I want to build an amplifier for listening music on my computer.
Can anyone suggest where to start? I have very basic knowledge of
electronics but probably need some theory. Any good books?

I searched around on the net and the only thing I can find are complete
schematics and books on how to build tube amplifiers. I'm really not
intersted in tube amps, but since the only information on the net is
about tube amps I dont even know what is the alternative!

Any help is greatly apprciated.
Thanks in advance.

I'd suggest beginning by turning your "very basic knowledge of
electronics" into a competent level of electronics ability. A good start
would be to pick up a fairly recent electronics book and become very
familiar with transistor circuits (op amp circuits could be helpful as
well). Most electronics texts should have a reasonably lengthy section on
power supplies, so read up on that as well. You should also be fluent in
things like noise, distortion, stability, thermal dynamics, and the physics
of transistor operation.

I highly recommend "The Art of Electronics" by Horowitz and Hill for this
endeavor. There are others out there as well, but I constantly refer back
to this one.

Then you should become accustomed to proper soldering techniques, if
you're not already. If you're going to build from a kit, then this should
be the extent of what's required to be able to build, test, and evaluate
the amplifier. If you want to take a more active role in the design
process, then further hone your transistor circuit analysis skills and
pick up one of the several amplifier books out there. I recommend G.
Randy Slone's book for beginners.


On Sun, 7 Aug 2005 wrote:

I want to build an amplifier for listening music on my computer.
Can anyone suggest where to start? I have very basic knowledge of
electronics but probably need some theory. Any good books?

I searched around on the net and the only thing I can find are complete
schematics and books on how to build tube amplifiers. I'm really not
intersted in tube amps, but since the only information on the net is
about tube amps I dont even know what is the alternative!

Any help is greatly apprciated.
Thanks in advance.

On 7 Aug 2005 00:25:15 -0700, wrote:

I want to build an amplifier for listening music on my computer.

Why do you want to do that? To educate yourself? Not to save money, I
hope. If that is the goal, a used amplifier from the eighties will be
a lot easier and cheaper, most probably.

Can anyone suggest where to start? I have very basic knowledge of
electronics but probably need some theory. Any good books?

I would start by building a readymade kit amplifier and while you do
that read any book on basic electronics. Your local public library
probably has several titles.

I'm really not
intersted in tube amps, but since the only information on the net is
about tube amps I dont even know what is the alternative!

Transistor (also known as solid state) amps.

Per.

On Sun, 07 Aug 2005 13:16:09 +0200, Per Stromgren
wrote:

On 7 Aug 2005 00:25:15 -0700, wrote:

I want to build an amplifier for listening music on my computer.

Why do you want to do that? To educate yourself? Not to save money, I
hope. If that is the goal, a used amplifier from the eighties will be
a lot easier and cheaper, most probably.

Can anyone suggest where to start? I have very basic knowledge of
electronics but probably need some theory. Any good books?

I would start by building a readymade kit amplifier and while you do
that read any book on basic electronics. Your local public library
probably has several titles.

I'm really not
intersted in tube amps, but since the only information on the net is
about tube amps I dont even know what is the alternative!

Transistor (also known as solid state) amps.

It took all of five seconds on Google to find this transistor amp
design site.

http://www.angelfire.com/ab3/mjramp/

And this:

http://www.dself.dsl.pipex.com/ampins/ampins.htm

And check out Hi-Fi World (UK-published) magazine for a good selection
of books on the subject. It ain't hard......................

--

Stewart Pinkerton | Music is Art - Audio is Engineering

wrote in message
oups.com...
I want to build an amplifier for listening music on my computer.
Can anyone suggest where to start? I have very basic knowledge of
electronics but probably need some theory. Any good books?

I searched around on the net and the only thing I can find are complete
schematics and books on how to build tube amplifiers. I'm really not
intersted in tube amps, but since the only information on the net is
about tube amps I dont even know what is the alternative!

Any help is greatly apprciated.
Thanks in advance.

One starting point is building an amplifier based on the TDA2040 IC. It
requires few components and is a bit forgiving (not that I would promote
poor design). It does require a dual power supply with a positive leg and
negative leg. With extra components, it can be made in to a single supply
amp. With a +/- 16 volt supply it will deliver a clean 22 watts into a 4 ohm
load.
It has a wide power supply range from max of +/- 20volts down to 2.5v. I
found it will run down to around +/- 1 volt. Of course, power output is only
a few milliwatts at such low voltages.

