Can a computer act as a preamplifier

[Aaron Fude]

Hi,

I'm looking for space saving options here. Are there sound cards that
allow you to plug in your unpowered nice spearkers directly into it?
Obviously I know very little about audio and electronics. I would hope
to be able to plug in up to three pairs of speakers.

Basically, I have a computer that's already acting as a TV/DVD player/
thermostat controller/etc (and I have backups ready to take over if
something goes wrong). Now if I could only get rid of my cdplayer,
preamplifier and the CD's, I'd be set.

Thanks!

[Mark D. Zacharias[_3_]]

"Aaron Fude" > wrote in message
...
> Hi,
>
> I'm looking for space saving options here. Are there sound cards that
> allow you to plug in your unpowered nice spearkers directly into it?
> Obviously I know very little about audio and electronics. I would hope
> to be able to plug in up to three pairs of speakers.
>
> Basically, I have a computer that's already acting as a TV/DVD player/
> thermostat controller/etc (and I have backups ready to take over if
> something goes wrong). Now if I could only get rid of my cdplayer,
> preamplifier and the CD's, I'd be set.
>
> Thanks!

Ordinary sound cards have only low powered, small amp chips suitable for
running small "computer" speakers.
I am unaware of any with larger amp chips, though this may be technically
possible, perhaps up to about 20 watts per channel.

It would not normally be possible to achieve higher power such as a modern
amp or receiver would have, since the highest internal voltage from a
computer power supply is 12 volts.

You probably need an external power amp, or powered speakers.
Another option might be a USB D/A converter feeding a power amp, but this
raises other potential issues, such as turn-on transients, what kind of
potentially harmful (very loud) noise might get to the speakers in the event
of a glitch or lockup. Such a device has no volume control, that being
totally controlled by your media player application.

I think an integrated amp with a regular volume control would be helpful to
prevent such problems from potentially damaging your speakers, and some
nicer ones have provisions for up to three sets of speakers, although you
can only run two sets at a given time. The sound card can feed the AUX or CD
input of the amp, although I would prefer a digital output from the
computer, feeding a D/A converter, and from there to the amp. Sound cards
usually have fairly mediocre analog audio output.


Mark Z.

[Arny Krueger]

"Mark D. Zacharias" > wrote in
message

> Ordinary sound cards have only low powered, small amp
> chips suitable for running small "computer" speakers.

I would put their capabilities lower than that - mostly just headphones.
Most have line-level outputs (1-2 vrms) but are designed to drive loads as
small (far higher power than regular line-level) as 16 ohms.

> I am unaware of any with larger amp chips, though this
> may be technically possible, perhaps up to about 20 watts
> per channel.

Tripath marketed a slot card that was good for maybe 8 wpc at something just
shy of hi-fi standards. I own one and it still works. I used it just lately
to drive a pair of NHT SZs.

> It would not normally be possible to achieve higher power
> such as a modern amp or receiver would have, since the
> highest internal voltage from a computer power supply is
> 12 volts.

Again agreed with the caveat that the usual switchmode power supplies used
in car audio also work in computers. Many computers have 100 watts or more
of excess capacity in their 12 volt supplies. But, some don't and even
powering up a small carsound power amp will trip out their power supplies.

> You probably need an external power amp, or powered
> speakers.

That represents close to 100% of the market.

[Richard Crowley]

"Aaron Fude" wrote ...
> I'm looking for space saving options here. Are there sound cards that
> allow you to plug in your unpowered nice spearkers directly into it?

Generally, no. A power amplifier beefy enough to drive speakers
(especially multiple pairs of speakers) draws too much power to
be able to run from the computer power supply.

> Obviously I know very little about audio and electronics. I would
> hope to be able to plug in up to three pairs of speakers.

Use powered speakers. They take up no more space than the
un-powered variety. And you said that your major concern was
saving space. Powered speakers also allow you to add as many
pair as you want without concern about overloading the source
(the computer sound card).

You mentioned "preamplifier" in your subject line, but asked
no questions about preamplifiers. A preamplifier and a power
amplifier (for speakers) are two different things.