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Interesting views, all. Thank you. And great to have input from Gary Galo, whose credibility for me is very high, as we both work in similar facets of audio. I haven't had a chance to try regeneration, but hope to eventually. For small monitoring systems, it is practical. Unfortunately not for larger facilities, as Corey points out.

Some years ago I was surprised by a utility crew, which came by to install a transformer right at my drop. I think there was only one or two serving my city block, and one of the guys said the new unit should help stabilize the line. Of course I played some music as soon as they were done. Sadly, I couldn't convince myself there was a difference. It is shared with three other houses. Maybe if my gear was more sensitive to the AC, it would have benefited more from the transformer, or from the newly bonded ground and power connections. I may also have less interference than a resident of Tokyo suffers.

We old-timers may be fully aware of this, but I always encourage audiophiles to have a dedicated circuit or two installed for their hifi. When I moved about 15 years ago, it was one of the first things I did, as my stereo was sounding like crap compared to what was going on in the old place. Living there in an older neighborhood, I was aware of the variation of sound quality day vs. night. That house was near by an antenna farm, so I had wired up shielded Romex with isolated grounds. Didn't go that far in the new place, but non-spliced runs on new breakers brought the magic back, with less variability than before. The service was 30 years old, so I tested and reinforced the ground straps. I couldn't measure voltage drop on the panel, but I wanted to be sure it wasn't contributing noise.

Some systems prefer to have all components on the same AC circuit. I've found that's often the case with tube gear, or products such as Naim systems, which are very concerned with common grounds. Remember turning the plugs each way to find the best orientation? Can't really do that now, and it probably isn't necessary with modern designs. When I was using a power-hungry Bryston amp, it definitely liked its own AC line. My current Benchmark components seem happier sharing. They use switching power supplies. I wonder if Gary looked into the effect of the regenerators while auditioning the DAC2/AHB2 system.

Anyway, I'm reminded of what I was told years ago when first getting serious about hifi: everything matters. If it matters to you. It can lead to madness. Or to joy.

We all can either lament or fear hearing loss. But, reading about the research behind the MQA coding system has turned me on (within my limited understanding) to the idea that high frequency perception isn't the only thing our sense depends on. Fortunately, other factors that are not so subject to aging are maybe more important. Note that our Japanese colleague spoke of dynamics, imaging, and clarity, which are not primarily dependent on bandwidth. My older brother, a professional brass player, has significant loss of sensitivity, an occupational hazard. We were together just last week and I made many adjustments to his hifi. He heard pretty much all of it, just at a volume level that I could hardly stand. But concert-like levels are non-negotiable for macho trombone players!

-----Original Message-----
From: Association for Recorded Sound Discussion List [mailto:[log in to unmask]] On Behalf Of Corey Bailey
Sent: Tuesday, August 16, 2016 2:44 AM
To: [log in to unmask]
Subject: Re: [ARSCLIST] Fwd: [ARSCLIST] : Fancy speakers? Check. Sub-woofer? Check. Electric Utility Pole?

Dennis is correct:
The incoming power from the outside world is extremely dirty and needs aggressive treatment. The key is to have plenty of current available. 
About a 2-to-1 ratio (1/2 stress engineering) is desirable and the treatment starts from there. Having plenty of current is the only possible reason I can think of that would justify a separate power drop. 
Regeneration is a valid plan if your needs are modest. However, it's not cost effective for large installations.

As Ellis Burman pointed out, commercial recording facilities use isolation transformers. I have built several studios and the electrical feed starts with a center tapped, isolated, 3 phase transformer. The system is branched out, further filtered and isolated from there. The end result needs to have a common, but separate, ground from building power.

Cheers!

Corey
Corey Bailey Audio Engineering
www.baileyzone.net

On 8/15/2016 5:04 PM, Dennis Rooney wrote:
> ---------- Forwarded message ----------
> From: Gary A. Galo<[log in to unmask]>
> Date: Mon, Aug 15, 2016 at 7:00 PM
> Subject: Re: [ARSCLIST] : Fancy speakers? Check. Sub-woofer? Check.
> Electric Utility Pole?
> To: Dennis Rooney<[log in to unmask]>, Seth Winner< 
> [log in to unmask]>, _Steven<[log in to unmask]>
>
>
> Hi Guys,
>
>
> These folks are not crazy when they talk about the contaminated power line.
> If you've ever looked at it on a distortion analyzer, it's appalling. 
> But, I wonder if getting your own pole and transformer solves the 
> entire problem. There's a lot of high-frequency noise on the power 
> line, for sure, and there's no question that it audibly degrades the 
> performance of most audio equipment. But, an equally-serious problem 
> is  the flat-topping of the waveform. The AC power line is supposed to 
> be a sine wave, but it always shows visible flat-topping, like an 
> audio amplifier being driven into clipping. The flat-topping is caused 
> by all the non-linear loads connected to the AC line. I seriously 
> doubt that even having your own transformer would get rid of this, 
> since the transformer would have to have a narrow enough bandwidth to 
> begin attenuating at the 3rd harmonic in order to do so. Having your 
> own pole and transformer will isolate you from your neighbors, and all 
> of the noise generated by their appliances, computers, etc., but I seriously doubt that it will get rid of the flat-topping.
>
>
> I converted from conventional AC line filtering to AC regenerators 
> about five years ago. The regenerators are made by PS Audio - they 
> generate an entirely new 60 Hz sine wave and step it up to 120 VAC. I 
> have three of them - one on each mono power amp, and one on my 
> low-level equipment (preamp, digital player, D/A converter).
>
>
> The regenerated AC is free of both flat-topping and the high-frequency 
> noise that plagues the AC line. I've measure 3 to 5 % harmonic 
> distortion on the AC power line. The output of the regenerators has 
> less than 1% THD even under load.
>
>
> To me, AC regeneration is a saner and, I think, ultimately more 
> effective solution to the problem than getting your own pole.
>
>
> Feel free to post my comments on the ARSC Listserve, which I am not 
> on. I'm sure many people think that this topic is not worthy of 
> serious discussion, but they're dead wrong.
>
>
> Cheers,
>
> Gary
>
>
> Gary Galo
> Audio Engineer Emeritus
> The Crane School of Music
> SUNY at Potsdam, NY 13676
>
> "Great art presupposes the alert mind of the educated listener."
> Arnold Schoenberg
>
> "A true artist doesn't want to be admired, he wants to be believed."
> Igor Markevitch
>