I have two of these amps powering a dual voice coil 12" woofer. I used a
speaker design book to build a large ported enclosure for it. It delivers
chest pounding bass.

John

wrote in message
oups.com...
I want to build an amplifier for listening music on my computer.
Can anyone suggest where to start? I have very basic knowledge of
electronics but probably need some theory. Any good books?

The following site lists lots of projects, including some amplifiers.

http://sound.westhost.com/projects.htm

Tim

Is there a reason you want to build one rather than buy one? Used hi-fi
equipment, especially older/simpler stuff, is really cheap and probably
better than anything you're going to build from scratch for a comparable
budget...

The good stuff is rarely really cheap. Plus, there is the educational
value.

Thanks to everybody for replying.

I want to build an amp primarily for several reasons.
1. Get started in electronics.
2. I just like building things. Me and a friend just made a woofer for
his car and it came out so good, I just thought it would be a good time
to start on the amp.
3. I really feel that it is possible to make a better and cheaper
amplifier than most of the *new* stuff on the market (asuming I put
enough effort into it). Or am I wrong? I just dont like the fact that
almost everything nowadays is either a chrome paperweight or made of
plastic in china. So if I dont built a better amp I am sertain I can
built a better quality amp.

Oh and I did google, but try googling asuming that you dont know that
alternative to tube amps are solid state amps ( I heard this before,
just didnt know what it meant). All you'll get are site about tube
amplifiers. Thanks to Per for clarifiying this.

JohnR66 I asume you are talking about the transistor I should use. As
you can see I have no clue what I'm talking about. I better read a book
on electronics first. Once thats done, I'll check it out. Thanks.

"The Art of Electronics" looks like an excellent book. Thanks MZ, I'll
have to get a hold of that one.

I also would be very much interested in an older amplifier that I could
use (or modify a little to use).

Are there any particular ones I should look for?

Thanks.

"pacemkr" wrote in message
ups.com...
Thanks to everybody for replying.

I want to build an amp primarily for several reasons.
1. Get started in electronics.
2. I just like building things. Me and a friend just made a woofer for
his car and it came out so good, I just thought it would be a good time
to start on the amp.
3. I really feel that it is possible to make a better and cheaper
amplifier than most of the *new* stuff on the market (asuming I put
enough effort into it). Or am I wrong? I just dont like the fact that
almost everything nowadays is either a chrome paperweight or made of
plastic in china. So if I dont built a better amp I am sertain I can
built a better quality amp.

Oh and I did google, but try googling asuming that you dont know that
alternative to tube amps are solid state amps ( I heard this before,
just didnt know what it meant). All you'll get are site about tube
amplifiers. Thanks to Per for clarifiying this.

JohnR66 I asume you are talking about the transistor I should use. As
you can see I have no clue what I'm talking about. I better read a book
on electronics first. Once thats done, I'll check it out. Thanks.


The TDA2040 is an integrated circuit chip. ICs are a good start. discreet
component amplifiers require a great depth of understanding, calculation and
even experimentation. Learn about the basic components and ease your way
forward. If your really interested in electronics, you'll keep at it.



"The Art of Electronics" looks like an excellent book. Thanks MZ, I'll
have to get a hold of that one.

Next time I want to build a power amp, this is the one I
will likely select...
http://www.tech-diy.com/lm3875kits.htm

pacemkr wrote:
I also would be very much interested in an older amplifier that I could
use (or modify a little to use).
Are there any particular ones I should look for?

Anything with a line input -- meaning anything that could accept input
from a tape deck or tuner or CD player -- will happily connect to the
line output of your PC's sound hardware. No modification needed, just a
suitable cable easily available from any store that sells stereo components.

Unless there's something you aren't telling us about what you're trying
to do, you're making this _tremendously_ harder than it has to be. Line
out to any decent amp; amp outs to any decent speakers; done.

Yes, but I'd like to preserver the 5.1 capability on my computer. Hence
I need more than one amp?

