rgro wrote:
> It is not the typical hawking of $1,000/meter cables or claims of that
> ilk. I'm not edumacated enough to know if John's theories, as he's put
> into practice, are sound science. But my lay read of his explanations
> would suggest that there's some merit here.
>
> http://uptoneaudio.com/pages/j-swenson-tech-corner
>
> It would appear to me that this REGEN device is contributing to reducing
> some kind of analog noise that almost any USB dac would produce,
> internally.
>
Lets say that your house has some lead plumbing that contaminates the
drinking water within. Here's the challenge: What can you do to the pure
water that is delivered to your house to get the lead out of the water
that comes out of the faucets in the house? There is a reasonable
answer, and that is by pre-processing the water to decrease any acidity,
the leaching of lead from the water pipes in the house can be reduced.
Reading the cited document, it appears that the USB equivalent of
contamination of water by lead plumbing in your house is:
"When the SI is very good, the PHY can turn off the pre-processing steps
and easily determine the bits. As the SI degrades the PHY turns on
different parts of the pre-processing as needed. Each of these steps
takes a fair amount of power to operate, thus creating noise on the
power and ground planes. The more processing the PHY needs to use to
determine the bits, the more noise is generated. Thus part of the packet
noise is directly related to the signal integrity of the incoming
signal. The higher the SI, the lower the noise."
There are a number of contingencies that are cited in this paragraph:
(1) The USB signal must have poor SI for the regenerator to have any
benefits because if USB signal's SI is good, there is obviously no way
to improve on it. The leading cause of poor SI on high speed USB signals
is excessively long USB cables with excessive high frequency losses.
(2) Given that the USB signal has poor SI, the claim is made that poor
SI causes additional processing to be switched on inside the USB device,
and this processing draws excessive current and degrades the signal
quality that the device can possibly deliver.
Any claim that all audio systems have problems with poor SI is obviously
false. For this product to actually provide any benefits, the presence
of poor SI in any target system needs to be validated. The easiest and
cheapest way to maintain high SI is to keep your USB cables short and
their quality reasonably high. There is no evidence that utterly
expensive high end USB cables are required to do this. If I wished to
validate the operation of this device I would set up a system with
artificially poor SI, for example one with long, poor quality cables.
There are a very large number of different USB PHY interfaces in use
given that millions if not billions of USB devices have been produced
since USB was introduced about 20 years ago. Obviously, not all USB PHY
interfaces are the same. Obviously, not all USB PHY interfaces even have
additional processing that is switched on and off in the presence of a
signal with poor SI. Actually, most of the examples of USB PHY receivers
that have some kind of switching, activate this switching based on the
speed of the equipment they are working with and leave it at that. One
would have to find a USB device that actually significantly increased
its current draw when faced with poor SI. Finally, the myriad of USB
devices would have to be sifted to find those that actually degraded
their audio performance when faced with poor SI if you wanted to set up
a test that showed that this device provided an audible benefit.
It is just common sense - if a device provides benefits by fixing a
problem, then you have to have the problem for the device to be of any
benefit to you.
>
> Not that it validates anything, but there sure seem to be an awful lot
> of folks who are liking the little gadget...and at $175 it wouldn't
> appear that John and Alex are trying to rip people off price-wise,
> either.
One big caution flag about business practices can be found here:
http://uptoneaudio.com/blogs/news/20068483-usb-regen-updated-amazing-bass-all-unshipped-orders-will-be-the-latest
The article says that 'We have added $0.40 worth of tiny resistors to
the circuit board of the USB REGEN and increased its musical performance
by 40-50%—most especially in the bass! Anyone who has a REGEN will be
astonished by the improvement, and anyone who hears the new one for the
first time will be even more amazed."
The obvious question is "What about the 100s of Regen units that have
allegedly been shipped without this allegedly amazing upgrade". The
article says that an entirely new circuit board is required, which means
that you have to essentially replace the entire unit, presumably at your
own cost.
When you are fishing, you wait for the fish to nibble the hook and then
you manipulate the line to set the hook. However, you can only pull in
one fish each time you do this. Looks to me like Uptone Audio has
figured out how to pull in many fish with just one setting of the hook.
;-)
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