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Old 26th July 2005, 04:15 AM   #11
kevinkr is offline kevinkr  United States
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Hi Amo,
I think the best you can do is to use a good audio card, hopefully this one has on board linear regulators which will provide some additional isolation between the audio board clock source and the noisy power supply rails. One thought would be to find out what the chip set is on that card and see whether it uses one of the standard crystal frequencies employed in audio - in such a case it might be possible to use a kwak or tent clock setup... Some cards provide options for an external word clock input and this might or might not be useful..

You could use one of the myriad reclockers from ages past (not resampling!) like the ultra jitterbug,etc..

Use EAC for transfering bit perfect copies of your cd's to the hard drive and compress with FLAC - this is the advice I get from several locals doing this and whom I respect.

Wednesday I will be listening to a digital music server that uses these programs and will report back here.

Also use ASIO instead of the windows audio dll and kmixer, you really don't want to resample from 44.1K to 48K as the interpolation/resampling process accuracy over such a very small difference in fs is quite poor.

Finally if you are that concerned about sound quality you ought to investigate a good vinyl playback system. (No I'm not kidding.)

Kevin
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Old 26th July 2005, 04:22 AM   #12
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Your comp hard drive apparently is virtually jitter free play back. I am slowly putting all my stuff to hard drives and the Bup drive AND another stand alone external storege unit. I use the M-audio delta 66 which has a break out box with all the toddy bits like DAC and such in it. Not a peep from the lines or amp with all gains and volume at full blast (no music playing) so i would say it is pretty damn clean noise wise

Head shoulders and a MOUNTAIN over and above the creative sound card for music play back OH and i use FLAC ...very good stuff gets you about 40 percent space or worse but its lossless which is a GOOD thing.
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Old 26th July 2005, 04:24 AM   #13
kevinkr is offline kevinkr  United States
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Today the motherboard, and everything else arrived except the DVD writer and I spent a couple of hours assembling the whole thing.

I will say that the Antec Aria case is very nice and extremely well made, it is also very, very tight.. The triple sandwich construction, low speed fans and HD mountings which are well isolated should make for a very quiet pc.

Everything fit, although not with a lot of room to spare. I tie wrapped most of the wiring neatly out of the way, but if you are a neat freak the limited space is probably not going to float your boat.

I am just waiting for the DVD writer and the AV/S card and will install these when they arrive.

I have the spdif adapter option and will install it shortly - this will be used only until I make a decision on what sound card to buy, that is unless it turns out to be stellar.. (Doubtful..LOL)

I have downloaded most of the software I need for the music server functionality, but have not focused much on the video recorder end of things so far.

I expect in a few days to be able to do the software installation and see what that gets me.. LOL

I still need to address the remote control options, sound card, tuner card..

Kevin
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Old 26th July 2005, 07:12 PM   #14
amo is offline amo  United States
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Thanks for the replies, guys! Some good stuff to chew on¡K

First, I was fairly sure that the big idea behind a high-end studio sound card is all about the good clock, combined with a great on-board DAC and high-end analog output stage. I never really though about using the input for a outboard clock as a method of escaping the jitter the PC itself injects into the already good on-the-card clock. This is a new way of thinking for me ¡V so thanks for that. Also, thanks for bringing my attention to using the ASIO drivers. I guess they are used already, but I did not know that the nasty up-sampling happens in the windows dll files. I always though that this was done by the creative audio cards themselves.

Just a side note, I was thinking about adding an outboard DAC all together, then I would not need a separate clock/word generator. The reason for this, is because as I said before, these cards provide an AWESOME digital output on a transformer-isolated, BALANCED line. Even a $100 EMU card will give you this in spades (ok maybe the $200 cards begin using isolation transformers ¡V not sure). But, this is a little out in the future, and so I am obsessing about everything else for now.

