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Audio amlifier.

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August 7, 2005 4:25:15 AM

Archived from groups: rec.audio.tech (More info?)

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.

More about : audio amlifier

Anonymous
August 7, 2005 11:54:25 AM

Archived from groups: rec.audio.tech (More info?)

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 pacemkr@gmail.com 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.
>
>
Anonymous
August 7, 2005 5:16:09 PM

Archived from groups: rec.audio.tech (More info?)

On 7 Aug 2005 00:25:15 -0700, pacemkr@gmail.com 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.
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Anonymous
August 7, 2005 5:16:10 PM

Archived from groups: rec.audio.tech (More info?)

On Sun, 07 Aug 2005 13:16:09 +0200, Per Stromgren
<per.stromgren@telia.com> wrote:

>On 7 Aug 2005 00:25:15 -0700, pacemkr@gmail.com 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
Anonymous
August 7, 2005 5:22:33 PM

Archived from groups: rec.audio.tech (More info?)

<pacemkr@gmail.com> wrote in message
news:1123399515.821904.300230@f14g2000cwb.googlegroups.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
Anonymous
August 7, 2005 8:12:12 PM

Archived from groups: rec.audio.tech (More info?)

The good stuff is rarely really cheap. Plus, there is the educational
value.
August 7, 2005 8:37:06 PM

Archived from groups: rec.audio.tech (More info?)

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.
August 7, 2005 8:50:23 PM

Archived from groups: rec.audio.tech (More info?)

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.
Anonymous
August 7, 2005 10:34:16 PM

Archived from groups: rec.audio.tech (More info?)

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...
Anonymous
August 8, 2005 1:52:19 AM

Archived from groups: rec.audio.tech (More info?)

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.
Anonymous
August 8, 2005 2:14:24 AM

Archived from groups: rec.audio.tech (More info?)

<pacemkr@gmail.com> wrote in message
news:1123399515.821904.300230@f14g2000cwb.googlegroups.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
August 8, 2005 2:22:14 AM

Archived from groups: rec.audio.tech (More info?)

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.
August 8, 2005 2:26:01 AM

Archived from groups: rec.audio.tech (More info?)

I dont see how that affects my original question....
I just need more amps as far as I can see. (and you confirmed)
Anonymous
August 8, 2005 3:53:29 AM

Archived from groups: rec.audio.tech (More info?)

"pacemkr" <pacemkr@gmail.com> wrote in message
news:1123457826.233666.38440@z14g2000cwz.googlegroups.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.
>
Anonymous
August 8, 2005 7:08:49 AM

Archived from groups: rec.audio.tech (More info?)

"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.
Anonymous
August 8, 2005 9:41:50 AM

Archived from groups: rec.audio.tech (More info?)

"pacemkr" <pacemkr@gmail.com> wrote in message
news:1123478533.999452.80870@o13g2000cwo.googlegroups.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.
Anonymous
August 8, 2005 9:55:47 AM

Archived from groups: rec.audio.tech (More info?)

On 7 Aug 2005 16:37:06 -0700, "pacemkr" <pacemkr@gmail.com> 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
Anonymous
August 8, 2005 9:57:09 AM

Archived from groups: rec.audio.tech (More info?)

On 7 Aug 2005 16:50:23 -0700, "pacemkr" <pacemkr@gmail.com> 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
Anonymous
August 8, 2005 10:17:24 AM

Archived from groups: rec.audio.tech (More info?)

"pacemkr" <pacemkr@gmail.com> wrote in message
news:1123478533.999452.80870@o13g2000cwo.googlegroups.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.
August 8, 2005 1:12:50 PM

Archived from groups: rec.audio.tech (More info?)

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.
August 8, 2005 1:16:49 PM

Archived from groups: rec.audio.tech (More info?)

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?
August 8, 2005 1:20:36 PM

Archived from groups: rec.audio.tech (More info?)

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.
August 8, 2005 1:21:08 PM

Archived from groups: rec.audio.tech (More info?)

Thanks for the links.
August 8, 2005 1:38:22 PM

Archived from groups: rec.audio.tech (More info?)

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. :-(
Anonymous
August 8, 2005 2:04:35 PM

Archived from groups: rec.audio.tech (More info?)

"pacemkr" <pacemkr@gmail.com> wrote in message
news:1123478533.999452.80870@o13g2000cwo.googlegroups.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/decdun/gaincloneFAQ...

