HiFi Speakers to Computer

[Roko]

Hi all,


I'm new here, and for starters I have a really noobish question:

Why exactly is it impossible to connect HiFi Speakers to a computer (except because of the fact that they don't have a mini-jack plug :D (at least mine don't) )?

I know it's possible to connect a computer to a HiFi system (by plugging it into "Line In"/"AUX"), but I would like to be able to do it without the Hi-Fi system, only with the speakers.

I guess what I really want to know is what kind of a 'converter' is there inside the Hi-Fi system..? Does it modify the signal from the computer, or is it merely a small circuit just adapting the amperage/voltage/impedance/whatever..?


Thanks in advance

[ShadowTek]

On 2010-02-12, Roko > wrote:
>
> Hi all,
>
>
> I'm new here, and for starters I have a really noobish question:
>
> Why exactly is it impossible to connect HiFi Speakers to a computer
> (except because of the fact that they don't have a mini-jack plug :D
> (at least mine don't) )?
>
> I know it's possible to connect a computer to a HiFi system (by
> plugging it into "Line In"/"AUX"), but I would like to be able to do it
> without the Hi-Fi system, only with the speakers.
>
> I guess what I really want to know is what kind of a 'converter' is
> there inside the Hi-Fi system..?

The main value of your receiver is that it has an amplifier inside of
it, which allow you to send a respectable amount of power to the
speakers. As you may have seen before, some PC speakers *do* plug right
into the computer's audio output jack, but they aren't very good/powerful
speakers, since they aren't getting enough juice to really do anything.

[Dave Platt]

>Hi all,

>I'm new here, and for starters I have a really noobish question:
>
>Why exactly is it impossible to connect HiFi Speakers to a computer
>(except because of the fact that they don't have a mini-jack plug :D
>(at least mine don't) )?

Well, it isn't impossible. In most cases, though, you won't get
enough sound to be useful.

Loudspeakers require that a significant amount of power be delivered
to the drivers (the "speakers" themselves mounted in the cabinet) in
order to create a useful amount of sound. Typically, a HiFi speaker
is driven by an amplifier that can deliver a maximum of tens to
hundreds of watts. For most hi-fi speakers, average listening levels
run in the range of a few watts. Speakers have a relatively low
"impedance" (measured in ohms)... this means that they draw a fairly
large amount of current for any given amount of voltage. 8-ohm
speakers are quite typical. Stereo receivers and amplifiers are
designed to drive these low impedances, with enough voltage and
current to deliver their rated power.

Most computer sound-card outputs do *not* include a speaker amplifier.
They aren't designed to deliver large amounts of power, or to drive
low impedances. They are typically designed to drive efficient
headphones (drawing a fraction of a watt, at impedances of 32 ohms on
up), or to drive "line-level" devices (amplifier inputs or
"self-powered" computer loudspeakers, drawing a tiny fraction of a
watt with impedances of thousands of ohms).

In short, computer sound-card outputs are "wimpy" - they don't have
strong enough electronic "muscles" to deliver the power needed to move
a heavy loudspaker driver's cone back and forth to make sound.

Many computer loudspeakers have built-in power amplifiers, required to
boost the line-level signal and drive the computer speaker properly.

Most hi-fi loudspeakers do *not* have a built-in amplifier... there
are some exceptions, but most do not.

>I know it's possible to connect a computer to a HiFi system (by
>plugging it into "Line In"/"AUX"), but I would like to be able to do it
>without the Hi-Fi system, only with the speakers.

To do that, you'd need one of two things:

- A hi-fi speaker with a built-in amplifier (they do exist), or

- A new computer sound-card with a built-in speaker-level power
amplifier. Once again, these do exist, but they're not very common,
and typically can't deliver more than a couple of watts per
channel.

>I guess what I really want to know is what kind of a 'converter' is
>there inside the Hi-Fi system..? Does it modify the signal from the
>computer, or is it merely a small circuit just adapting the
>amperage/voltage/impedance/whatever..?

It's an active amplification stage (or several stages). It takes an
incoming signal with only a few milliwatts of power (a typical
line-level signal is 2 volts peak-to-peak into 5k ohms or so, which is
less than a thousanth of an ampere), boosts the voltage upwards by a
factor of 10 or more, and is capable of driving the speakers with
currents of several amperes. In short, the amplifier is delivering
thousands of times more power to the speaker, than it's taking in from
the computer's sound-card output.

