
The Mark Levinson Nº53 is an intriguing product that represents a new direction for this venerable company. As the company’s first switching amplifier and current flagship at $50k per pair, the Nº53 shatters the stereotype of the switching amplifier as the technology of sonic compromise. The Nº53 is a pivotal product for Mark Levinson, and one that says much about the brand and the company’s direction. The fact that it uses such a radically different topology is a daring move.

But it’s a move that has paid off, in my view. The Nº53 has some remarkable—even stunning—sonic qualities. These include dynamics, bass grip, midbass articulation and expression, and the ability to present music as separate instruments rather than as slightly homogenized. In these areas, the Nº53 was world-class.

The Nº53’s somewhat forward spatial perspective, slight emphasis on the upper-midrange and treble, and vivid soundstaging will suit some listeners more than others. If you lean toward the warm, forgiving, and rounded presentation of a single-ended triode amplifier, the Nº53 will likely not be your cup of tea. For those listeners who want to hear, with great precision and vivid clarity, every last detail on a recording, the Mark Levinson Nº53 will likely be a revelation."


Me? I don't put value on either review. I have another amplifier, this time all linear, Mark Levinson No 532 Reference:

Mark-Levinson-No532-Stereo-Amplifier-4-800x600.jpg


I don't use it because to my ear it doesn't do anything the 53 does with more efficiency and power.
 

Thomas savage

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Is there any reason why using balanced power might have a negative effect on a amplifiers performance?
This is the insides of the amps im running ...,

image.jpeg


I ask because I get strange 'shadowing' on the high frequencies when I use my balanced power tx.
 

DonH56

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Not sure what you mean by "shadowing" and I can't tell a lot about the amp from a picture of its guts.... Balanced power can cause some amplifiers to behave strangely due to the shift in ground reference. I have little experience outside the test bench, and not a lot even there, but I've measured higher noise, motor boating (LF cycles) and oscillation, and in the rare case the amplifier would not operate (blown fuse) when it assumed neutral and safety ground were at the same potential. I wonder if your amplifier is ringing badly or even oscillating at the top of the audio band or above and that is "tinting" or "smearing" the HF signals when they excite the oscillation. Have you asked the manufacturer?
 

Thomas savage

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Not sure what you mean by "shadowing" and I can't tell a lot about the amp from a picture of its guts.... Balanced power can cause some amplifiers to behave strangely due to the shift in ground reference. I have little experience outside the test bench, and not a lot even there, but I've measured higher noise, motor boating (LF cycles) and oscillation, and in the rare case the amplifier would not operate (blown fuse) when it assumed neutral and safety ground were at the same potential. I wonder if your amplifier is ringing badly or even oscillating at the top of the audio band or above and that is "tinting" or "smearing" the HF signals when they excite the oscillation. Have you asked the manufacturer?
Thanks, iv not contacted the manufacturer directly only the distributor.

On a frequency sweep the HF seem to carry something else with the signal ( ringing , tinting fits ) oscillation was my guess but I can't measure it. Also the bass is not as tight and defined..

It's perfectly fine on normal mains, better in that it avoids the above but seems to carry a little more noise too ( subjectively).

Thanks Don..
 

watchnerd

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Same here ... I , however noticed back in my Orthodox Audiophile days improvement when AC was well taken care of. From that point I have taken care of my AC almost as a religious ritual. :)

Effective, or just habit and ritual at this point?
 

fas42

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Since we're in show off mode, this is the insides of my model of Perreaux amp, used for the first dose of good sound 30 years ago:

1389685359-1086642669_n.jpg


It got the job done, but its power supply was a major weakness. Major modifications by me over the years, the insides look terrible - and I still have it ...
 

watchnerd

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I find these amp shots interesting. They're like looking at pictures of muscle cars from the 1970s.

My ICEPower mono blocks are so much smaller. And cooler.
 

fas42

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Cost also enters into things, natch. Decoupling on the boards my company designs is extensive (yes, partly my design, for the HS analog stuff) and thus costly, but results in about 80 dB noise floor relative to the (1 V) power rail. A lot of the cost is due to very wideband (GHz+) decoupling that is not needed for audio circuits; if I limit myself to say 1 MHz then the noise floor is ~120 dB or better.
I'm impressed !!
What I have seen be more problematic is bad grounding; I wish every component had a nice heft chassis ground connection so I could ground them all appropriately and so as to limit any dependence upon the incoming power ground. Can be a challenge, alas, given things like cable and satellite TV feeds that bring in their own grounds, but those can be easily isolated so a nice star or other competent ground scheme can be implemented.