Also, I have a home theater system that sounds pretty good when playing
from dvd (5.1). The system has a line in (red and white rca plug,
obviously 2 chanel). So I decided to hook up my home theater to the
computer to get some decent sound. So I comfigured the sound card to 2
channel mode. I connected the home theater to the line out. It sounded
like total crap. No lows watsoever, muddy highs... etc, overall
horrible. In other words a line in does not guarantee any quality.

"pacemkr" wrote ...
Yes, but I'd like to preserver the 5.1 capability on my
computer. Hence I need more than one amp?

It would have been extraordinarily helpful to mention
that somewhere before your third posting.

If you want to do 5.1, then yes, you need six amplifiers.


Also, I have a home theater system that sounds pretty good when
playing
from dvd (5.1). The system has a line in (red and white rca plug,
obviously 2 chanel). So I decided to hook up my home theater to the
computer to get some decent sound. So I comfigured the sound card to 2
channel mode. I connected the home theater to the line out. It sounded
like total crap. No lows watsoever, muddy highs... etc, overall
horrible. In other words a line in does not guarantee any quality.

"pacemkr" wrote ...
Yes, but I'd like to preserver the 5.1 capability on my computer.
Hence
I need more than one amp?

Also, I have a home theater system that sounds pretty good when
playing
from dvd (5.1). The system has a line in (red and white rca plug,
obviously 2 chanel). So I decided to hook up my home theater to the
computer to get some decent sound. So I comfigured the sound card to 2
channel mode. I connected the home theater to the line out. It sounded
like total crap. No lows watsoever, muddy highs... etc, overall
horrible.

In other words a line in does not guarantee any quality.

Illogical conclusion. The cause of your problem is NOT
the line-level connection. There are a great many other
things that could be causing the problem.

What kind of a "home theatre system" is this with 5.1
speakers, but no 5.1 input?

On 7 Aug 2005 19:53:20 -0700, "pacemkr" wrote:

Yes, but I'd like to preserver the 5.1 capability on my computer. Hence
I need more than one amp?

Yes, you need three stereo amplifiers, giving six channels total,
the five normal speakers, and a subwoofer for the "point one" channel.

Also, I have a home theater system that sounds pretty good when playing
from dvd (5.1).

Aha, so you already have a box with the six channels.

The system has a line in (red and white rca plug,
obviously 2 chanel). So I decided to hook up my home theater to the
computer to get some decent sound. So I comfigured the sound card to 2
channel mode. I connected the home theater to the line out. It sounded
like total crap. No lows watsoever, muddy highs... etc, overall
horrible. In other words a line in does not guarantee any quality.

There's something wrong somewhere for it to sound as you describe.

-----
http://www.mindspring.com/~benbradley

I'm pretty sure that the problem is the way the reciever of the home
theater system handles the line in signal. All the bass is going to
front channel for no reason at all, while the sub barely works. Its a
really stupid design flaw, since even music CD's that I play on that
thing sound horrible, nothing but treeble...

And I'd rather not use the home theater for this, since it plays dvds
very nice and I dont want to break it.

I dont see how that affects my original question....
I just need more amps as far as I can see. (and you confirmed)

My problem is clearly somewhere inside the home theater reciever.
I am not claming that the actual line in is bad, I'm saying that the
way the reciever handles the line in results in crappy quality. Hence
my original point, the presence of line in does not guarantee any
quality.

Its a Panasonic SC-DT100 if you are really interested.
The 5.1 input can only come from a dvd in this setup.
Its just the way its made.

"pacemkr" wrote in message
ups.com...
I'm pretty sure that the problem is the way the reciever of the home
theater system handles the line in signal. All the bass is going to
front channel for no reason at all, while the sub barely works. Its a
really stupid design flaw, since even music CD's that I play on that
thing sound horrible, nothing but treeble...

And I'd rather not use the home theater for this, since it plays dvds
very nice and I dont want to break it.

That doesn't seem normal to me. I'm going to guess either that the unit is
defective, or it is incorrectly set up.

On 7 Aug 2005 16:37:06 -0700, "pacemkr" wrote:

Thanks to everybody for replying.

I want to build an amp primarily for several reasons.
1. Get started in electronics.
2. I just like building things. Me and a friend just made a woofer for
his car and it came out so good, I just thought it would be a good time
to start on the amp.
3. I really feel that it is possible to make a better and cheaper
amplifier than most of the *new* stuff on the market (asuming I put
enough effort into it). Or am I wrong?

