what do i need, pc to home theater spkrs

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I'm buying a sound card for my computer that has 4 minijack outputs (8 ananlogue outs) on it, and I want to hook these up to some home theater speakers. So i'm trying to figure out what i would need to do it. I could use a new dd ex, dts receiver to do it but they are expensive and i don't need the decoding that these receivers offer since the card already does both. All i really need is a way to connect to the home theater speakers. It seems this would be cheap to do as all i'm really doing is upping the power from the line level of the sound card to speaker level. Saying that these are just suppositions, what do you guys think? If not something retail i can buy is there a DIY project for this?

chris (TheTurtle)
 
It's not a minijack to speaker wire converter, you need a power amplifier. The sound card outputs might be able to power small (personal stereo) speakers (I don't know which sound card you have, older sound blasters could do this) but you almost certainly need more power.

You could simply build 6 DIY amplifier projects. It's what I'm doing, but frankly buying a reciever (even a good one) would be cheaper.

If you are playing DVD's, you should check out PowerDVD; it does DTS, Dolby decoding in software. The cards may offer some decoding, but PowerDVD is licensed for DTS.
 
I´d say it depends on the power you need for each channel.
If it´s mentioned "only" for PC I´d use some integrated IC.
There was a project published by Elektor magazine called "Surround sound amplifier" in Nov/01.
It uses quad channel amplifier TDA7370.
They put everything on a tiny board and in one of the PC slots on the back. Supply voltage came from the PC(12V).
I only got the article in german but maybe you get it somewhere else if you´re interested.
But this way you only get about 3W into 4Ohms and 1,5W into 8Ohms. The commercial PC surround systems usually can´t deliver more than that.
 
"If it´s mentioned "only" for PC I´d use some integrated IC"
I'm not sure what you meant by this, pc speakers are usually powered.

I'm kinda dishearted by the reply, you think this would cost more than a receiver? I was thinking it would take more time but not more money to do. I have posted a few other posts on other forums and I think this one wasn't clear on the decoding part, the card is a Hercules Fortissimo card. IF your not familiar with it it has 8 analogue outputs for 7.1 and dd 5.1 + dd ex decoding. Can I just rip the amp out of an old receiver for the setup? :)
Moving on tho, I'm a dumb newb, how do you decide what sort of amp you need by looking at the speakers. Also what diy projects are recommended.


chris(TheTurtle)
 
diyAudio Senior Member
Joined 2002
HT FROM PC.

Hi,

Hmmm,it even rimes.

Could you tell us what kind of speakers you want to hook up. (most you find in PC shops already have amplification built in)

Are you going for the common L+R +CenterChannel Sub?
(2.1)

Or the 5.1 or whatever else is there.

In case you're using passive speakers you're going to need one stereo amp for the front speakers and subwoofer.
And another amp for rear speakers and so on.

I've no idea wheter your soundcard has sufficient amplification built in but I would doubt it.

Cheers,;)
 
If it´s mentioned "only" for PC I´d use some integrated IC.

Ok. Sorry that was not so clear.
I meant actually the "typical" PC speaker setup.
Little speakers standing in the near distance to your PC so that the mentioned power levels are sufficient.
If you wanna use the surround setup for your hifi as well and so the speakers have higher distance to the listener you should think about something more "serious" so a little more power.
(which depends on speaker sensitivity as well)

I for example own cheap stereo PC speakers standing just in front of me.Rated at 240W power peaks. :Pinoc:
Built in power amplifier with TDA2030.
For the PC this just works well. If I need more (listen to the CD spin very loud) I plug in my headphones.

I thought about a more serious setup for PC for a while likewise.
But I´m just happy with how it is and think it´s better to separate hifi and PC.
The only thing I built for PC is a good headphone amplifier which is nice to have sometimes.

Jens
 
well the pc is going to be a desktop and sitting on top of my dishnetwork box and all that so it's going to be my audio output for the home theater. It is going to be driving 5.1 home made speakers by me, which i haven't built yet or decided what i'm building.

"In case you're using passive speakers you're going to need one stereo amp for the front speakers and subwoofer.
And another amp for rear speakers and so on."

I figured i would need an amp for each channel. I was recommended on another thread the gainclone. OR is that what you meant, recommend?

chris(theTurtle)
 
The typical gainclone amplifiers talked about here on this forum are mostly single channel amplifiers like LM3886,LM3875,TDA7293.
They have power ratings from 50-100W depending on supply voltage.
In your case I wouldn´t bother with those cause you won´t nearly need that much power.
That´s why I´d suggest a multi-channel IC like TDA7370.
There are much more on the market though.
Just go to the homepage of National Semiconductors or Philips and browse through the audio ic´s.

Jens
 
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