The signal coming out of the amplifier looks like a "big brother" of
the signal going in... the waveform should have the same shape (if it
doesn't, the amp is distorting it) but it's larger in both voltage and
current.

The additional power is drawn from the building's AC power mains. Not
all of the power pulled from the mains ends up going to the speaker...
there's a significant amount of waste in most amplifier designs, and
this ends up being dissipated as the heat which warms up the amp.

--
Dave Platt > AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

[geoff]

Roko wrote:
> Hi all,
>
>
> I'm new here, and for starters I have a really noobish question:
>
> Why exactly is it impossible to connect HiFi Speakers to a computer
> (except because of the fact that they don't have a mini-jack plug :D
> (at least mine don't) )?

It isn 't impossible, but you won't hear much.

>
> I know it's possible to connect a computer to a HiFi system (by
> plugging it into "Line In"/"AUX"), but I would like to be able to do
> it without the Hi-Fi system, only with the speakers.

The 'hi-fi system' includes an amplifier, which is necessary to provide
sufficient power to make the speakers sound liud enough.

>
> I guess what I really want to know is what kind of a 'converter' is
> there inside the Hi-Fi system..? Does it modify the signal from the
> computer, or is it merely a small circuit just adapting the
> amperage/voltage/impedance/whatever..?


It amplifies the signal from a computer, CD, Tuner, DVD, turntable,
whatever, to enable the sound to be heard from speakers.


geoff

[Arny Krueger]

"Roko" > wrote in message

> Hi all,
>
>
> I'm new here, and for starters I have a really noobish
> question:
>
> Why exactly is it impossible to connect HiFi Speakers to
> a computer (except because of the fact that they don't
> have a mini-jack plug :D (at least mine don't) )?

Most computer sound cards are designed to drive headphones and speakers with
their own power amplifiers built into them.

> I know it's possible to connect a computer to a HiFi
> system (by plugging it into "Line In"/"AUX"), but I would
> like to be able to do it without the Hi-Fi system, only
> with the speakers.

This won't be sucessful.

> I guess what I really want to know is what kind of a
> 'converter' is there inside the Hi-Fi system..?

The "converter" is called a power amplifier.

> Does it
> modify the signal from the computer, or is it merely a
> small circuit just adapting the
> amperage/voltage/impedance/whatever..?

These things vary, but at the minimum they are fair-sized circuits that
adapt the amperage/voltage/impedance, as you put it. Their size is
nontrivial because of the power levels that are involved.

It turns out that most desktop PCs have fairly healthy internal 12 volt DC
power sources that have considerable reserves. Power amplifiers of the kind
that are used with automotive sound systems (which are designed for 14.7
volt power) can be adapted to exploit this source of power.

[Roko]

wow... thank you all for your replies, you've definitely answered all of my questions.
I have new ones now, of course :)

So this means I would be able to connect the HiFi speakers to the computer if I had an amplifier (of satisfactory quality) which would be put between the two? Of course, that would require some necessary tweaks and I would actually end up building a receiver? And another of course: if not building a brand new amplifier from the very beginning, I would have gotten it from another HiFi receiver, and that again would make no sense doing because the amplifier, as ShadowTek said, is the main value of a receiver and then I could have just as well connected the speakers through the existing receiver?
Sooo, if the answers to the above questions are all "yes", the only sane thing to do is to buy a new HiFi receiver - that would actually prove to be the cheapest solution then?

Once again, thank you all for your time and patience :)

[David Nebenzahl]

On 2/13/2010 2:13 PM Roko spake thus:

> wow... thank you all for your replies, you've definitely answered all of
> my questions.
> I have new ones now, of course :)
>
> So this means I would be able to connect the HiFi speakers to the
> computer if I had an amplifier (of satisfactory quality) which would be
> put between the two? Of course, that would require some necessary tweaks
> and I would actually end up building a receiver? And another of course:
> if not building a brand new amplifier from the very beginning, I would
> have gotten it from another HiFi receiver, and that again would make no
> sense doing because the amplifier, as ShadowTek said, is the main value
> of a receiver and then I could have just as well connected the speakers
> through the existing receiver?
> Sooo, if the answers to the above questions are all "yes", the only
> sane thing to do is to buy a new HiFi receiver - that would actually
> prove to be the cheapest solution then?

Yes. You're waaaaay overthinking this.