Tim
Anonymous
August 8, 2005 3:28:29 PM

Archived from groups: rec.audio.tech (More info?)

"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:nMGdnb9_YozXrWrfRVn-iQ@comcast.com...

> 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
Anonymous
August 8, 2005 3:28:30 PM

Archived from groups: rec.audio.tech (More info?)

"Tim Martin" <tim2718281@ntlworld.com> wrote in message
news:xlHJe.24407$bT4.17285@newsfe1-gui.ntli.net

> 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. ;-)
Anonymous
August 8, 2005 5:28:28 PM

Archived from groups: rec.audio.tech (More info?)

> >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.
Anonymous
August 8, 2005 8:58:18 PM

Archived from groups: rec.audio.tech (More info?)

"pacemkr" wrote...
> I dont know where you came from Richard, ...

And likewise, I have no idea what you are refering to as you did
not quote the text you are talking about.

Hint: This may be the only conversation that YOU are participating
in at the moment, but you can safely assume that the rest of us are
reading/replying to 20~200 other message threads, likely in several
other newsgroups besides this one. We can't memorize what you
said or guess what you are replying to.

> The message had nothing to do with building one it had everything
> to do with buying an old amp. I'm a begginer....

You have some pretty strong misconceptions to overcome as
a beginner.

> Read message 13 and 14, I think you are confused about what
> we were talking.

You are the only one who knows what "message 13 and 14" mean.
The rest of us have no idea what you are talking about unless you
quote the *actual text* you are responding to. That is how Usenet
works. Like it or not.
Anonymous
August 8, 2005 9:32:52 PM

Archived from groups: rec.audio.tech (More info?)

On Mon, 8 Aug 2005 13:28:28 -0400, "MZ"
<myfirstname@mdz.junk.no-ip.junk.org> 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
Anonymous
August 8, 2005 9:32:53 PM

Archived from groups: rec.audio.tech (More info?)

> 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).
Anonymous
August 9, 2005 1:31:03 AM

Archived from groups: rec.audio.tech (More info?)

On Mon, 08 Aug 2005 10:04:35 GMT, "Tim Martin"
<tim2718281@ntlworld.com> wrote:

>
>"pacemkr" <pacemkr@gmail.com> wrote in message
>news:1123478533.999452.80870@o13g2000cwo.googlegroups.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.

Hmmmm. The gainclone is an IC amplifier - definitely *not* 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/decdun/gaincloneFAQ...
>
>Tim
>
>

--

Stewart Pinkerton | Music is Art - Audio is Engineering
Anonymous
August 9, 2005 1:54:09 AM

Archived from groups: rec.audio.tech (More info?)

"MZ" <myfirstname@mdz.junk.no-ip.junk.org> wrote in message
news:D 7Kdna9jte26BGrfRVn-hA@giganews.com...
> > 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.

I recently costed a power amplifier project from Rod Elliott's site (Project
3A)

The context was the economics of bi-amping; and according to my estimate,
the guide cost, using all new parts, was the cost of a transformer (about
$50, more for more channels), cost of a case, plus $50 per channel. Of that
$50 per channel, about $15 was for the PCB, $15 was for the heatsink, and
$10 was for the power supply components (bridge rectifier plus capacitors.)

If you start with an old power amplifier, and are able to use the case,
transformer, and heatsink, the cost might come down to just $35 per channel.

Tim
Anonymous
August 9, 2005 1:54:10 AM

Archived from groups: rec.audio.tech (More info?)

> I recently costed a power amplifier project from Rod Elliott's site
(Project
> 3A)
>
> The context was the economics of bi-amping; and according to my estimate,
> the guide cost, using all new parts, was the cost of a transformer (about
> $50, more for more channels), cost of a case, plus $50 per channel. Of
that
> $50 per channel, about $15 was for the PCB, $15 was for the heatsink, and
> $10 was for the power supply components (bridge rectifier plus
capacitors.)
>
> If you start with an old power amplifier, and are able to use the case,
> transformer, and heatsink, the cost might come down to just $35 per
channel.