Finally, @fas42 may have made significant improvement in his old HT system, but to me that speaks to the poor quality of the power supply (probably due to cost constraints), not the quality of the AC line.

FWIWFM - Don
I'm sure there is interdependence between grounding and quality of mains - I've chosen to focus on erecting the highest barrier between mains anomalies and the working circuitry, which means the filtering is placed anywhere in the chain from the outlet to the voltage rails inside the component - I've experimented with different techniques over the years.

The Philips HT did have a natural advantage - the supply had to to be able to drive 5 channels to reasonable levels, in raw form. Just using 2 meant there was more on tap, comparatively speaking - the mods allowed the unit to play at maximum gain, without notable problems; ear splitting sound levels were quite easy.
 

watchnerd

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So how important is all this power conditioning stuff in the big picture?

If I were to rank the impact of categories, I'd rank them:

1. Recording quality
2. Speakers
3. Room (almost a tie for #2, though)
[big gap]
4. Amps
5. DACs

Where would all these power issues fit in such a ranking?

Or make your own...
 

amirm

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Since we're in show off mode, this is the insides of my model of Perreaux amp, used for the first dose of good sound 30 years ago:

1389685359-1086642669_n.jpg


It got the job done, but its power supply was a major weakness. Major modifications by me over the years, the insides look terrible - and I still have it ...
Those TO-3 package transistors (array of 6 on each side) used to be the sign of amplifier manhood! Today they are so much more expensive than alternatives that are rarely used. I used to like them for hobby use since even without heatsink they can dissipate fair amount of power.
 

fas42

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Those are actually the "famous" Hitachi power MOSFETS of that era, that ended up being used in lots of PA amps and other gear where being driven hard was part of the deal. Their ability to get the job done was never in doubt, it was the power supply that was the Achilles Heel ...

http://www.perreaux.com/about/perreaux-history
 

fas42

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So how important is all this power conditioning stuff in the big picture?

If I were to rank the impact of categories, I'd rank them:

1. Recording quality
2. Speakers
3. Room (almost a tie for #2, though)
[big gap]
4. Amps
5. DACs

Where would all these power issues fit in such a ranking?

Or make your own...
My technique is orthogonal to just about everyone else - I start with the assumption that the system in front of me can deliver optimum, convincing sound. The fact that it doesn't is due to weaknesses, lackings, poorness of implementation, etc, etc - so I diagnose: where are the audible flaws, what do I hear wrong in the sound? What is that telling me?

So, with your list of "things", Speaker, Amps, DACs, Power supply are all equal - whichever has the biggest problems is that which needs to be tackled. Room and Recording quality are not in the list, because they automatically disappear as "something that needs to be worried about" when the other stuff is sorted.
 

fas42

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How effective is a bog standard isolation tx in terms of giving a clean mains output?
Thomas, I've explored this area with a DIY version, and it certainly helps. The audio friend down the road uses them on his Naim amps, and Quad CDP and it benefits him.
 

RayDunzl

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They're like looking at pictures of muscle cars from the 1970s.

Half of a Krell Master Reference Amplifier (monoblock) Output Channel board:

16020d1335552332-innmat-hva-du-vil-krell_pic6b.jpg


The Heat Sink would bolt on top of that.

Driver:

Krell6.GIF


Road Testing:

stereogear3_zpsc311def0.jpg
 

fas42

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Half of a Krell Master Reference Amplifier (monoblock) Output Channel board:

16020d1335552332-innmat-hva-du-vil-krell_pic6b.jpg


The Heat Sink would bolt on top of that.

Driver:

Krell6.GIF


Road Testing:

stereogear3_zpsc311def0.jpg
It wins ...
 

RayDunzl

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The 2 x 50W amplifier in my little JBLs - STA350BW:

upload_2016-12-27_17-55-33.png


Which didn't even get a comment in its thread.

I thought maybe it drove a couple of transistors on the board, but they seem to be part of the power supply instead.

So, all in a chip, no heat sink unless it uses the board itself.

But I get it, nothing to see here.
 
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