As far as an overbuilt, over-engineered vinyl system ¡V well these look tasty, but unfortunately out of the question for this application. There are far too many albums/artists/tracks/multiple mixes and versions to fumble around with the records (I can¡¦t even do it with CDs¡K). If not for a computerized library management system where anything you want can be queued up in seconds, I am afraid most of this music would be left unheard. And let me say something else: Many audiophiles are simply turning away from a PC-based solution, because they say, there are too many problems. I think that if those EEs, who were experts in these fields devoted some time to the issue, and looked at this as a worthy design challenge, we would have a serious contender to the high end digital reproduction systems, where perhaps, for a very small trade-off in performance, the gains in usability would represent a Return on Investment like few other innovations. A hard drive can happily store 16, 20, 24 bit and other recordings in any channel and sample frequency configuration, and you can manage the media library visually just the same. Compression, storage methodology, etc can also be personalized. If you want to have your precious recordings stored as raw WAVs in a mirrored RAID array with 100% storage overheard, then that can be done just as well¡K

And to my non-EE mind, a linear power supply capable of running all components of the PC would be coming close to where we want to be. I know of at least one DIYer who has built one and has published the details on how to do just this. However, I plan to devote a thread in this forum on investigating how important this really is (hopefully there will be some replies on this subject). If there is little benefit to the components involved from using a linear PS, short of the stray magnetic field, which on a switching PS can be happily contained by using a separate PS enclosure, then I rather not go down this path. On the other hand, if a qualified EE tells me that many of the PC problems are solved with a linear PC power supply, then I will make one if it¡¦s the last thing I do ƒº

Outside of playback, I think the most important thing we do with these things is extraction (from CDs) and encoding (from vinyl, reels, etc)¡K You can change your playback setup as much as you want and be able to replay the rack over and over, but you will extract the audio or encode the audio only once, usually. So I am wandering, how important is a linear power supply for extracting/encoding? Does it even matter, especially if DAE software ¡§guarantees¡¨ a bit-perfect rip? Is it possible for a recording to be ¡§bit-perfect¡¨ but still have nasty elements of noise and jitter injected into the WAV? I guess this is the most important question from all the text in this post. What are the alternatives? A high-end DAT recorder with a balanced digital link to a high end CD player, then just copy the DAT tape to the hard drive? Ok, I need to snap out of this now!
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Old 27th July 2005, 04:47 AM   #15
kevinkr is offline kevinkr  United States
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Quite a long reply.. LOL I can't do it justice.. I think the idea of using a linear supply as the main supply in a pc is probably problematic - there are so many sources of noise in a typical PC and I doubt that the supply is even the major contributor. Basically comparable results could be achieved with better efficiency by heavily filtering the supplies for both common mode and differential mode noise and then regulating them with low noise LDO regulators. I suspect shielding and careful lead dress would also be helpful. The biggest problem with pc's is that they are just one big ground loop with multiple harmonic currents flowing through the loops between all the various grounds. Most motherboards are grounded at most every mounting point, (True of the Antec Aria case anyway) as well as every pci card bracket. They don't radiate more simply because the case achieves a high level shielding, and considerable pains are taken to assure that holes in the case are small relative to the wavelength of the highest frequencies present in the system. Most pc's I've seen interfere badly with radio's and tv's in relatively close proximity - even those on cable where the interference is not present at the antenna terminals.

Transformer isolation for spdif is definitely the best way to go, but I also think that the secondary side of the transformer probably should not be connected to chassis ground in most cases. Sometimes a good common mode choke prior to the transformer is a good idea as well.

Provided the bits stored on the disk are an accurate representation of those on the original with proper buffering and a card with a good clock design, low noise and adequate isolation from internal pc noise sources I don't see how you could get much better.

EAC seems like a good tool for assuring that the copy is faithful to the original cd.

The chip set in my motherboard is not going to cut it, even with a transformer and additional cm filtering to remove noise. I will probably modify the output to incorporate a transformer as a temporary expedient.

Still waiting on the dvd writer, until then no progress..

Stay tuned..



Kevin
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Old 1st August 2005, 03:39 AM   #16
kevinkr is offline kevinkr  United States
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Latest update, I assembled the server over the last few days and spent most the week-end configuring the software. I have so far ripped 3 cds using EAC, converted all the files manually to flac and am using winamp with the flac plugin to play them. Asio is installed, but I am not certain that it is working correctly although everything sounds at least ok. I am using a japanese asio plugin with winamp basic and it does not seem to work too well with asio4all, however it seems it recognizes the audio card as an asio resource so that is how I have it set.

Any idea where to get a more current asio plugin? Winamp does not mention anything at all about asio support and there is nothing on their site about it at all.

