Legacy PCI card: How clean can I make its digital audio output signal?

[chane]

My next pc build (Would you believe Windows XP Pro SP2 32 bit?) will be a lower power desktop dedicated to audio. I'll use it for editing and adding effects to wav files of my CD track rips. Then SPDIF or USB will feed my external DAC to serve my amps and speakers. But I have these questions regarding the ultimate vulnerability of the digital audio signal before and after leaving my pc:

1.) Would it be true that the faster the CPU and/or the higher its TPD, the more RFI and EMI radiation it and/or the pc's switched mode supply will generate?

My CPU will be something like this http://ark.intel.com/products/52275 As you can see, it has a stock 2.4GHz speed and 45w TPD. Does that make it a "safer" choice than a 4GHz 80w CPU to insure digital audio signal quality?



2.) I need to switch between using two DAW platforms, this one http://pro.**********/en/samplitude/overview.459.html http://pro.**********/en/samplitude/technical-data.484.html and Pro Tools 7.4.2. , the latter runs only with XP 32 bit.
I need this old PT version to run a valuable and expensive plug-in. However PT needs an old M-Audio PCI card (with on board proprietary drivers) to run at all http://m-audio.com/products/en_us/Audiophile2496.html This card does have a SPDIF output. But unlike this USB card http://jplay.eu/jcat/ that can run off a battery supply, this PCI card must run off the pc’s SMP supply, of course. Thus, would digital audio signal quality from the M-Audio card’s SPDIF output be more at risk than that from the battery powered JCAT card’s USB output?

3.) With PCI long since supplanted by PCIe, I’m one of the unfortunates needing a motherboard with native PCI support-which have now dwindled down to very few
http://en.wikipedia.org/wiki/List_of_Intel_chipsets#LGA_1155

But at least there’s a board like this one
http://www.asus.com/us/Motherboards/P8Q77MCSM/ However, if digital audio signal quality from the M-audio card is more at risk than

it is from the JCAT USB card, would the RF and EMI suppression
circuitry in this motherboard http://www.asus.com/us/Motherboards/P8Q77MCSM/ be just as good as in this one http://www.asus.com/us/Motherboards/Z97MPLUS/ ??

(Btw, despite the PCI slot in the latter board, it does NOT offer native PCI support, only via the PCIe bus)


4.) Lastly, despite the cost, has anyone had any experience with using linear power supplies to drive their pcs or macs? If so, is there a very definite sound quality boost with the LPS installed compared to that of the SM supply? Enough to justify the cost?



(Note, by sound quality, I mean better sound from the output of

your external DAC fed from your computer-not any analog audio

from the motherboard or sound card).


If yes, did you get the LPS from here http://www.coreaudiotechnology.com/kaia-linear-power-supply/ ?
Or here http://www.paulhynesdesign.com/ ?

 

[bryanl]

1.) Would it be true that the faster the CPU and/or the higher its TPD, the more RFI and EMI radiation it and/or the pc's switched mode supply will generate?

It depends, but don't hold me to that opinion.

You probably don't remember the cheap clones of the first IBM PC motherboards, made with only two layers of copper, but they would cause far more audio, radio and TV interference than any 4-6 layer motherboard equipped with a 1 GHz CPU. In addition, newer motherboards rely heavily on differential transmission of signals, which should reduce emissions further, and higher frequencies are easier to filter from audio frequencies.

My CPU will be something like this http://ark.intel.com/products/52275 As you can see, it has a stock 2.4GHz speed and 45w TPD. Does that make it a "safer" choice than a 4GHz 80w CPU to insure digital audio signal quality?

4.) Lastly, despite the cost, has anyone had any experience with using linear power supplies to drive their pcs or macs? If so, is there a very definite sound quality boost with the LPS installed compared to that of the SM supply? Enough to justify the cost?

(Note, by sound quality, I mean better sound from the output of your external DAC fed from your computer-not any analog audio from the motherboard or sound card).

Engineers doing analog development work still use linear power supplies so they don't have to worry if any problems are caused by supply noise pickup, but a linear supply for a PC merely exploits ignorant, highly suggestible fools who think they really can hear a difference between zip cord and $1000 speaker cables. Noise rejection of even modestly priced sound cards running inside an environment full of RF and digital noise is now commonly 90dB, compared to the 35 dB of some old 2-layer ISA sound cards.

 

[richaron]

Basically... Every digital signal (like SPDIF), from every device, from every price range, connected to any other electrical devices, will contain exactly the same information*. Regardless of the noise.

*unless devices aren't compliant (very rare), or "noise" is higher than signal (it wont be).

 

[inachu]

Depends on how well shielded the sound card is.
I am researching this myself as I just purchased a pc to be my D.A.W.
Also bought a mixer and the blue yeti microphone. Will need to buy XLR cables and mic.