You're wrong.

I just dont like the fact that
almost everything nowadays is either a chrome paperweight or made of
plastic in china.

You might not like the appearance, but that has nothing to do with the
sound quality.

So if I dont built a better amp I am sertain I can
built a better quality amp.

I seriously doubt that.

Oh and I did google, but try googling asuming that you dont know that
alternative to tube amps are solid state amps ( I heard this before,
just didnt know what it meant). All you'll get are site about tube
amplifiers. Thanks to Per for clarifiying this.

I Googled on 'audio amplifier design', and only the 'World Audio
Design' kit site came up on the first two pages as being tube designs.

JohnR66 I asume you are talking about the transistor I should use. As
you can see I have no clue what I'm talking about. I better read a book
on electronics first. Once thats done, I'll check it out. Thanks.

Yet you are 'certain you can build a better quality amp'? Hmmm.

"The Art of Electronics" looks like an excellent book. Thanks MZ, I'll
have to get a hold of that one.

Yes, it is excellent for readers at all levels.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

On 7 Aug 2005 16:50:23 -0700, "pacemkr" wrote:

I also would be very much interested in an older amplifier that I could
use (or modify a little to use).

Are there any particular ones I should look for?

Try the Yamaha AX-570 or its AX5** descendents. Decent power supplies
and good clean sound for very little money.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"pacemkr" wrote in message
ups.com...

And I'd rather not use the home theater for this, since it plays dvds
very nice and I dont want to break it.

OK; do a Google search for "Gainclone". You'll find many successful
amplifiers that have been built by beginners.

Here's one site which looks particularly helpful.

http://myweb.tiscali.co.uk/nuukspot/decdun/

It also has a section specifically aimed at beginners:

http://myweb.tiscali.co.uk/nuukspot/...ncloneFAQ.html

Tim

"pacemkr" wrote ...
I dont see how that affects my original question....
I just need more amps as far as I can see. (and you confirmed)

[Presuming you are responding to your late revelation that
you are looking for a 5.1 solution rather than traditional
stereo. It is helpful to quote what you are responding to
to prevent misunderstanding and confusion.]

So you have already worked out how to do a 5.1 volume
control, and speakers, etc? For better or worse, the usual
expectations of people looking for 5.1 are different than
those looking for traditional 2-channel stereo.

"pacemkr" wrote in message
oups.com

Yes, but I'd like to preserver the 5.1 capability on my
computer. Hence I need more than one amp?

Also, I have a home theater system that sounds pretty
good when playing from dvd (5.1). The system has a line
in (red and white rca plug, obviously 2 chanel). So I
decided to hook up my home theater to the computer to get
some decent sound. So I comfigured the sound card to 2
channel mode. I connected the home theater to the line
out. It sounded like total crap. No lows watsoever, muddy
highs... etc, overall horrible. In other words a line in
does not guarantee any quality.

Let's review the facts:

(1) Receiver driven by DVD player sounds pretty good.
(2) Receiver driven by PC sound card sounds like crap.

The conclusion that was reached - there is something wrong
with the receiver, is totally illogical.

The logical conclusion would be that there is something
wrong with the PC sound card.

Do you have any evidence that contradicts the conclusion
that there is something wrong with the PC sound card?

BTW, do you have any problems with hum when listening to the
PC sound card through the receiver?

"pacemkr" wrote in message
ups.com

I'm pretty sure that the problem is the way the reciever
of the home theater system handles the line in signal.

The receiver should handle a line in signal from the PC
about the same as it handles a stereo CD being played on the
DVD player.

All the bass is going to front channel for no reason at
all, while the sub barely works. Its a really stupid
design flaw, since even music CD's that I play on that
thing sound horrible, nothing but treeble...

When you say "music CDs" where are you playing them, on the
CD drive in the computer or on the DVD player?

And I'd rather not use the home theater for this, since
it plays dvds very nice and I dont want to break it.

There's no way you're going to break something by playing
certain music on it in a reasonable way.

It's beginning to sound like you have problems playing any
stereo source on your HT system. That's usually a matter of
adjustement of the HT system.

"pacemkr" wrote ...
My problem is clearly somewhere inside the home
theater reciever. I am not claming that the actual line
in is bad, I'm saying that the way the reciever handles
the line in results in crappy quality.