My computer is connected to my old receiver (bought used in 1975), which
provides more than adequate sound both in terms of volume and quality.
The line-level connections (line in and line out) are pretty standard
between computer sound cards and audio equipment.

Used audio receivers of sufficient quality for what you want to do are a
dime a dozen. Often you can scavenge them for free.

You don't need to "build" anything (well, except maybe a cabinet or
shelf to hold this stuff).


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"

[geoff]

Roko wrote:
> So this means I would be able to connect the HiFi speakers to the
> computer if I had an amplifier (of satisfactory quality) which would
> be put between the two? Of course, that would require some necessary
> tweaks and I would actually end up building a receiver? And another
> of course: if not building a brand new amplifier from the very
> beginning, I would have gotten it from another HiFi receiver, and
> that again would make no sense doing because the amplifier, as
> ShadowTek said, is the main value of a receiver and then I could have
> just as well connected the speakers through the existing receiver?
> Sooo, if the answers to the above questions are all "yes", the only
> sane thing to do is to buy a new HiFi receiver - that would actually
> prove to be the cheapest solution then?
>
> Once again, thank you all for your time and patience :)

Yep a new hi-fi amplifier (commonly confusingly misnamed 'receiver'), or
your old one if physically close to your computer.


geoff

[Mr.T]

"Arny Krueger" > wrote in message
...
> Most computer sound cards are designed to drive headphones and speakers
with
> their own power amplifiers built into them.

In fact not very many headphones have power amps built in, but many computer
soundcards can drive >32 ohm headphones directly.
However you are correct for speakers.

MrT.

[David Nebenzahl]

On 2/13/2010 10:17 PM geoff spake thus:

> Roko wrote:
>
>> So this means I would be able to connect the HiFi speakers to the
>> computer if I had an amplifier (of satisfactory quality) which would
>> be put between the two? Of course, that would require some necessary
>> tweaks and I would actually end up building a receiver? And another
>> of course: if not building a brand new amplifier from the very
>> beginning, I would have gotten it from another HiFi receiver, and
>> that again would make no sense doing because the amplifier, as
>> ShadowTek said, is the main value of a receiver and then I could have
>> just as well connected the speakers through the existing receiver?
>> Sooo, if the answers to the above questions are all "yes", the only
>> sane thing to do is to buy a new HiFi receiver - that would actually
>> prove to be the cheapest solution then?
>
> Yep a new hi-fi amplifier (commonly confusingly misnamed 'receiver'), or
> your old one if physically close to your computer.

Hmm; misnamed? Dunno which side of the Atlantic you're on, but over here
('Merkin), a receiver is an amplifier + tuner, to distinguish it from an
amplifier, which normally lacks a tuner. (And of course, speaking of
confusion, the amplifier actually consists of a preamplifier + a power
amplifier, which are sometimes separate things ...)


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"

[Mr.T]

"David Nebenzahl" > wrote in message
.com...
> Hmm; misnamed? Dunno which side of the Atlantic you're on, but over here
> ('Merkin), a receiver is an amplifier + tuner, to distinguish it from an
> amplifier, which normally lacks a tuner. (And of course, speaking of
> confusion, the amplifier actually consists of a preamplifier + a power
> amplifier, which are sometimes separate things ...)

And a pre+power amplifier in one box is commonly called an integrated
amplifier for that reason, and a separate pre-amp or power amp are almost
always named as such.
Just to add to your list, a phono pre-amp may be separate as well, and a
moving coil cartridge pre-amp is sometimes called a pre-preamp.

MrT.

[Roko]

OK, since my mother tongue is not English (of any "kind", no matter what side of any ocean from) and since I'm a noob when it comes to HiFi, help me understand this:

Picture 1: http://www.audio-video.com.hr/img/productImages/kenwood/6300s.jpg - a HiFi *receiver*? (which I referred to as a "HiFi system" in my first post up there. (a "HiFi system" would be a receiver+speakers?))

Picture 2: http://www.quasarelectronics.com/images/electronic-kit/3050.jpg - a HiFi *amplifier*?
You say I could get one of these easily, and for a fair price? Would it be everything I needed if I just wanted to connect passive speakers (which I already have) to the computer?

