Help diagnose the kind of power treatment needed

Hello Lew.

I would save your money for hardware. It's a pretty safe assumption that power at the wall is filthy.

I agree with Terry9. You can assume that there is noise coming from the outside, as well as noise generated by your components. If you use products like those made by, for example, Shunyata, you will be combating both. An isolation transformer connected to the wall outlet may not prevent your components from interacting in this way.

Terry,

Yes, I agree the assumption is safe. But I understand the reason some people prefer regeneration, others prefer filtration, others balanced transformers, etc is because the way in which the AC is filthy at different locations varies. I'm trying to determine in which way my power is filthy so I know what to look for as a solution.

Trying at home is not an option for me, or at least not a practical one. I can go ahead a buy something, but I would never know if that unit was the best I could have bought, and getting a second unit would take me about additional 6 months...

Personally I think all the options that are available all have their own shortcoming. With that said I like your idea of having someone (a professional) test and make a diagnoses regarding the problem.
I have no idea what type of equipment is needed or who does that type of work. I guess I'd start by phoning some good electricians in your area and see what their recommendations are. I know I'm not suggesting anything that you didn't already think of but I'm hopping you will keep us posted on this forum regarding your findings.

I understand the reason some people prefer regeneration, others prefer filtration, others balanced transformers, etc is because the way in which the AC is filthy at different locations varies.

And also because the sensitivity of different components to any given set of characteristics of AC noise and distortion will be different.

Unfortunately, IMO measurements of the AC noise and distortion characteristics are unlikely to be helpful, unless perhaps some unusually severe very specific issue is present. You may find the discussion between me and Mapman in this thread to be of interest. Some excerpts from my comments:

I suspect that in most cases even an oscilloscope would not provide useful information. While it would give a general idea of the overall magnitude of noise and distortion, it would say little or nothing about how the noise and distortion is distributed among what will inevitably be an enormous number of different frequencies. And there is no telling how a given component will react to a given noise or distortion spectrum. I doubt that even a sophisticated and expensive spectrum analyzer would be particularly helpful....

I think oscilloscope measurements would be unlikely to be useful because:

(a)The noise and distortion that is present on the AC will consist of a complex and probably time-varying mix of essentially ALL frequencies extending far up into the RF region, at many different amplitudes, including broadband noise as well as noise and distortion components at discrete frequencies..... There's no way to predict how a specific component in a specific system will react to that complex mix of differences.

(b)An oscilloscope won't provide much if any detail about that complex mix of differences anyway. It will pretty much just give an indication of the amplitude of the overall sum of everything, and perhaps also the amplitude of SOME of the discrete frequency components....

I learned many times over during my EE career that from a practical standpoint some things are inherently unpredictable, and can be determined only by trial and error. A good design will have as little sensitivity as possible to unpredictable variables, but no design is perfect....

Let's take the BrickWall surge suppressor/line filter that I use as an example. Its specs that are relevant to noise filtering, which are certainly measurable as well as probably being analytically predictable to a reasonable approximation, are as follows:

EMI/RFI Filter Response (bi-directional, wave tracking): With 50 ohm Rg load: 3db at 5kHz; 26dB at 100kHz; 38dB at 300kHz.

Let-Through Slew Rate: 5,000 volt/µs disturbance reduced to 28v/µs within AC power wave envelope, and less than 10v/µs outside the power wave envelope.

As with most designs, presumably those characteristics were chosen based on what the designers considered to be a preferable set of tradeoffs between the likelihood of audible benefit; the likelihood of undesirable side-effects; development cost; manufacturing cost; parts availability; physical characteristics; target selling price; marketability; profitability; utilization of available human, equipment, and intellectual property resources; etc., etc.

But can they, or any other manufacturer of such products, predict with any confidence what sonic benefits and/or side-effects will result when a product having those kinds of specifications is used in an arbitrarily chosen system powered by AC having arbitrary and unknown characteristics? The answers to those rhetorical questions seem clear.

And this from another member:

03-20-14: Rodman99999
To really view the noise, riding your AC lines; a Hewlett-
Packard 3577A Spectrum Analyzer is handy. Typical line
noise will be seen from 100Hz to 1mHz (and beyond).

Best regards, and best of luck.
-- Al

Thanks all for the input.

Needless to say I was hoping Al would chime in. Very thoughtful and knowledgeable input, as usual from you.

So it seems unlikely I will get much value out of the analysis/measurement I have in mind. Will check out the cost and see if it's still worth pursuing.

Was wondering if the AC conditioning equipment manufacturers might be able to help. Of course they would give me a biased point of view, and it will be tough getting to the right people, but wouldn't PS Audio / Equi=Tech, Furman, etc know in what situations their products tend to work best? Maybe this reasoning is right, but implementing it might not be feasible.
Which companies do you suggest I contact for this?

From reading the exchange between Al and Mapman that Al linked to, maybe a different approach is asking around here which regeneration/conditioning devices have worked best for others using my pre and amp, and hope the results are repeatable at my place. A very un-professional approach. :-) but maybe that's the best I can hope for now?

Psag, I know Shunyata makes good products, but if my AC had "incomplete" sine waves (like those observed on a clipping amp) then a passive filter would not be able to correct that. In that case a regenerator would make more sense, I think. Too bad I don't know people in my area with power treatment equipment I could try at home.

Good point. In my case, I felt that the supply to the house was more than adequate: Suburb, newer construction, no noticeable fluctuations with other high current appliances in the house. If on the other hand I was living in a more urban setting with older wiring and a history of electrical issues, I might have been more inclined to try an active product.

Thanks very much for the nice words, Lewinski.

Yes, I would think that researching and/or asking about what power conditioning approaches are used by others having similar equipment could very well help shift the odds of success in your favor. I'm less confident about how constructive talking to manufacturers may be, but I suppose it can't hurt. I have no specific recommendations to offer about which ones to talk to.

FWIW, based on the many threads I've seen over the years about this subject my perception has been that more often than not (though not by a big margin) people tend to settle on plugging their power amps straight into the wall. At least in the case of amps such as yours which operate in Class AB, and consequently have AC current draws that vary significantly with the dynamics of the music.

Also, my perception has been that reported experiences with regenerators seem to be about evenly divided, with some reporting positively and others reporting compromised dynamics or other issues.

FWIW, I've chosen a "less is more" approach, using this BrickWall surge suppressor/line filter, with everything plugged into it (for purposes of protection as well as conditioning). A number of other members use it also. In addition to incorporating an excellent approach to surge protection (which you can read about at their website) and some degree of line filtering, it also provides filtering between each of its four duplex outlets. That can help keep digital noise out of analog components, and noise generated by power amplifiers out of upstream components.

I should add, though, that I live in an area that I suspect has relatively good power quality, the town having no industry, almost no commercial development, and low residential density. Also, my amp operates in Class A, so its AC draw is essentially constant regardless of the dynamics of the music.

Best regards,
-- Al