This is a review and detailed measurements of the Nordost Blue Heaven AC Cord. It is on kind loan from a member and costs US $417 at this length (2m).
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This is "third-tier" product in Nordost line so naturally, it is not going to scream expensive. That is a good thing as the cable itself is kept to less than crazy thickness. It is flexible but doesn't want to rotate which is a requirement for AC cord. Fortunately the connectors are easy to plug in and the weight was not excessive enough to yank your gear off the table/rack. I like the beefy plugs that make it easy to handle the cord. Here are the marketing claims:
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I must say, I had not heard of "high-speed" as something good in AC cables. After all, high-speed means no filter or else, it would not be high-speed! We will test for its speed in the measurement section. I got a chuckle out of the claim that their claims are "proven." Naturally no such proof was provided.
While the plugs have UL/CE marks on them, the whole assembly has no mention of safety regulation either on the packaging or the marketing material. Only conclusion then is that the cable is not certified which is a sad thing when it comes to something that handles high current/high voltage and can cause safety risk.
Nordost Blue Heaven Measurements
Every time I go into one of these tests I think about how to expand our testing and come at the product from a different angle. While some of this testing may seem familiar, some are new. As usual, comparison is against a generic cable I had handy. In this case, I had a white AC cable that is marked as "I-SHENG" and comes with UL mark on the cabling. Company website says:
"Isheng Electronics is a world-class manufacturer of AC power cords. We offer a wide range of power cords including different NEMA AC power cords and different International power cord configurations. "
There is mention of speed of proven technologies; only that they are safe.
As usual, I perform my high-voltage tests by sensing the wavefrom using a B&K high-voltage differential problem with 100:1 attenuator. Here is my AC waveform using the I-SHENG generic AC cord:
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We see that the tops of the AC waveform are deformed resulting in a lot of harmonic distortion and noise. Treating this as if the power company is an amplifier, its SINAD is 31 dB. Let's swap in the Nordost Blue Heaven and see if it makes a difference:
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It doesn't make any difference. Everything bad that was there continues to be bad.
Some say my power is clean. I don't know how anyone could say the above is clean but let's use my B&K AC generator to create a highly distorted waveform, simulating what a dimmer would do:
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Let's agree that is one bad AC waveform! Our SINAD has now sank to just 5.3 dB! Let's pump that into the Nordost Blue Heaven and see if it does anything to it:
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Once again it doesn't.
While we are here and have an AC waveform that has nice sharp transitions, let's look at it in time domain with bandwidth of the analyzer expanded to 1 MHz. Here is the comparison:
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There are actually two waveforms there: one in blue for Nordost and another in red for generic cable. As you see, every pixel has landed on the other demonstrating that there is no difference in any aspect of that AC waveform including its sharp rise and fall time.
So far we have measured the AC waveform. Contrary to what Nordost claims, your audio gear doesn't run on AC. That input waveform is converted to DC and filtered heavily before use. It then drives the electronics that makes audio signal. That is all we care about as that is what we hear, not the AC waveform. So let's test for that.
Topping A90 Power Cord Measurements
Let's use the
Topping A90 preamplifier/headphone amp that is on my desk to test the difference starting with generic AC cord:
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Once again we get the superlative performance we expect. Now let's switch cables to Nordost:
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Once again no difference.
Let's finish with a proof point of why AC tweaks don't work. I used the chopped dimmer AC waveform and fed it to Topping A90 with the generic cord. Here is the output:
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Yup, there is not a hair out of place! We have the same superb performance coming out of headphone amplifier even though we nearly destroyed the AC waveform! That chopped up waveform in blue when it, and what came out was the red.
Conclusions
Both our old and new tests prove once again that power cords make no difference (as long as they are thick enough to handle the currents you need). We expanded our tests into time domain and saw no improvement with the Nordost cable. If the cable can't change the AC signal, surely it means that the output of our audio gear remains the same and that was indeed the case. We then proved our conclusions by supplying our test audio product with highly distorted AC waveform and its performance didn't change.
You can buy an AC cord on Amazon for about $10. It won't look as fancy as the Nordost but you can sleep easy knowing that it is safety tested and costs 40 times less!
As an aside, the owner was sold on this cable by an audio salesman that made it sound like his gear would not be complete without it. He couldn't hear a difference so sent it to me for testing.
I can't recommend the Nordost Blue Heaven Power cord.
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