I've encountered very few people who use all new parts though. Heatsinks
can be tough to get a hold of if you're after a particular arrangement, but
there are a ton of them (quite literally, I'm sure) on ebay for short money.
The real problem is the transformer and the output transistors. The former
can be scavenged if you're crafty, and the latter you just have to pony up.
Your PS and PCB numbers seem reasonable, but $50 seems a bit on the high
side per channel. The relation between $$ and parts is probably not linear
if you're putting together 6 channels of amplification, especially when it
comes to resistors and small-signal BJTs. A good inductor for the outputs
can be a little pricey as well, but probably not essential (depending on who
you ask) and, again, are not terribly hard to find used/surplus.

Also, it wouldn't be terribly costly to improve upon the ESP design if you
want to improve the specs, though I personally see very little reason to do
so. But occasionally, smaller parallel OPS transistors or MOSFETs will do
the trick just as well and can save you a few bucks too. Really, surplus is
the key for a hobbyist on a budget. The original poster didn't really
mention a budget, so I don't know what his goal is in that respect. It
seemed he was interested in "better quality", but there's some debate about
exactly what that means.

Frankly, the only part that I see as cost prohibitive is the test equipment
that he may need to buy if he doesn't have it already. But I'm sure if he's
serious about getting into electronics, he'd be buying this stuff anyway.
Basically, it just comes down to how serious he is and whether the learning
process or the price (relative to used equipment, as some have suggested) is
more important to him.
Anonymous
August 9, 2005 1:54:31 AM

Archived from groups: rec.audio.tech (More info?)

On Mon, 8 Aug 2005 13:42:00 -0400, "MZ"
<myfirstname@mdz.junk.no-ip.junk.org> wrote:

>> 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.

More to the point, you have no idea how to *optimise* $400 of parts
purchased at one-off prices. You'll find that this is about $100 (or
less) at 10,000 off prices, making for about a $400 retail device from
a large manufacturer. Why do you think all the new budget stuff is
made in China?

>> > 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?

Don't be disingenuous - it's unrealistic to expect to improve on
currently available cheap amps, the big two-channel Yamahas being
particularly fine ecxamples.

> 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).

Indeed, but it depends on his goal. Is it to learn, or to get best
value for money from the electronics in his system?
--

Stewart Pinkerton | Music is Art - Audio is Engineering
Anonymous
August 9, 2005 1:54:32 AM

Archived from groups: rec.audio.tech (More info?)

> >> 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.
>
> More to the point, you have no idea how to *optimise* $400 of parts
> purchased at one-off prices. You'll find that this is about $100 (or
> less) at 10,000 off prices, making for about a $400 retail device from
> a large manufacturer.

Then you're shopping at the wrong places. Although I haven't priced home
audio amplifiers lately, I've built one recently and am currently in the
process of putting together another. Neither are component-sparse. The
most expensive part is the case, but I wanted a rack-mount chassis so
naturally it would be a little more costly.

> Why do you think all the new budget stuff is
> made in China?

To maximize profit margin. Duh. Cheap labor, cheaper parts.


> >I don't see how. It's unrealistic to build an amplifier?
>
> Don't be disingenuous - it's unrealistic to expect to improve on
> currently available cheap amps, the big two-channel Yamahas being
> particularly fine ecxamples.
>
> > 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).
>
> Indeed, but it depends on his goal. Is it to learn, or to get best
> value for money from the electronics in his system?

I think he wants the best of both worlds. But it's worth noting that the
first two of his three reasons had to do with simply wanting to construct
it. You're spending so much time trying to dissuade him that it's hard to
identify exactly what your motivation is.
Anonymous
August 9, 2005 2:37:37 AM

Archived from groups: rec.audio.tech (More info?)

On 8 Aug 2005 09:12:50 -0700, "pacemkr" <pacemkr@gmail.com> wrote:

>I dont know where you came from Richard, but I was responding to Joe
>Kesselmans message about old amps.

Pacemkr, you must include the post you answer in order for us to see
whom you are talking to, exactly as I does with your message now. If
you are new to Usenet, and does not know how it works, I recommend
reading any of the many texts on the topic.

>Read message 13
>and 14, I think you are confused about what we were talking.

This is *not* the way to do it, include the text!

If you need help with configuring your news reader, we can probably
help you out.

Per.
August 9, 2005 2:50:50 AM

Archived from groups: rec.audio.tech (More info?)