So I am also for the time being doing this via PCI. props on making this thread.

 

[Billb2]

Basically... Every digital signal (like SPDIF), from every device, from every price range, connected to any other electrical devices, will contain exactly the same information*. Regardless of the noise.

*unless devices aren't compliant (very rare), or "noise" is higher than signal (it wont be).

Aw, cumon. Your statement, while debatable, isn't germane to the OP's question. The "distortion" happens during the analogue to digital and digital to analogue conversions, or anywhere else in a computer where analogue signals run through wires. That's where RF and EMF are factors.

 

[Billb2]

Re: Linear power supply for DAW.
The audiophiles are doing it.
Core Audio Technology

 

[inachu]

To the OP maybe you might need something like this to convert and manage settings:

http://www.asio4all.com/

 

[chane]

To the OP maybe you might need something like this to convert and manage settings:

http://www.asio4all.com/

I don't get it. Why you think that these drivers would help? You mean the drivers that Pro Tools 7.4.2. needs? If only they were available-anywhere
else but on that M-Audio card! But no way. Avid and/or M-Audio clearly have no intention of ever doing that. So I'm stuck with having to use that
card if I want to run Pro Tools.

 

[oynaz]

Re: Linear power supply for DAW.
The audiophiles are doing it.
Core Audio Technology

Then it is probably bullshit ;-)

 

[oynaz]

@chane

Take a deep breath. Yes, The PC version of Pro Tools were coded by a bunch of incompetent hacks, and I can understand why you get all riled up, but grab yourself a cup of coffee and look on the bright side ;-)
(I don't mean to be condescending, Pro Tools have messed with my head as well)

To your questions:
1a) Perhaps, but the effect will be so tiny as to have no effect on you.
2a) No. CPU choice have no effect on audio quality.
2) Stop worrying about the quality of the digital audio signal. The whole point of digital signals is that they do not degrade in quality. They work or they do not work. In the case of SPDIF, noise is a non-issue, unless you do something unspeakable with the cables - and the power supply to the sound card are completely unimportant.
3) Stop worrying about RF and EMI suppression, unless you work in an incredibly noisy environment.
4) I have not tried it, but I will bet a blowjob and a big ice cream sandwich that the answers are No and No.

In short: Stop worrying about the quality of the power supply, as long as you stay away from complete crap. It will not affect sound quality, at least not compared to literally everything else going on in your chain.
You might want an UPS or surge protector, though, but that is to protect your equipment and to prevent data loss.

 

[inachu]

@chane

Take a deep breath. Yes, The PC version of Pro Tools were coded by a bunch of incompetent hacks, and I can understand why you get all riled up, but grab yourself a cup of coffee and look on the bright side ;-)
(I don't mean to be condescending, Pro Tools have messed with my head as well)

To your questions:
1a) Perhaps, but the effect will be so tiny as to have no effect on you.
2a) No. CPU choice have no effect on audio quality.
2) Stop worrying about the quality of the digital audio signal. The whole point of digital signals is that they do not degrade in quality. They work or they do not work. In the case of SPDIF, noise is a non-issue, unless you do something unspeakable with the cables - and the power supply to the sound card are completely unimportant.
3) Stop worrying about RF and EMI suppression, unless you work in an incredibly noisy environment.
4) I have not tried it, but I will bet a blowjob and a big ice cream sandwich that the answers are No and No.

In short: Stop worrying about the quality of the power supply, as long as you stay away from complete crap. It will not affect sound quality, at least not compared to literally everything else going on in your chain.
You might want an UPS or surge protector, though, but that is to protect your equipment and to prevent data loss.

I agree when something that is supposed to be so great such as pro tools.

a good example is SOLARWINDS. It is a network diagnostic predictive downtime tool that was originally named Q from a company in Bethesda Maryland.

I am pretty sure the lead programmer is still at solar winds and complete weirdo idiot. Thousands of companies use this tool but they do not know who they are dealing with as a person. That so called smart programmer spoke aloud to the company in the one room we were in and he said he was going on a food run and to write down and give him money for the food.

2 hours later he came back.... no food and no money. He said the cashier at the counter at mcdonalds gave him bad vibes so he refused the food and money.

To this day he still owes me $7

 

[imagoon]

I agree when something that is supposed to be so great such as pro tools.

a good example is SOLARWINDS. It is a network diagnostic predictive downtime tool that was originally named Q from a company in Bethesda Maryland.

I am pretty sure the lead programmer is still at solar winds and complete weirdo idiot. Thousands of companies use this tool but they do not know who they are dealing with as a person. That so called smart programmer spoke aloud to the company in the one room we were in and he said he was going on a food run and to write down and give him money for the food.

