When posts are too ambiguous we must guess the intentions of the poster, specially of those who are fluent in latin....
This will make your head spin... Synergistic Research Atmosphere
- Thread starter Peter Breuninger
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When posts are too ambiguous we must guess the intentions of the poster, specially of those who are fluent in latin....
When posts are too ambiguous we must guess the intentions of the poster, specially of those who are fluent in latin....
Vanitas Vanitatum, Omnia Vanitas
It went from 140 watts to 100 watts.
lol! -the batteries were fine.The amp in question was our MA-1, which is a vacuum-tube amp. When the voltage dropped across the cord, not only did the B+ sag a little, but so did the filament voltage as well as the voltages in the driver circuit. None of them were all that much (for example the distortion in the driver and its gain are unaffected by much larger voltage changes than that!) but it all added up. You can measure similar changes on almost any amplifier that might be more or less dramatic depending on the amplifier and the power cord.
The raw voltage drop across the cord is not the whole story. I have covered this BTW elsewhere on this forum. You can find power cords wherein the filament voltage does not sag, but mysteriously, the B+ voltage is down for some reason. This happens because the power cord limits current at high frequencies. Power rectifiers only commute for short durations but their current waveform should be pretty steep if the power supply is to be charged up correctly. For that you need a little bandwidth in the power cord. It happens that ROMEX is not bad at all, but its illegal to use it in a power cord. But that explains why that last 6 feet can make an audible difference. However many customers have reported changes when they have rewired the audio room. I hate for this stuff to be a variable, but I hated it more back in the days before I had figured out why power cords were audible. It really made me mad because most high end audio power cord manufacturers gave snake oil reasons for why their cord worked- giving me the idea that they really didn't know either. Its one thing to not know- and another thing to not know except that you know for sure that you are being lied to.
All that and I get a simple math problem wrong. Sheesh.
The cord in question would run warm when it was operated over a period of time. It was a generic cable, rated at 15 amps.
I've seen plenty of cables that warm up at their connectors. That is never a good thing- not only is it not the safest thing, you are guaranteed a voltage drop on the connection.
The cord in question would run warm when it was operated over a period of time. It was a generic cable, rated at 15 amps.
I've seen plenty of cables that warm up at their connectors. That is never a good thing- not only is it not the safest thing, you are guaranteed a voltage drop on the connection.
Actually not at all would the statement apply both ways. The objective crowd can test out things against physical reality. The subjective crowd doesn't, and if they do a great many of the normal concepts they hold and use for decision making fail the test vs the reality out there. Sorry, it just is not so that every opinion is equally valid.
Not exactly a compelling case for expensive aftermarket cords though. A heavy gauge el cheapo home depot copper cable will have the same loss as a heavy gauge mega bucks audiophile cable. This is simple physics.
Yes, I agree, so long as the Home Depot cable has good bandwidth.
In my original post I was careful to point out that the cord need not be expensive. But if you want good connectors that don't heat up and you are in the business of selling power cords, its going to cost around $150 minimum. In the pantheon of power cords available in high end audio, that is a drop in the bucket.
In my original post I was careful to point out that the cord need not be expensive. But if you want good connectors that don't heat up and you are in the business of selling power cords, its going to cost around $150 minimum. In the pantheon of power cords available in high end audio, that is a drop in the bucket.
I doubt the capacitance in that configuration is enough to matter at all at audio frequencies. Anyone with a HOT could measure the capacitance with a multi-meter and get an idea. In any case, they have arranged for one to be tested for its effects when transferring signal next week. We'll know after that if it does anything. As for post #24 showing expectation bias, I guess it depends on how you look at it. Like objective approaches usually, one can check it against known factors of electrical signal transmission. When someone does this it looks like it would do nothing. But to be sure it is going to be competently measured for effect. My guess with what I have seen is that it will do nothing audible to the signal. In a few days we'll know.
I do find the faith in the company and product so high that a defense is made for such a product is rather amazing at this point.
The fact that additional testing is being conducted to determine whether the capacitance is sufficient does reflect the fact that the derisive dismissal following the tear down in post #24 was premature, hence a reflection of a bias. And finding that the capacitance is insufficient will not rule out the possibility of an alternative mechanism.
And to be clear once again, I am not defending the product or the company, but arguing about the approach. Care should be taken to ensure that one has a complete understanding of all possible mechanisms through which a device could function before using a theoretical argument to dismiss empirical evidence to the contrary.
Bandwidth on a power cord should hover around 60Hz. You don't want high frequency power line noise anyway.
Good hospital connectors can be purchased for $10-15 and they won't heat up.
Actually I just explained why you do in fact want wide bandwidth in the cable!
FWIW, a few bits of foil if not coupled tightly together as seen in an actual film cap are not going to amount to much in terms of capacitance. And even if they did, this is headphones we are talking about- the timing constants due to the output impedance of the headphone power amplifier are going to be quite high- probably in the MHz region. Hate to say it, but from what I have seen of this headphone thing so far, it stinks.
Now if they are doing something with the ground wire- if you just separate the ground of each channel of the phones going back to the power amp the difference is pretty dramatic (in the headphone world this is known as the '4-wire' connection). I did not see anything to suggest that in the photos.
FWIW, a few bits of foil if not coupled tightly together as seen in an actual film cap are not going to amount to much in terms of capacitance. And even if they did, this is headphones we are talking about- the timing constants due to the output impedance of the headphone power amplifier are going to be quite high- probably in the MHz region. Hate to say it, but from what I have seen of this headphone thing so far, it stinks.
Now if they are doing something with the ground wire- if you just separate the ground of each channel of the phones going back to the power amp the difference is pretty dramatic (in the headphone world this is known as the '4-wire' connection). I did not see anything to suggest that in the photos.
Wise words. However since the disagreements start in the capabilities, objectives and methods of stereo sound reproduction we will never reach an agreement on "all possible mechanisms".
Fully agreed. In my field (social sciences), it is accepted that complete theoretical modeling of complex phenomena is impossible and mathematical models are used only as a working approximation of reality. Whenever the models clash with empirical evidence, it is always the appropriateness of the assumptions on which the models are built that is questioned first.
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Good post, dismissing reported phenomenon as imaginary without experience and careful examination seems like one of the least scientific things you could possibly do.
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