MZ wrote:
> I've encountered very few people who use all new parts though. Heatsinks
> can be tough to get a hold of if you're after a particular arrangement, but
> there are a ton of them (quite literally, I'm sure) on ebay for short money.
> The real problem is the transformer and the output transistors. The former
> can be scavenged if you're crafty, and the latter you just have to pony up.
> Your PS and PCB numbers seem reasonable, but $50 seems a bit on the high
> side per channel. The relation between $$ and parts is probably not linear
> if you're putting together 6 channels of amplification, especially when it
> comes to resistors and small-signal BJTs. A good inductor for the outputs
> can be a little pricey as well, but probably not essential (depending on who
> you ask) and, again, are not terribly hard to find used/surplus.
>
> Also, it wouldn't be terribly costly to improve upon the ESP design if you
> want to improve the specs, though I personally see very little reason to do
> so. But occasionally, smaller parallel OPS transistors or MOSFETs will do
> the trick just as well and can save you a few bucks too. Really, surplus is
> the key for a hobbyist on a budget. The original poster didn't really
> mention a budget, so I don't know what his goal is in that respect. It
> seemed he was interested in "better quality", but there's some debate about
> exactly what that means.

My budget is floating $250 for the amp. That would be for a 6 channel amp, which I would probably not start building right away,
unless I am very confident once I educate myself enough. I will probably start with a 2 channel amp I'm asuming I can do that for
about $100?

> Frankly, the only part that I see as cost prohibitive is the test equipment
> that he may need to buy if he doesn't have it already. But I'm sure if he's
> serious about getting into electronics, he'd be buying this stuff anyway.
> Basically, it just comes down to how serious he is and whether the learning
> process or the price (relative to used equipment, as some have suggested) is
> more important to him.

I can asure you I am VERY serious about getting into electronics. There is absolutely no doubt in my mind that thats what I really
want to do. I am currently a sophmore with a CompE major. I feel that I am very competent when it comes to programming.
Electronics being the second part of my major I am very much interested and always have been. That said I have absolutely no
problem investing into test equipment and the like. I'm not saying I'm loaded, far from that, I just feel this is something worth
investing in.
Anonymous
August 9, 2005 3:00:35 AM

Archived from groups: rec.audio.tech (More info?)

"MZ" <myfirstname@mdz.junk.no-ip.junk.org> wrote in message
news:H5CdnWnf3a9ZR2rfRVn-vQ@giganews.com...

> The original poster didn't really
mention a budget, so I don't know what his goal is in that respect.

> Your PS and PCB numbers seem reasonable, but $50 seems a bit on the high
> side per channel.

Just to be clear, that $50 per channel was made up of

$15 for PCB
$15 for heat sink
$10 for power supply components (bridge rectifier and capacitors)
$10 for amplifier electronics components (transistors, resistors,
capacitors, LED, fuses, and preset resistor)

I agree you could save money on the heat sink, and probably on the amplifier
electronics.

Tim
Anonymous
August 9, 2005 3:00:36 AM

Archived from groups: rec.audio.tech (More info?)

> > Your PS and PCB numbers seem reasonable, but $50 seems a bit on the high
> > side per channel.
>
> Just to be clear, that $50 per channel was made up of
>
> $15 for PCB
> $15 for heat sink
> $10 for power supply components (bridge rectifier and capacitors)
> $10 for amplifier electronics components (transistors, resistors,
> capacitors, LED, fuses, and preset resistor)
>
> I agree you could save money on the heat sink, and probably on the
amplifier
> electronics.


Ah, I see now. Well, you'd save money by putting more than one channel on a
single PCB, using a single heat sink for multiple output stages, and of
course using a single power supply to run the channels. Yeah, with 6
channels you'll need a beefier rectifier and bigger capacitors.
August 9, 2005 3:14:25 AM

Archived from groups: rec.audio.tech (More info?)

Per Stromgren wrote:
> This is *not* the way to do it, include the text!
>
> If you need help with configuring your news reader, we can probably
> help you out.
>
> Per.