Hence my original point, the presence of line in does not
guarantee any quality.

Incorrect conclusion again. When we compare "line-in"
to other methods of interconnection, it IS a higher-quality
option than many others possibly available.

You seem to be confusing general qualities of audio practice
with the particular problems of your (self admitedly broken)
home theatre gadget. Your problem has nothing to do with
line-level technology.

Its a Panasonic SC-DT100 if you are really interested.
The 5.1 input can only come from a dvd in this setup.
Its just the way its made.

"Arny Krueger" wrote in message
...

The logical conclusion would be that there is something
wrong with the PC sound card.

Or maybe the PC setup - eg having an unwanted input enabled But checking
what happens with a different audio source is clearly a good diagnostic
step.

As it happens, I was visiting my son yesterday; he told me that when he
played CDs, only one channel was working. Son, bless him, has no mechanical
sympathy whatsoever.

I said OK; first I listened, and he was right. Checked the balance setting
when listening to CD, that was OK. Checked with another source, and that
was OK - sound from both speakers. So I said yes, there is a problem.
We'll switch the CD input cables to the amplifier, to see if the problem
changes channel. Son said surely all that would happen is the problem would
switch channels; I said it depended on whether problem was with CD player,
or amplifier's CD circuits. Oh yes, said son, that's a good idea.

Swapped the leads over, and - both channels worked fine! I said OK, let's
swap them back - son said why? It's working, why not leave it? I ignored
him - life's too short! - swapped leads back, and ... both channels were
working fine ... :-)

The lead had looked as if it was plugged in, but maybe had not been, or
maybe it was broken, and moving it re-made contacts. Who knows?

Of course, we *could* have solved the problem by buying another amplifier.
When we plugged the CD player in to the new amplifier, it would have worked
fine, thus proving the fault was with the original amplifier ... :-)

Tim

"Tim Martin" wrote in message


As it happens, I was visiting my son yesterday; he told
me that when he played CDs, only one channel was working.
Son, bless him, has no mechanical sympathy whatsoever.

I said OK; first I listened, and he was right. Checked
the balance setting when listening to CD, that was OK.
Checked with another source, and that was OK - sound from
both speakers. So I said yes, there is a problem. We'll
switch the CD input cables to the amplifier, to see if
the problem changes channel. Son said surely all that
would happen is the problem would switch channels; I
said it depended on whether problem was with CD player,
or amplifier's CD circuits. Oh yes, said son, that's a
good idea.

Swapped the leads over, and - both channels worked fine!
I said OK, let's swap them back - son said why? It's
working, why not leave it? I ignored him - life's too
short! - swapped leads back, and ... both channels were
working fine ... :-)

The lead had looked as if it was plugged in, but maybe
had not been, or maybe it was broken, and moving it
re-made contacts. Who knows?

I think this happens to everybody that has more than trivial
amounts of audio experience. I suspect that a ton of the
"mind blowing differences" attributed to audio snake oil
have similar origins.

Of course, we *could* have solved the problem by buying
another amplifier. When we plugged the CD player in to
the new amplifier, it would have worked fine, thus
proving the fault was with the original amplifier ... :-)

Exactly. Or, you could have upgraded your $10,000 amplifier
to a $20,000 amplifier. ;-)

I dont know where you came from Richard, but I was responding to Joe
Kesselmans message about old amps. He suggested I get anything with a
line in, hence I said I want 5.1 in an old amp, hence I said I would
need more than one.

The message had nothing to do with building one it had everything to do
with buying an old amp. I'm a begginer and am not going to jump in and
make studio equipment with surrouns sound in my basement, im not
stupid. I am going to start with a small 2 channel amp. Read message 13
and 14, I think you are confused about what we were talking.

I never said it was broken, I said its the way its made.
Yes I find it stupid that a 5.1 system is made with a 2 channel in
only, but its Panasonic's fault and not mine.

And since one reciever has a problem with line in where is the
guarantee that another I get wont have the same problem?

I am cetrain its set up correctly, and I am fairly sure thats just the
way its made. It may not sound that bad to most people, but I am
critical of sound quality and I tell you its just a half a$$ed job
Panasonic did on this thing. It barely sounds ok as far as I can see.
But yes bass is barely noticeable out of this 500rms (doubt that)
system *when playing from CD's or line in*. DVD's sound pretty good.