[Don Pearce[_3_]]

On Sun, 14 Feb 2010 16:54:11 +0000, Roko
> wrote:

>
>OK, since my mother tongue is not English (of any "kind", no matter what
>side of any ocean from) and since I'm a noob when it comes to HiFi, help
>me understand this:
>
>Picture 1:
>http://www.audio-video.com.hr/img/productImages/kenwood/6300s.jpg - a
>HiFi *receiver*? (which I referred to as a "HiFi system" in my first
>post up there. (a "HiFi system" would be a receiver+speakers?))
>
>Picture 2:
>http://www.quasarelectronics.com/images/electronic-kit/3050.jpg - a
>HiFi *amplifier*?
>You say I could get one of these easily, and for a fair price? Would it
>be everything I needed if I just wanted to connect passive speakers
>(which I already have) to the computer?

Fine with the first, but for the second you will probably want
something in a case, with mains power, like the first (but without the
radio part). Ebay is your friend.

d

[Dave Platt]

>OK, since my mother tongue is not English (of any "kind", no matter what
>side of any ocean from) and since I'm a noob when it comes to HiFi, help
>me understand this:
>
>Picture 1:
>http://www.audio-video.com.hr/img/productImages/kenwood/6300s.jpg - a
>HiFi *receiver*? (which I referred to as a "HiFi system" in my first
>post up there. (a "HiFi system" would be a receiver+speakers?))

Yes, that looks like a typical hi-fi or A/V receiver. It has the
preamplifier, probably an FM tuner, and multiple amplifier sections.
Since its display says "6CH" I'd guess it's a home-theatre model, with
perhaps as many as six amplification channels. You only need two
channels, so this would be "overkill" for your application.

>Picture 2:
>http://www.quasarelectronics.com/images/electronic-kit/3050.jpg - a
>HiFi *amplifier*?
>You say I could get one of these easily, and for a fair price? Would it
>be everything I needed if I just wanted to connect passive speakers
>(which I already have) to the computer?

This little module looks as if it's just part of the power supply, not
the amplifier itself.

On the http://www.quasarelectronics.com/audio-amplifiers.htm page,
look under "stereo audio amplifier modules". One of the modules that
has somewhere between 10 and 25 watts per channel would probably be
adequate for what you need. You'd need to provide a power supply, as
well.

I agree with what other people have suggested: go find yourself a
used stereo audio amplifier or receiver. Simple stereo receivers are
very easy to find on the used market: a lot of people have upgraded
their homes to have many-channel "home theatre" receivers or
amplifiers, and the older two-channels stereo receivers are no longer
needed.

I don't know where you live, but around here (California) one can walk
into any thrift store (charity-donation shop) and find a bunch of
older stereo amplifiers or receivers that have simply been given away
by their owners, and are being sold to raise money for charity. If
you go around a residential neighborhood on a nice weekend, you'll
usually find people running "garage sales", and finding a used
receiver at one of these is a very common thing.

Buying a used stereo receiver is probably going to be both the
easiest, and least expensive solution to your problem.

The only reasons I'd see for building up a dedicated amplifier-only
solution from a kit or from modules, would be if you want the
experience of doing the electronic assembly, or you have some
restriction on the installation (e.g. it must fit into a certain
space) which simply can't be met by a full-size receiver.

Just buying a ten-watt stereo amplifier module and a power supply
would probably cost you more than a used receiver with considerably
more power.

--
Dave Platt > AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

[Richard Crowley]

"Roko" wrote ...
> OK, since my mother tongue is not English (of any "kind", no matter what
> side of any ocean from) and since I'm a noob when it comes to HiFi, help
> me understand this:
>
> Picture 1:
> http://www.audio-video.com.hr/img/productImages/kenwood/6300s.jpg - a
> HiFi *receiver*? (which I referred to as a "HiFi system" in my first
> post up there. (a "HiFi system" would be a receiver+speakers?))

Yes that is a typical "receiver" (power amplifier and radio tuner and
input selector and volume/tone controls). That is what most of us are
recommending for your computer. In most places here in the US,
older discarded receivers are available for free or almost free.

> Picture 2:
> http://www.quasarelectronics.com/images/electronic-kit/3050.jpg - a
> HiFi *amplifier*?
> You say I could get one of these easily, and for a fair price? Would it
> be everything I needed if I just wanted to connect passive speakers
> (which I already have) to the computer?