I was using google groups to post replies, and it just doesnt include the text by default, sorry about that. I had a newsgroup
reader setup on my other computer, so I'm using that to post now.
Anonymous
August 9, 2005 8:55:25 AM

Archived from groups: rec.audio.tech (More info?)

pacemkr <pacemkr@gmail.com> wrote:
> MZ wrote:
> > I've encountered very few people who use all new parts though. Heatsinks
>> can be tough to get a hold of if you're after a particular arrangement, but
>> there are a ton of them (quite literally, I'm sure) on ebay for short money.
>> The real problem is the transformer and the output transistors. The former
>> can be scavenged if you're crafty, and the latter you just have to pony up.
>> Your PS and PCB numbers seem reasonable, but $50 seems a bit on the high
>> side per channel. The relation between $$ and parts is probably not linear
>> if you're putting together 6 channels of amplification, especially when it
>> comes to resistors and small-signal BJTs. A good inductor for the outputs
>> can be a little pricey as well, but probably not essential (depending on who
>> you ask) and, again, are not terribly hard to find used/surplus.
>>
>> Also, it wouldn't be terribly costly to improve upon the ESP design if you
>> want to improve the specs, though I personally see very little reason to do
>> so. But occasionally, smaller parallel OPS transistors or MOSFETs will do
>> the trick just as well and can save you a few bucks too. Really, surplus is
>> the key for a hobbyist on a budget. The original poster didn't really
>> mention a budget, so I don't know what his goal is in that respect. It
>> seemed he was interested in "better quality", but there's some debate about
>> exactly what that means.
>
> My budget is floating $250 for the amp. That would be for a 6 channel amp, which I would probably not start building right away,
> unless I am very confident once I educate myself enough. I will probably start with a 2 channel amp I'm asuming I can do that for
> about $100?

Off the top of my head, I'd guess $500 to build a decent 2-channel amp, where
"decent" means "as good as anything you could buy with your eyes closed."
Others can expand on this guess, but that's what I'd start with. A hundred
bucks might be a fascinating and educational project, but it's not going to
get you much of an amp from scratch.

> I can asure you I am VERY serious about getting into electronics. There is absolutely no doubt in my mind that thats what I really
> want to do. I am currently a sophmore with a CompE major. I feel that I am very competent when it comes to programming.
> Electronics being the second part of my major I am very much interested and always have been. That said I have absolutely no
> problem investing into test equipment and the like. I'm not saying I'm loaded, far from that, I just feel this is something worth
> investing in.

Then by all means, get the parts, design and build an amp, learn from your
mistakes, and then do it all over again! But you might want to shell out
the money for a two or six channel amp to use in the three intervening years.
:-)

Colin
Anonymous
August 9, 2005 9:04:33 AM

Archived from groups: rec.audio.tech (More info?)

> > My budget is floating $250 for the amp. That would be for a 6 channel amp, which I would probably not start building right away,
> > unless I am very confident once I educate myself enough. I will probably start with a 2 channel amp I'm asuming I can do that for
> > about $100?
>
> Off the top of my head, I'd guess $500 to build a decent 2-channel amp, where
> "decent" means "as good as anything you could buy with your eyes closed."
> Others can expand on this guess, but that's what I'd start with. A hundred
> bucks might be a fascinating and educational project, but it's not going to
> get you much of an amp from scratch.

$100 might be a lofty goal, yeah, but $500 is a little over the top unless
you're spending the bulk of that money on the case, fancy connectors, or
"designer" components. An *excellent* audio amplifier will incorporate
more small signal components than what showed up, for example, in that ESP
schematic that someone posted the link to. It'll incorporate maybe an
added pair of output transistors (so you're not living on the edge), a
good transformer (probably the most expensive part of the amp), and
probably relatively large air core inductors at each output. Even so, it
shouldn't cost up to $500 as far as components go.
Anonymous
August 9, 2005 9:04:34 AM

Archived from groups: rec.audio.tech (More info?)

MZ wrote:

>>>My budget is floating $250 for the amp. That would be for a 6 channel amp, which I would probably not start building right away,
>>>unless I am very confident once I educate myself enough. I will probably start with a 2 channel amp I'm asuming I can do that for
>>>about $100?
>>
>>Off the top of my head, I'd guess $500 to build a decent 2-channel amp, where
>>"decent" means "as good as anything you could buy with your eyes closed."
>>Others can expand on this guess, but that's what I'd start with. A hundred
>>bucks might be a fascinating and educational project, but it's not going to
>>get you much of an amp from scratch.
>
>
> $100 might be a lofty goal, yeah, but $500 is a little over the top unless
> you're spending the bulk of that money on the case, fancy connectors, or
> "designer" components. An *excellent* audio amplifier will incorporate
> more small signal components than what showed up, for example, in that ESP
> schematic that someone posted the link to. It'll incorporate maybe an
> added pair of output transistors (so you're not living on the edge), a
> good transformer (probably the most expensive part of the amp), and
> probably relatively large air core inductors at each output. Even so, it
> shouldn't cost up to $500 as far as components go.
>
>

I guess I'll just have to build one and see. Thanks for all the help.
Anonymous
August 9, 2005 2:04:13 PM

Archived from groups: rec.audio.tech (More info?)