Thanks for the links.

Your conclusions seem logical but (2) is a little incorrect.

(2) Reciever driven by line in input or CD (ie any stereo input?)
sounds like crap.

I have dedicated pc speakers (some $50 logitechs) and they sound as
good as they can coming from the sound card.

On FULL volume on both card and pc speakers there is very little
hissing sound.
On normal LOUD listening settings its not noticable.

On the other hand when in Line In mode ( tv (aux) or vcr) on the HT and
NOTHING is connected to the line in (or connected doesnt make a diff)
the sound there is very noticeable hissing sound at LOW volumes. Which
again leads me to believe that the HT is just cheaply built (although
it wasnt cheap).

Also, the hissing on the HT may result from interference of all the
electronic devices that are close. Ill try moving it to see if the
hissing goes away, but that aside, the crappy sound (no bass) remains.

Amusing story. ;-)
I am 100% sure that my sound card is set up correctly though. And I
have tested diff input sources. If I increse the bass in the equalizer
on the computer. The HT plays distorted sound on the front channel. :-(

Thanks to everybody for replying.

I want to build an amp primarily for several reasons.
1. Get started in electronics.
2. I just like building things. Me and a friend just made a woofer for
his car and it came out so good, I just thought it would be a good time
to start on the amp.
3. I really feel that it is possible to make a better and cheaper
amplifier than most of the *new* stuff on the market (asuming I put
enough effort into it). Or am I wrong?

You're wrong.
snip

What is he wrong about? If he's ambitious enough, is willing to put the
time (and money) into it, and is able to learn enough about electronics
beforehand, it's not inconceivable for him to build a high quality amplifier
that in some respects might be as good or better for his application than
what would be available in his price range. Yeah, I know. That's a lot of
ifs. But I certainly wouldn't discourage a relatively harmless endeavor
that could prove to be a greater learning experience in the field of
electronics than he'd likely get doing something else.

On Mon, 8 Aug 2005 13:28:28 -0400, "MZ"
wrote:

Thanks to everybody for replying.

I want to build an amp primarily for several reasons.
1. Get started in electronics.
2. I just like building things. Me and a friend just made a woofer for
his car and it came out so good, I just thought it would be a good time
to start on the amp.
3. I really feel that it is possible to make a better and cheaper
amplifier than most of the *new* stuff on the market (asuming I put
enough effort into it). Or am I wrong?

You're wrong.
snip

What is he wrong about?

That he can make a better and cheaper amplifier than most of the new
stuff on the market.

If he's ambitious enough, is willing to put the
time (and money) into it, and is able to learn enough about electronics
beforehand, it's not inconceivable for him to build a high quality amplifier
that in some respects might be as good or better for his application than
what would be available in his price range.

That would depend on his price range, and if it's more than say $400
it's simply not true. He will also not be able to match a $200
commercial design for $400 parts cost.

Yeah, I know. That's a lot of
ifs. But I certainly wouldn't discourage a relatively harmless endeavor
that could prove to be a greater learning experience in the field of
electronics than he'd likely get doing something else.

Neither would I, but his expectations are totally unrealistic.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

That would depend on his price range, and if it's more than say $400
it's simply not true. He will also not be able to match a $200
commercial design for $400 parts cost.

I'm not so sure I agree with that. Beyond a transformer, heatsinks, and a
suitable case - all items that aren't terribly difficult to find in online
surplus, the parts shouldn't exceed very much at all.

Then again, I haven't priced home audio equipment in nearly 10 years, so
admittedly I have no idea what's available these days for $200.


Yeah, I know. That's a lot of
ifs. But I certainly wouldn't discourage a relatively harmless endeavor
that could prove to be a greater learning experience in the field of
electronics than he'd likely get doing something else.

Neither would I, but his expectations are totally unrealistic.

I don't see how. It's unrealistic to build an amplifier? I think he's
mischaracterized the quality of products made in China, but he did state
that one of his goals was to learn. It's a worthwhile endeavor, and perhaps
a superior option for him than to just go out and buy an old amp (or three,
as we've come to find out - or probably actually four, if he decides he
wants more power going to his sub).