2 hours later he came back.... no food and no money. He said the cashier at the counter at mcdonalds gave him bad vibes so he refused the food and money.

To this day he still owes me $7

You do know that Solarwinds is a company and not an application right?

--edit--

I also agree that the electrical noise only (barely) matters for analog audio. Since SPDIF is listed as the input and output and the OP specifically says digital, the computer power is non-relevant.

 

[Cerb]

Then it is probably bullshit ;-)

Probably? After the main PSU, almost anything not running directly from 12V, 5V, or 3.3V will have its own switcher.

1. No, and what issues there may be are only an issue for internal analog audio, and differential internal audio could probably work out great, even then.

2. No. A transformer-based receiver, if the SDPIF output isn't on a transformer, could reduce the chances of ground noise coupling to whatever it's plugged into, though. That's only worth even looking at if there is an analog audio problem using SPDIF from the PC but not another device.

3. There are still many PCI-equipped motherboards, for brand new CPUs. Not a problem. XP support is what you need to focus on.

4. No. If you have any SPDIF issues, the SPDIF cable and receiver (possibly part of the DAC) are where to look, not PSUs (you can't change the SPDIF transmitter, obviously). Can noise/jitter be a problem? Sure. That's why you might not want to use something from 1990 in a normal environment, today, with SMPSes all around, cell phones, wifi, etc.. The engineers making the chips that go into digital audio devices, and the implementers making the products you actually buy, are aware, and are designing accordingly, so that your fugly SPDIF input signal gets turned into a perfect I2S signal on the other side of the chip.

Leave the fancy PSU business, and EMI/RFI worries, mostly to the analog side of things.

 

[chane]

Thanks to all for comments and advice. Cerb, I have nearly enough electronics circuit knowledge to get your answers to each of my concerns. I'm stuck with using that old M-Audio card since I still want to run Pro Tools and this cool plugin http://serato.com/pitchntime.

But the DACs I'll be choosing among are fairly high end (>$5K), so I'm hoping they can clean up any jitter and clocking issues from the card's SPDIF output.

It's also a big relief to know the digital audio signal inside the pc is unaffected by the SMPS's EMI and RF. So the claim that unless one swaps out their computer's SMPS for a linear PS their digital audio will be too "dirty" is simply nonsense. Science trumps salesmanship once again.

 

[chane]

Thanks to all for comments and advice. Cerb, I have nearly enough electronics circuit knowledge to make sense of your answers to each of my concerns. Btw, ASUS Tech Support confirmed that this PCI friendly motherboard http://www.asus.com/us/Motherboards/P8Q77MCSM/ does support Windows XP 32 bit version-which I need for Pro Tools 7.4.2. Of course, I'm stuck with using that old M-Audio card since
I still want to run Pro Tools and this cool plugin http://serato.com/pitchntime.

But the DACs I'll be choosing among are fairly high end (>$4.5K), so I'm hoping they can clean up any
jitter, bit slip or clock drift that might be at the card's SPDIF output.

It's also a big relief knowing that the digital audio signal inside the pc is unaffected by the SMPS's EMI and RF. So the claim that unless one swaps out their computer's SMPS for a linear PS their digital audio will be too "dirty" for proper conversion is simply nonsense. Science trumps "creative marketing" once again.

 

[oynaz]

I still want to run Pro Tools and this cool plugin http://serato.com/pitchntime.

Glad we could be of help.
You might want to check if that plugin is even necessary anymore. Many modern DAWs have something similar build in, and while specialized hardware was needed to do the massive calculations just a few years ago, modern CPUs should make mincemeat of them.
I do not know if that is any help in your use case, but it is worth keeping in mind.

 

[mindless1]

Probably? After the main PSU, almost anything not running directly from 12V, 5V, or 3.3V will have its own switcher.

Usually yes but audio is an exception. Many audio circuits still use linear regulation, without much fuss since it's only a few dozen mA at most.

Leave the fancy PSU business, and EMI/RFI worries, mostly to the analog side of things.

Yes the analog (capability) side is why they use linear.

 

[Cerb]

Usually yes but audio is an exception. Many audio circuits still use linear regulation, without much fuss since it's only a few dozen mA at most.

That's not what I mean. Your PSU is a SMPS, then your RAM, CPU, PCH, GPU, and anything else needing different voltages, gets a switcher, too. All of that noise goes right back out to the ground (common), and anything nearby could get induced noise. Having the main ATX PSU be linear doesn't rid you of SMPS issues, and quality units have low enough and fast enough ripple that, without the rest of the PC involved, they would probably be fine for analog audio.

If good linear PSUs were used in the PC after the main PSU, then an all-linear setup might be able to provide a stable ground (common). But, there's going to be high frequency noise in there, including all over the ground, due to the voltage regulation right on the motherboard, and the constant load changes from all the power saving tech of recent years.