I am still planning on feeding the EAC stream directly to the FLAC encoder and I think I have figured out the script I need to add in the EAC "use external encoder" dialog screen.. We shall see.

Incidentally this machine is fast enough to rip, encode, play music and websurf simultaneously.. Interesting - I don't think my older desk top could manage this..

I am using an MSI pci bus wireless card for access to my home network which is both wired and wireless..

The spdif output seems reasonably good, and given the fact that I have been unable to find a sound card that satisfies my criteria I am just going to stick with the onboard spdif for a while..

Haupauge single tuner tv card with hardware mpeg encode/decode is ordered. S-video adapter for my mobo onboard video has not shown up yet.

Incidentally this mobo is easy to configure and performs quite well overall. Better than expected for the money.

Kevin

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Old 1st August 2005, 03:50 AM   #17
andy_c is offline andy_c  United States
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Here is a page that has setup instructions for automatically launching the FLAC encoder from EAC.
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Old 1st August 2005, 08:04 AM   #18
amo is offline amo  United States
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Hey guys, I have been chewing over the information here. Please let me know if I am too much off subject or hijacking the thread, so that if needed I will start a new one. Its just Kevin and everyone else seems to know quite a bit about the information I have been seeking so hard...

First and formost: Some time ago I found a set of regular "parallel" cables made by cooler master which incorporated a foil shield (not sure about copper mesh), and provided a drain wire so that the junk collected on the foil can be dumped to the case or other ground. I was so excited about this, and now I can not stop thinking about using this on all cables inside the PC, which means all internal power leads and SATA data links. This all would have to be DIY, but certainly simple. Will this create more problems then it will solve? Worth the time? What if I make sure to ground everything in a star pattern?

Next obssesive issue: Should I buy a huge case, and add mu-metal shielding to the motherboard, provided I take care of cooling of the critical components (besides the obveous parts like chipset and memory, I will find out what else needs to be actively cooled). At this point, I am not sure whether I would be protecting the motherboard from the system or vise versa... Of course, the PS would be in mu-metal heaven. I am hoping to replace mine with the phantom, which is totaly fanless. Then I have lots and lots of huge heatsinks I could add to the phantom, so that the sorrounding mu-metal will not interefeare with colling of the PS.

I guess mu-metal shields for the sound card and its doughter card will work well. This is already done on the high end wireless network cards by some manufacturers, although I am not sure whether they use mu-metal or some other material.

Here is the crazy part: What about isolating the metal part of all the PCI/AGP cards which are installed, from the case, only letting them be connected to the mother board through the interface. And/Or soldering a lead to the metal part of each PCI/AGP card, and grounding the ends of these leads to the same place on the case (I have been reading too many amp threads). Same for the mother board mounting. What about mounting the mobo using isolated hardware, and grougning the mobo to the case in the same place the PCI cards are gounded? In my case this is easy becasue the entire aluminum platform holding the MOBO is isolated from the case by sitting on plastic rails. Outside of "overdoing it", will this improve the horrendous conditions inside the PC?

At this point I am not going to go into all the crazy ideas for eliminating physical vibration generated by moving parts - will leave this for later. By the way, there is an interesting article about managing EMI and grounding noise in this month's issue audioXpress, using among other things, parts from a computer power supply!!! (It says that such filters are actually used inside a PC PS to prevent the PC noise from going back out to you little corner of the AC grid, messing with your other equipment!!!!! now that is something to sleep on.)
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Old 1st August 2005, 05:34 PM   #19
kevinkr is offline kevinkr  United States
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Hi Andy,
Thanks for the tip, I was already aware of this page and it is out of date, the latest version of EAC is just a little bit different. I wrote a script that seemed to work, but the process of ripping and converting seemed very slow. Ripping and then converting as a separate step seems to work a lot better.. I am using the highest quality FLAC encoding setting, and doing a verify, which makes it quite slow..

Kevin
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Old 1st August 2005, 05:50 PM   #20
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Default perhaps slightly off-topic...

This is my $79 silent PC music server. It's a Linksys NSLU2 which has been uNSLUng and clocked. The OS is Linux and I'm running a Slimserver off it. Sound quality is 1st rate.

Click the image to open in full size.

Cheers, mac.
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