PC as preamp

This will work, but it can be dangerous. If for any reason the levels on the computer go up to full, you're looking at a BOOM somewhere.

Also, if you use the volume control in Windows you are really degrading your sound output.

Yes, and yes. Depending on your PC you may not get the .1 sub channel, just a summed mono channel.

Most soundcards (and even onboard) are multichannel.

They generally go (for many onboard)

Green: Front L/R
Blue: Rear L/R
Orange: Center/Sub

Or something of that ilk.. anyway, get a set of 8Ohm to RCA cables for each one (stereo, headphone jack to RCA) and you're set.

Two things:
1. loss of information
2. digital attenuation often does nothing to the noise level, so you can get greater noise level after you amplify

Sadly, computers are far too noisy, and you will rarely get good SNR from a computer analog out. Optical out is best when dealing with computers.

If you must go analog, try an external USB sound card.

It is a digital volume control and cuts bit resolution to lower volume.

A HTPC should be viewed as a component in a home theater system and not the controller. You could use the HTPC as a controller but then you are severely limited in what you can do with it. A standalone preamp/processor will always do a better job of controlling the audio and video. It will also allow you to add more components into the mix, like a standalone Blu-Ray player or Tivo. PCs do not have auxiliary inputs for adding external A/V devices aside from USB ports or similar interfaces.

You should be completely fine just using stereo to RCA adapters to hook up your amp to your computer.

I use my computer as source/controller to output sound to my Stereo receivers, which basically just are used as amps anyway.

I've set the volume on the receiver at a 'good' level and then control it through computer volume setting.

As some have mentioned it isn't maybe the most 'optimal' solution but I bet to say that you will just be fine with it like this unless you really have high calibre gear that really requires the best in all parts and the ears to go after the finest details.

I have just plain budget stuff in my audio. I have only spent enough money for a single 3.5mm stereo -> RCA adapter, rest I scavenged about from unused items laying about the house.

But I caution you to be careful with volume if that amp doesn't have a volume dial of it's own. It can get quite load quickly I think if you only can set it through your computer.

I'm no expert, but I've been using my HTPC as a preamp for almost 10 years. I've always used a sound card. I've gone through a couple of M-audio cards and now use an Asus HDAV deluxe (I wanted the RCA out). I use the RCA out straight to an ATI 1506 amp. The M-audio cards would send a nice "pop" when the computer turned on (so order ws important when turning on the electronics). The Asus doesn't have that problem. Some people have complained about driver support though. I have't used a hgh end pre-amp, so I can't compare, but what I have sounds pretty good to me.

It can be done, but it's less than the ideal setup. I've been an audiophile for over 45 years and I find the thought of using a PC as an audio preamp completely repugnant. I can't help it if I'm picky about what I listen to. OTOH, if the sound suits you then go with what you like. Just don't try a separate high-end preamp, because it might change your mind.

I'd recommend a nice sound card - then that sound card acts like the pre-amp. Of course for the price of nice sound card you might be able to get a used pre-amp..

Some of the nicer sound cards (like ASUS) have some shielding on them which seems to help with the noise level as compared to on board sound. With sound cards you can often get some pretty nice DACs compared to what you would pay for a seperate unit. So it absolutely can work.

I think the poster that talked about how computers are a "noisy" enviroment electronically is correct and this is why onboard sound seems to suck despite being excellent 'spec wise' in my experience.

Of course you can take the next step and buy an external sound card (but then again that is pretty much the same as a pre-amp)..

Pete

the biggest thing to remember when doing this, is the volume control problem.

when you tell the computer to output sound at half volume, it isnt lowering the gain of the sound card, it is lowering the dynamic range of the sound going to it. therefore, when outputting sound at 50%, you are really compressing the full sound into the lower half the volume range it previously occupied. this is essentially throwing away half the information. in the sound.
go down to 25%, and you are throwing away another half. a good way to think of it is whatever the windows mixer percentage shows, thats how much of the original dynamic range you are keeping.

In Vista/Windows 7, all audio is converted to floating-point so there is no loss of information with a digital volume control.

Dynamic range is decreased with all volume controls, not just digital. The loudest gets smaller, the quietest stays the same.

Good blog post explaining it all, from the head of the audio team at MS: http://blogs.msdn.com/b/larryosterma...is-volume.aspx

To the OP: you should have no issues doing what you want to do. Just look up what ports output what for your soundcard.

The others have made it pretty clear. It's not the greatest idea use use the PC analog out as a source. They are usually quite noisy. While you can buy sound cards that are much better in SNR, you will find that you still need an external 6 channel preamp.

The center/sub output is stereo. The signals are split down the connector. If you get a mini jack to RCA out connector, one RCA will be your Center and the other will be the Sub.

Not many people go this route for those reasons.

So basically, yes, you can use the PC analog as a source.
It is more expensive and requires more external components.
Using the PC as a preamp is out of the question for the various reasons listed above. It is a source that requires a preamp.

Even onboard sound cards today have extremely low noise, in the 100-120dB SNR range. Not ultra high-end, but not the 70-80dB noisy chips of 10 years ago.

The nay-sayers would be well served to peruse the older threads on these same subjects... particularly the Auzen Meridian card and the X-FI Elite Pro, as well as the newer Asus cards, starting with the HDAV 1.3. The outputs from these cards, direct to power amps, exceed a majority of the low and mid range AVR's. You can buy an E-mu 1616m and blow away a lot of the higher end AVR's.

I'm still using my Auzentech Merdian to drive my Aragon Palladium monoblocks. Its been 5-6 years, maybe more.