[Codifus]

On Nov 25, 11:07*am, Rob Tweed wrote:
Well I ran the Audio Rightmark tests on the EMU with the original PSU
and the Zip drive PSU. *Interestingly there was almost no difference
between the measurements. *See what you think. *I ran 4 consecutive
tests with each power supply. *Everything else was kept identical,
even the power socket that I plugged the supply into.

Original power supply:

http://gradvs1.mgateway.com/misc/emu_original_PSU.jpg

Using Zip drive power supply:

http://gradvs1.mgateway.com/misc/emu_zip_PSU.jpg

And by comparison, here's the results for the cheapo Edirol USB UA-1EX

http://gradvs1.mgateway.com/misc/edirol.jpg

My conclusion is on these measurements alone, I must be imagining the
differences I thought I heard between power supplies, but it at least
vindicates my view that the EMU sounds a lot better than the Edirol!

Bear in mind that the test I ran was the one where the outputs were
connected to the inputs so I was running through both the ADC and DAC
stages of the EMU. *However, since every other parameter was constant,
I was looking for differences in measurements, and not particularly
concerned about the absolute values. *You'll notice that what
differences there were between the tests with the two different power
supplies are barely different from the differences between each test
run for each PSU. *The measurements I suppose are consistently
fractionally better with the Zip drive PSU, but it's marginal!

Rob

On 13 Nov 2008 14:06:06 GMT, "Arny Krueger" wrote:



"codifus" wrote in message

On Nov 11, 7:03 pm, "Arny Krueger"
wrote:
"codifus" wrote in message



I recently learned that the 0404 USB comes with a
"dirty" power supply. It converts AC to 5 Volts of
fluctuating DC. I found an old power supply from a zip
drive I had that puts out 5 V of real DC, or linear DC.
After converting the Zip drives power supply to work
with my EMU, I hooked it up and gave it a listen to my
music in my library again. This is what I found;
Sound was much smoother, especially in the high
frequencies.
The EMU seemed to be able to resolve more as well.
Also, the quiet passages were, um, quieter

The proof of the pudding would be to run an Audio
Rightmark, with each power supply:

The software is free.

http://audio.rightmark.org/downloads/rmaa6.exe

I suppose I could do that, but I do not need to.

Right, you know that you are right, and no tecnical confirmation is
required.

*I know
there was a difference and I'm not about to clarify my
results by posting the technical papers in some science
journal. Rather, I'll take the 5 minutes to try the
experiment and be done with it.

Which experiment?

This is not to say that the technical explanation for the
change would not be interesting to see. I would be very
interested. I just don't have that kind of time. I'd much
rather spend it enjoying the music.

Yes, spending 5 or 10 minutes to do the Rightmark test would separate you
from the music you love, for far to long of a duration.

Besides, I completely destroyed the original power
supply

However, we have another test of a typical unmodified unit.

---

Rob Tweed
Company: M/Gateway Developments Ltd
Registered in England: No 3220901
Registered Office: 58 Francis Road,Ashford, Kent TN23 7UR

Web-site:http://www.mgateway.com

Rob,

thanks for doing the tests. The improvement I observed was subtle, and
I gather that the tests may bear this out. A subtle difference
shouldn't cause a huge change in tests results, should it? Fact is,
the Zip power supply on average was providing better total harmonic
and intermodulation distortion figures. Not much, but it was there,
and it was there consistently. Given that when we listen to music via
the EMU we are only using the digital to analog pathway as opposed to
the round trip that this test was performed on, I wish there was a way
to test the D to A part only.

Also, to add to my initial observations, the change of power supply
was most noticeable in high frequencies. Splashes of treble were much
smoother. Cymbals in the music fizzled more pleasantly.

So while i think that this test shows a little bit of how the improved
PSU bettered the EMU 0404, a better test would be to test the D to A
only, and perhaps do separate tests on different groups of
frequencies; 8000 to 16000 Hz for one test, 20 Hz to 500 Hz, for
another etc. All D to A only.

CD