That is an example of an amplifier module kit. There are perhaps 100
different kinds of those amplifier module kits available online. They
are perfectly adequate for your computer speakers, but they would
require assembly, power supply, enclosure, connectors, etc. A fun
project if that is what you are interested in. Else it is certainly faster
and cheaper to just find an old receiver.

[Roko]

Thanks to everyone.

I've found a receiver+speakers on an online auction site with the starting bid of only 1kn, which would be $ 0.1864 according to google :D
It's funny that the receiver is exactly the same as my old one, so I know I'll be satisfied with it. The cassette and CD players don't work, but I wasn't looking for that anyway :) The girl says that the fm/am radio is the only thing that works on the receiver, and I guess that means that the amplifier inside is obviously alive, if sound is able to come out of the speakers... The only thing I have to hope for is that the line-in connections are fine, which is more than probable, isn't it?

Oh, and she also says her dog chew up an edge of one of the speakers :D here's the pic: http://www.aukcije.hr/uploaded_new/28706/953570/original/20100214133254.jpg

Now I only have to wait for 8 days, and it's mine. For 20 cents if no one offers more. :P And then disinfect...everything. Bloody barker.

Thank you all and I apologise for any grammatical/logical/spelling errors I may have made in the topic. I'm from Croatia, and every correction is more than welcome. Let's make mistakes useful :D

[Hank]

In article >,
Roko > wrote:
>
>OK, since my mother tongue is not English (of any "kind", no matter what
>side of any ocean from) and since I'm a noob when it comes to HiFi, help
>me understand this:
>
>Picture 1:
>http://www.audio-video.com.hr/img/productImages/kenwood/6300s.jpg - a
>HiFi *receiver*? (which I referred to as a "HiFi system" in my first
>post up there. (a "HiFi system" would be a receiver+speakers?))
>
From the looks of the picture, this appears to be what I'd call an
"integrated amplifier." That is, it has switchable inputs for several
signal sources, a volume control in a "preamplifier" section, followed
by a power amplifier. It does not, so far as I can see, have a radio
receiver section for either AM or FM. It will have a "tuner" input so
that you can connect the audio output of a separate tuner to it.

A similar box that does have a radio receiver in it in addition to the
preamplifier and power amplifier is generally termed a "receiver"

Properly used, "Stereo" refers to two-channel vs. "Monaural," or one
channel. and "Hi-Fi" is short for "high fidelity," or a (relatively)
wide audio frequency bandpass from input to output. Human hearing
runs from about 20 Hz at the low frequency end to about 20 Khz at the
high end, but a lot of "hi-fi" audio equipment, particularly in
earlier years (1935-55) had narrower bandpass. For reference, the
Disney movie "Fantasia" in 1939 specified 10 Khz (kilocycles) as the
high frequency that theatre audio had to pass to show the movie.
And, even today, low frequency cutoff can be as high as 40 or 50 Hz.
in audio equipment.

>Picture 2:
>http://www.quasarelectronics.com/images/electronic-kit/3050.jpg - a
>HiFi *amplifier*?
>You say I could get one of these easily, and for a fair price? Would it
>be everything I needed if I just wanted to connect passive speakers
>(which I already have) to the computer?
>
A kit like that, you can if you want to. That is not the way I would
go for connecting computer sound outputs through an 2-channel amplifier
to a pair of loudspeakers.

What I am actually using on my computer equipment is an old used
Kenwood, marked on the front panel "Kenwood stereo integrated
amplifier KA-32B." Can't remember now when or where I got it,
probably $10 at a yard sale or pawn shop 15-20 years ago. The
speakers are ancient Technics SB-2F, very small bookshelf speakers
that fit nicely on either side of the monitor. The computer line out
jack connects to the amplifier tuner input through a 3.5 mm to 2 RCA
plug cord. The speakers were $1 at a farm auction.

You can buy new speakers with built-in amplifiers for computer sound,
but I used cheap stuff from ca. 1970 that I already had. You probably
can find similar items at yard sales, second hand stores, pawn shops
for a lot less money than buying new. And it works extremely well.

To see how this equipment is classified, you can go to the Audio
Classics (Binghamton, NY) web site:
http://www.audioclassics.com/
They sell a lot of used good equipment and some new, none of it
"cheap" (low quality for low price) or "inexpensive" (just low price).
Much of my main audio system equipment came from there: a McIntosh
C-28 preamplifier and a McIntosh MC-2125 power amplifier driving
Klipsch Cornwall speakers.

Hank