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Old 27th December 2010, 07:46 PM   #8101
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Oh really? Are there no IEEE standards for shielding, line and load regulation, and AC ripple? No regulations for impedence. No standard for rating power supplies capabilities according to established specifications and accepted test procedures? What about FTC or can you just make any claim for any power supply?
That is correct there are no IEEE standards it is covered by UL which is now following IEC practice. The main issues are safety! The FTC relaxed the rules on power amplifiers and if you find any concerning audio equipment internal power supplies let me know.
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Old 27th December 2010, 07:47 PM   #8102
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Originally Posted by Joshua_G View Post
I haven't done it, however, none of it explains audible differences between different power cords and power distribution boxes.
Try it, it ain't hard. Let me know.
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Old 27th December 2010, 07:48 PM   #8103
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There are no IEEE standards for subjective differences with line cords. That is the important problem that needs to be discussed. (Life member of the IEEE, please remember)
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Old 27th December 2010, 07:50 PM   #8104
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Simon, usually we use power cords that are KEYED and consistent to each other. Reversing is but another variable.
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Old 27th December 2010, 08:11 PM   #8105
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Quote:
Originally Posted by Soundminded View Post
Oh really? Are there no IEEE standards for shielding, line and load regulation, and AC ripple? No regulations for impedence. No standard for rating power supplies capabilities according to established specifications and accepted test procedures? What about FTC or can you just make any claim for any power supply?
None of the above determines the inner PSU's immunity against RFI carried on the mains supply.
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Old 27th December 2010, 08:13 PM   #8106
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Originally Posted by simon7000 View Post
Try it, it ain't hard. Let me know.
I will. However, right now I'm in the process of installing isolation transformers to various pieces of gear. They may change the picture.
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Old 27th December 2010, 08:21 PM   #8107
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Originally Posted by Joshua_G View Post
None of the above determines the inner PSU's immunity against RFI carried on the mains supply.
If there are no standards and no measurements, how do you know a different power cord works? How does it work, shunt capacitance? Series inductance? A few pf added to all those hundreds of ufs in all of the rest of the wire? Say are you in the audiophile power cord business?
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Old 27th December 2010, 08:40 PM   #8108
wrinkle is offline wrinkle  United Kingdom
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Quote:
Originally Posted by Soundminded View Post
Oh really? Are there no IEEE standards for shielding, line and load regulation, and AC ripple? No regulations for impedence. No standard for rating power supplies capabilities according to established specifications and accepted test procedures? What about FTC or can you just make any claim for any power supply?

Simon is referring to the transformer hot side of the mains may be outside the windings or the inner part of the windings next to the laminations, there is no standard for that. He has discussed that earlier in this thread.

Wrinkle.
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Old 27th December 2010, 08:42 PM   #8109
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I will. However, right now I'm in the process of installing isolation transformers to various pieces of gear. They may change the picture.
Save your money, try it first
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Old 27th December 2010, 08:59 PM   #8110
hags is offline hags  United States
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I have heard differences in power cords too. I guess that is a subjective 'fact'.
Being a big skeptic when it comes to AC cord "cable magic" and their influence on sound after rectification I have to agree that I too have heard differences.

Whether this is due to quality of materials, geometry, shielding, connectors or listening room humidity I don't know. I suppose there are as many theories as their are skeptics.

I wouldn't call them facts, maybe more like eyewitness testimony.
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