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In Reply to: RE: Update v0.3: The Art of building Computer Transports posted by cics on September 14, 2007 at 15:07:18
Spinning things is always a bad idea. In a Computer Transport, each HDD involves 2 motors for spinning disk platters and moving read/write heads. Although BLDC motors have come a long way, they still put back power noise into the system. Of course, as pointed out previously, this can be minimized by sourcing power from non-mobo 12V rail. However, not having such power pollution in computer is preferred.
I’ve been keen to get SSD technology (as no motors are involved) but found this to be difficult and in computer terms expensive – it’s still a few months away. I’ve been searching to find another way to eliminate such noise using conventional HDDs. SATA technology lends itself to external use (called eSATA) and this is where my journey started. I wanted to power my 2 laptop HDDs from another power source.
I didn’t have to look far at all! Here’s the solution (ViPowER’s VP-9101P):
For a princely sum of 2 x $33 this power supply unit connects directly to my laptop HDD. SATA cable in turn connects to mobo (it’s shielded and long - be careful routing within case making sure connectors don’t accidentally dislodge). Simple.
Each HDD requires a dedicated power unit. In my setup, these 2 tiny ‘bricks’ lie on floor with power lead going into Zalman case. All dirty power components (LCD screen, 2 HDDs) are isolated to a dedicated line filter (basic variety). Computer has its own same dedicated line filter.
This means computer PSU sees no HDD load, i.e. HDDs with NO power consumption! Finally, no more spinning things interfering with music playback (no PSU fans, no CPU fans and HDD motors powered externally).
After allowing for burn in time, it was time to play. Sound improved on what was already brilliant! Music is more involving & emotional with richer harmonics, improved micro dynamics, cleaner highs & mids, and tighter cleaner bass. If you have desktop drives, improvements would also be audible (although standard desktop drives are noisy and generate terrible vibrations which negatively impacts jitter).
I’m going to start a change log for version 0.3 as this is a must do!
Follow Ups:
Well...I could not find the ViPower VP-9101P, but I did find another product here in California, so I ordered it. It's made by Addonics (see link below).
When I first plugged it in, I thought I was going to have to pick a specific passage in a song and listen real closely to discern a subtle difference. But then as I listened, I noticed a difference right away without even trying. I thought it must be a placebo effect, so I switched back and forth a couple of times and found that it was not subtle at all. The soundstage got bigger, the quiets got quieter, and there was more separation (or air) between vocals and instruments. In other words, the instruments did not interfere with the other instruments nor the vocals. Still, I figured I needed to do a blind test to be fair, so I asked my wife to listen. She had no idea what I bought or what I was doing, she just thought we were going to compare software settings or something. So without telling her which was which, I played a song with the external power adapter and without (with computer PSU). She typically gets frustrated doing listening comparisons for me and has trouble discerning differences most of the time, but this time was different. She was like WOW! She thought it was an entirely different song I was playing. She thought it was a different version or we were comparing low bitrate MP3 with WAV or something. It was that obvious.
So cics, good call! This is a definite improvement.
Can you please email me? I'm interested in replicating the use of these power souces for my internal hard drives. I am a newbie to pcaudio and would like to confirm some things before I tackle this. Thank you.Theobetley@comcast.net
Why not try a external Esata drive enclosure with a low noise drive, see
http://www.storagereview.com/Testbed4Compare.sr they do test noise, heat, power, etc and a 500Go 3.5" hdd can be lest noisy than a 2.5" hdd. The other advantage is the heat is outside the computer case, so cooling is easier.
Thanks - my experience is same. I'm most impressed with excellent micro-dynamics in vocals. I've never heard this level of clarity in vocals across any system including analog.
Its a significant improvement as jitter is substantially reduced.
Addonics looks very similar to ViPower's with same pin based power connection. Another alternative is Granite Digital (also based in California).
With motor power noise removed from transport, RAM electrical interference becomes more noticeable. Relaxing latencies from 3-2-2-? to 3-3-3-? complements this optimization nicely. Overall, I get a more musical experience.
Note all other RAM settings should be left as is (i.e. command rate 1T, 4 bank interleave etc.).
Cics- what makes you think using a small separate SMPS to power the HDDs is going to be any better than the PC's main PSU?
From:www.playtool.com/pages/psumult...
"The real issue is whether the power supply provides enough total current at 12 volts (as well as the other rails) and not whether it has multiple 12 volt rails."
ViPowER doesn't give any specs for the VP-9101P on their website, have you measured the noise levels of the ViPowER’s VP-9101P, are they lower than the Zalman PSU?
Have you measured the current draw from your HDDs? Are you exceeding the current capacity of the Zalman PSU?
Without any proof that your feeding the HDDs with lower noise or exceeding the current capacity of the Zalman PSU, I think you're just imagining any improvements.
If you want to improve the power going to your HDDs, stop looking for plug & play solution like the ViPowER and try a linear PSU.
See response at Audiogon thread.
See response at Audiogon thread.
These measurements were taken a few weeks ago.
To understand impact of HDD power interference, I used my DVD Computer (which I consider to be a dirty environment). This computer uses 2 standard SATA desktop drives which impacts both 5V & 12V lines. Measurements are done using Elab-80 DSO at 80MHz. Dynamic range is 48db (8 bits).
Scenarios tested:
1. Machine at idle
2. 500GB HDD spins down whilst remaining HDD continues
3. Same 500GB HDD removed whilst remaining HDD continues
Both 5V & 12V lines measured. Computer remains idle in all measures. Measures were repeated.
Left diagram shows ripple noise with spectral view on right. Both 5V and 12V lines show healthy reductions in interference. I plan to do similar measurements on my Computer Transport with and without VP-9101P.
----------------------------- 5 Volt line -----------------------------
5V @ idle (both HDDs spinning)
5V @ idle & 500GB HDD spinned down (i.e. no motor activity)
5V @ idle & No 500GB HDD (physically disconnected)
----------------------------- 12 Volt line -----------------------------
12V @ idle
12V @ idle & 500GB HDD spinned down
12V @ idle & No 500GB HDD (physically disconnected)
You don't need VP-9101Ps to clean this up, just put a 470-1200uf cap across the 5V rail at the HDD end of the connection.
Try some Rubycon ZA,ZL or ZLGs.
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