HTPC instead of Pre-amp

[mangrovia]

If you have a media center pc with a good sound card, why would one need a pre-amp? If receivers are essentially digital-to-analog converters and source splitters, couldn't a computer do the same thing?

From what I have seen, upper end 8-channel pre-amps (costing around ~$3k-$5k) deliver nearly the same 24b/192khz digital-to-analog conversion as a sound card costing $250 or less.

If all your audio is coming from your computer anyway can't you just bypass a pre-amp or receiver and plug directly into a power amplifier?

I've read that volume spikes out of a computer could potentially damage an amplifier, but couldn't fuzes protect equipment from this? Are there other factors that should be considered when sending computer audio directly to an amp?

To me the concept sound like heresy, but maybe it's worth consideration. I'm no expert on this, so I'd honestly love to hear all perspectives.

Thanks

 

[OttoMatic]

If all your audio is coming from your computer anyway can't you just bypass a pre-amp or receiver and plug directly into a power amplifier?

You can certainly do that if you want.

I've read that volume spikes out of a computer could potentially damage an amplifier, but couldn't fuzes protect equipment from this? Are there other factors that should be considered when sending computer audio directly to an amp?

Not sure about "volume spikes". As long as you have a good method of controlling the PC's output volume, you should be fine.

Try it!

 

[JCW]

I'm not sure if the output from a PC is strong enough to drive a power amp properly, but it sure wouldn't take long to find out. If the PC output is too weak, you'd have a signal to noise ratio issue. You can check the specs of your PC and poweramp before you try it.

I would plug it up and set the PC volume somewhere around the 1/4 to midpoint and begin with the power amp volume off and ease it up. If it distorts, it's obviously too much drive from the PC. If it's weak and noisy, it's obviously too little drive from the PC. If it's perfect, congratulations.

One other issue would be the lack of tone controls (unless you can adjust the tone on your PC adequately with something like Cool Edit Pro, or have an inline EQ).

Don't take my word for it, but that's my 2 cents worth anyway.

Cool idea!

 

[OttoMatic]

Well, I guess I didn't mention that I've been using an HTPC for several years now. I'm sure that the sound card signal level is strong enough to drive your amp. It's essentially the same as setting the preamp's volume to 0dB (no gain, no attenuation, if they implemented it right). You can do EQ in programs like Winamp, at least for music playback. I think some of the movie playback software will also do some EQ, but I've never used it (TotalMedia Theater is my new favorite movie player).

I still use a preamp between my PC and the amp for a number of reasons, but it's not necessary if you don't want it. I happen to feed it a digital signal, so, yes, you'd have to go analog out of your PC, but I think you know that. You noted sound cards in the $250 range, and I would consider that an upper end sound card. I would not expect a top end sound card to have low SNR, though the on-board audio on my Dell most certainly does (it probably cost $5 or $10 to put that on the board, so it's no surprise that it's noisy). But it should be easy to find a sound card that doesn't have low quality or low SNR.

I feed the on-board analog audio on my new Gigabyte motherboard, to a second zone receiver that powers a set of speakers in my family room and a pair on the patio. I have no problems with that setup, but it's not for critical listening -- I don't notice any SNR issues, but I bet they are there.

Good luck!

 

[mangrovia]

Thanks for the advice.

My sound card has an alleged 120 dB SNR, but I've never actually hooked it up into a dedicated power amplifier. I currently run digital signal into my receiver/amp. When I get a new amp, I'll have to try it all out an see if I need a processor in addition.

I am now optimistic about the whole process, so thank you.

And yes, TMT is great.