"pacemkr" <pacemkr@gmail.com> wrote in message
news:8SUJe.23922$sf6.15024@fe08.lga...

> Electronics being the second part of my major I am very much interested
and always have been. That said I have absolutely no
> problem investing into test equipment and the like. I'm not saying I'm
loaded, far from that, I just feel this is something worth
> investing in.

Go for it. I picked out two sites (Rod Elliott's ESP site and the Decibel
Dungeon site) which have construction guidelines aimed at those unfamiliar
with amplifier construction.. I think those guidelines are helpful, even if
you're building different designs. And of course if you're doing an
electronics course, you'll have lots of assistance and test equipment on
hand.

The chip-amp designs are reported to be very high quality if working within
their specs; they need little test equipment, and the low component count
means they can be built without PCBs.

Why not take the chip-amp designs from Decibel Dungeon and the ESP projects
pages and cost them yourself?

Tim
Anonymous
August 9, 2005 9:25:54 PM

Archived from groups: rec.audio.tech (More info?)

On Mon, 8 Aug 2005 18:05:55 -0400, "MZ"
<myfirstname@mdz.junk.no-ip.junk.org> wrote:

>> >> 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.
>>
>> More to the point, you have no idea how to *optimise* $400 of parts
>> purchased at one-off prices. You'll find that this is about $100 (or
>> less) at 10,000 off prices, making for about a $400 retail device from
>> a large manufacturer.
>
>Then you're shopping at the wrong places.

No, I'm designing a nominally-rated 100 watt/channel amp which will
put 200 watts *continuous* into a 4-ohm load with a 60 degree phase
angle. IOW, a half-decent hi-fi amp. Nothing special, a 500 series
Yamaha amp will equal that performance.

> Although I haven't priced home
>audio amplifiers lately, I've built one recently and am currently in the
>process of putting together another. Neither are component-sparse. The
>most expensive part is the case, but I wanted a rack-mount chassis so
>naturally it would be a little more costly.

The most expensive part *should* be the power supply.

>> Why do you think all the new budget stuff is
>> made in China?
>
>To maximize profit margin. Duh. Cheap labor, cheaper parts.

And cheap retail price (the Mark Levinson Red Rose ripoff excepted!)

>> >I don't see how. It's unrealistic to build an amplifier?
>>
>> Don't be disingenuous - it's unrealistic to expect to improve on
>> currently available cheap amps, the big two-channel Yamahas being
>> particularly fine ecxamples.
>>
>> > 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).
>>
>> Indeed, but it depends on his goal. Is it to learn, or to get best
>> value for money from the electronics in his system?
>
>I think he wants the best of both worlds. But it's worth noting that the
>first two of his three reasons had to do with simply wanting to construct
>it. You're spending so much time trying to dissuade him that it's hard to
>identify exactly what your motivation is.

I'm not trying to dissuade him, I'm simply trying to manage his
expectations.
--

Stewart Pinkerton | Music is Art - Audio is Engineering
Anonymous
August 9, 2005 9:29:49 PM

Archived from groups: rec.audio.tech (More info?)

On Tue, 09 Aug 2005 05:04:33 GMT, MZ <mark@mdz.no-ip.org> wrote:

>> > My budget is floating $250 for the amp. That would be for a 6 channel amp, which I would probably not start building right away,
>> > unless I am very confident once I educate myself enough. I will probably start with a 2 channel amp I'm asuming I can do that for
>> > about $100?
>>
>> Off the top of my head, I'd guess $500 to build a decent 2-channel amp, where
>> "decent" means "as good as anything you could buy with your eyes closed."
>> Others can expand on this guess, but that's what I'd start with. A hundred
>> bucks might be a fascinating and educational project, but it's not going to
>> get you much of an amp from scratch.
>
>$100 might be a lofty goal, yeah, but $500 is a little over the top unless
>you're spending the bulk of that money on the case, fancy connectors, or
>"designer" components. An *excellent* audio amplifier will incorporate
>more small signal components than what showed up, for example, in that ESP
>schematic that someone posted the link to. It'll incorporate maybe an
>added pair of output transistors (so you're not living on the edge), a
>good transformer (probably the most expensive part of the amp), and
>probably relatively large air core inductors at each output. Even so, it
>shouldn't cost up to $500 as far as components go.

