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In Reply to: Vintage audio power supply posted by JWPATE on December 31, 2003 at 08:33:47:
What you need depends to a significant degree where you live. In a major city, the power is pretty "dirty" and there are huge currents flowing in the ground returns. But if you're in a smaller town or a bedroom community, you don't need as much.I personally think that most of the power conditioning and expensive cord sets are pure marketing hype. What does fixing the last 6 feet of wire do for you when there's hundreds of feet in the walls that is just plain wire?
I'd try a good power strip such as you describe as the first step. If you feel you might be getting some digital or RF noise coming in on the power lines, add some ferrite clip on thingy's to each power cord. They cost a few bucks each and Radio Shack has them.
If the contacts in your wall outlet are loose or sloppy, you might want to consider a new receptacle. Hospital grade buys you little except an isolated ground, requiring a separate ground lead to the receptacle. You can't use the box as the ground path. But that does no good unless all the outlets and switches, and lights on that branch circuit are also hopital grade and a separate ground wire is run all the way back to the main box, ideally a separate ground wire for each outlet! As you can see, most guys who fool with this stuff just make themselves feel good without really doing anything useful.
"It sounds so much better!" The old Placebo Effect at work once more. I'd bet you could replace their power cords with cheap stuff without telling them, and they'd never know.
Jeez, I can feel the flames already. But then I used to specify the wiring for, and work in, instrumentation labs, so I know what it really takes.
Follow Ups:
What does fixing the last 6 feet of wire do for you when there's hundreds of feet in the walls that is just plain wire?What does fixing the first 6 feet of wire do for you ?
What you are filtering is grunge from other sources, especially digital ones as well as other sources of interference in your house, not the power source.
Your argument holds for line filters, but not for power cords or plugs, which is what I directed my comments at. I have used line filters in some cases.
JPS Labs cords (among others) are highly shielded and the ones designed for digital use frequently employ some conditioning.
Sure power cords can be antennae, so can all the unshielded wire in your walls. And unless you have a line filter, the shielding does nothing at all. In fact if the filter is at the input to the component, a shielded power cord is pointless. The filter would have to be in the plug/receptacle to make a shielded power cord usefull. Sorry, I just don't buy the argument. My Rotel CD player has a very nicely implemented line filter just inside the chassis. What would a shielded power cord do for me?
Jerry, I think you're probably right. It'd be fun to pull such a stunt then see the look on their faces, but then on the other hand, you may get yer head smashed for messin with their hygh dollar cables. ron
I've long wanted to sneak in and pull tricks like that. It would expose a lot of the hype and BS that clutters the audio world, and obscures some of the real issues.John Dunlavy has written about similar tricks in evaluating speaker cables. Like pretending to switch cables from 12 gauge to some impressive looking stuff, and having the subject proclaim it sounded better. Or mixing up the indicators on their switch box so that the subject thought he was listening to the exotic when it was really something else. He always picked the one he thought was the exotic. I suppose after you told them the truth, you could have a contest to see who's face got the reddest, and who's veins stuck out the farthest on their foreheads.
Thanks Jerry,
That is exactly what I will do. I live not too far from the Hoover Dam, but between here and that power source, is the City of Las Vegas.
James
You said:
Be advised that hospital grade receptacles are not isolated ground receptacles. An isolated ground receptacle can be had in hospital grade or most any grade you desire. But a hospital grade isn't by default an isolated grade. Just thought you might care to know. This, I know, as I have worked in the hospital engineering field for the last 20something years.
Russ
P.S. I highly encourage you to read up on balanced power. It's not hype and is based on solid engineering. In a hospital, it is widely used in operating and critical care areas, just under a different name, isolated power, and for different reasons. Only recently has it gained acceptance for audio and is now part of NEC for recording studios and such. I have had very favorable results in my audio system with it. It's less about providing clean power and more about giving the noise a way to self cancel.
Russ,Thanks for the heads up. I've always specified isolated ground receptacles for the calibration areas and other critical instrumentation areas. A separate pulled ground wire for each receptacle (star grounding, basically). In the last good lab I had, we used a triple Faraday shielded isolation transformer for our power, and the ground for the lab was 6" diameter, 3/8" wall copper pipe run under the computer flooring. That was tied to a driven ground that was dedicated to our lab. I get the idea of balanced power, you're saying it makes the noise common mode? It would seem to be common mode in the secondary only if it comes in from outside, on the primary. Noise generated on one leg from the secondary side would not be, would it?
If hospital grade doesn't get you an isolated ground, what makes it hospital grade?
Mostly what hospital grade gets you is a more rugged receptacle better able to cope with abuse....and really , superior blade retention. A good hospital grade receptacle and plug (cord cap) will make you feel like you are going to break the drywall or rip the whole nine yards out when you try to plug and unplug it.As far as common mode and all of that with balanced power ....well just do a search and read and see what you think. It's pretty clear to me that you have a good deal of knowledge and I will leave it to you to decide it's merits or hype. I can only tell you that I feel it's well worth the money and effort. But I wouldn't pay $500 for an "audiophile" unit:).
If one was to try it the, first thing I think you would notice is a real total absence of background noise. You can fire up the system (phono stage even) and crank it to full volume and hear nothing....really you can't tell your equipment is on until you play something. Then little by little you notice a great increase in low level detail....stuff that was somehow hidden that you never missed...also a reduction in glare/hard edged transistor sound/digital artifacts.
It is not by any means a cure all for a bad system but instead something that helps all parts of a good system perform at their best. Just like the steps you have taken in the lab's electrical system. Likely the better the lab's euipment the more pains you would of taken rather than say the better equipment has less need for clean power due to it's superior filtration and such inside the equipment. Of course YMMV and certainly your stereo as well as incoming power all play a part in it's potential contribution in your household.
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