Why on earth would you put large inductors at the output? And yes, a
decent '100 watt' 2-channel amp will cost $500 in parts, and that's
without a particularly fancy case. Remember, to do it right will
require a *minimum* 600 VA power transformer, and everything else that
entails.
--

Stewart Pinkerton | Music is Art - Audio is Engineering
Anonymous
August 10, 2005 5:59:28 AM

Archived from groups: rec.audio.tech (More info?)

On Mon, 08 Aug 2005 23:20:47 -0400, pacemkr <pacemkr@gmail.com> wrote:

>Richard Crowley wrote:
>
>> "pacemkr" wrote ...

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

There is no guarantee, it might be a design problem with that model
receiver.

>> If you find another one with that problem, take it back the
>> next day and get one that isn't broken. Your assumption
>> that all amplifiers with line inputs will behave like your broken
>> equipment is just silly.
>>
>
>Stop putting words in my mouth. I said that if there exists one
>amp that cant use its own line in properly, then there may exist
>more.

There indeed may exist more, but not that many of us have seen.
"Line in" on consumer equipment has been standardized for decades,
more like half a century (even though I recall CD players having
slightly more output than the "standard", it's not enough to worry
about, any "line in" can handle it), and I and millions of others have
been able to connect "line out" of phono preamps, stereo tuners, tape
decks, CD's and computer soundcards into "line in" of tape decks, CD
recorders, computer soundcards, aux and tape inputs of stereo
receivers for all these decades, and they WORK, it's a no-brainer.
Some situations where this "did not work" (which might have
involved personal experience, but I'd rather not admit it) involve
such things as connecting line in to line in, or line out to line out,
or having a few extra RCA-terminated cables laying around and plugging
an otherwise-unused one to a line in, and another otherwise-unused one
to a line out.
You have a (rare) situation where it does NOT work, hence the
conclusion that there's something wrong with your equipment, whether
it's the design, the configuration, or who knows what.
Please recheck your connections. If there's something with a
microcontroller inside (more and more stuff does thesedays), turn it
off and unplug from the power socket for at least ten seconds, then
plug it in and turn it back on. Say a prayer to the deity of your
choice. Pay your power bill. Many of us have found that doing all of
this and more has sometimes been necessary to make an audio system
work.

>Hence I come back to my original point the presence of a line in
>*does not* guarantee quality from that line in. In fact I
>cant find anything usefull out of everything you said in your post,
>you just keep criticising me for reasons unknown...

-----
http://www.mindspring.com/~benbradley
Anonymous
August 13, 2005 1:58:58 PM

Archived from groups: rec.audio.tech (More info?)

> >$100 might be a lofty goal, yeah, but $500 is a little over the top unless
> >you're spending the bulk of that money on the case, fancy connectors, or
> >"designer" components. An *excellent* audio amplifier will incorporate
> >more small signal components than what showed up, for example, in that ESP
> >schematic that someone posted the link to. It'll incorporate maybe an
> >added pair of output transistors (so you're not living on the edge), a
> >good transformer (probably the most expensive part of the amp), and
> >probably relatively large air core inductors at each output. Even so, it
> >shouldn't cost up to $500 as far as components go.
>
> Why on earth would you put large inductors at the output?

OPS/global NFB stability. As I said, it's not essential but some people
do it. Really, the only time I'd do it is when the amplifier will be
operating up to 20kHz (eg. not a dedicated sub or midbass amp) and if I
wasn't using a typical EF OPS design. I used some in my last amp mostly
because I had a bunch of large inductors kicking around in my closet that
I had purchased a couple years ago for a passive xover I didn't end up
building.


> And yes, a
> decent '100 watt' 2-channel amp will cost $500 in parts, and that's
> without a particularly fancy case. Remember, to do it right will
> require a *minimum* 600 VA power transformer, and everything else that
> entails.

I guess we'll just have to agree to disagree on cost. If you know how to
shop, then you won't be spending $500 on a transformer, rectifier,
capacitors, and output transistors. Not for a 100 watt amp. Everything
else is relatively cheap if you shop wisely.
!