class A amplifier

[Eeyore]

Olivier Scalbert wrote:

Eeyore wrote:
Olivier Scalbert wrote:
john jardine wrote:
For a starter, increase C1 to 1000uF. 'T'll get the response down to about
20Hz.

Thanks !
Done.
I will try to find high quality capacitors later ...

The 'quality' of capaciors is an entire irrelevance with something so primitive.
In fact it's almost a complete irrelevance completely unless you buy Asian junk.

I take it you've been 'Audiophooled' by reading magazines written by wholesale
fraudsters. Audiophile was it ?

Graham (pro-audio designer since 1971)

Graham, why are you so aggressive with me ?
What is your problem ?

I am not being aggresive. I'm teaching you some valuable facts.

I have read it in Farnell catalog.

That's called marketing. Nor is the Farnell catalgue a textbook, despite its other
excellent uses. Do you think the CDs or whatever you listen to were produced on
equipment using these stupid caps ? I can tell you for a fact because I design such
equipment that there's not a hope in hell real designers take these audiophool pieces
of junk seriously.

Graham

 

[Eeyore]

John Fields wrote:

Eeyore wrote:
Olivier Scalbert wrote:
john jardine wrote:
For a starter, increase C1 to 1000uF. 'T'll get the response down to about
20Hz.

Thanks !
Done.
I will try to find high quality capacitors later ...

The 'quality' of capaciors is an entire irrelevance with something so primitive.
In fact it's almost a complete irrelevance completely unless you buy Asian junk.

---
Since John Jardine suggested that he increase the _capacitance_ of C1 to
1000ľF, I'm sure Olivier took that to mean the capacitor would be higher
quality since it would extend the audio response of the amp down to
about 20Hz.

No, I'll bet he's referring I expect to audiophool parts, and you of ALL people
should berate him for that.

OTOH if the guy can't distinguish *capacitance value* from *quality* he shouldn't
even have started.

You see, you don't understand this field. The audiophools promote crap circuits built
with absurdly expensive components because they think the cost of the parts is what
determines the result.

This is the kind of thinking that drives the pro-audio guys mad !

Graham

 

[Eeyore]

John Fields wrote:

Olivier Scalbert wrote:
John Fields wrote:

And as I have no good electronic shop near my home, I generally buy my
components at Farnell.
By looking inside the 2006 edition, I have discovered page 936 the ECA
audio caps from Panasonic.
"High fidelity, low distorsion, High resolution, ...."

That is why I will buy these ones !

---
In this case, then, I'm afraid that Graham is right since the audible
output of your circuit will hardly be improved by the use of "High
fidelity, low distorsion, High resolution, ...." capacitors.

Apology please ?

I could smell it 100 miles off.

Graham

 

[Eeyore]

mrdarrett@gmail.com wrote:

Just as long as they're large enough, and don't suffer from Capacitor
Plague...

That's why I mentioned the 'crap' Asian caps.

Plain ordinary Panasonic electrolytics are just fine. Indeed they're one of my faves
since they're moderately priced and have good general specs.

Graham

 

[Eeyore]

mrdarrett@gmail.com wrote:

He does know his audio stuff though.

Which is why all my posts in this thread are correct.

Graham

 

[Eeyore]

John Fields wrote:

Graham, why are you so aggressive with me ?
What is your problem ?

---
I believe both of his parents died when he was very young

Fairly young and was that simply a guess ? But it never made me aggressive.

and he's been angry and taking it out on the whole world ever since.

No, I just hate audiophools. They are trying to destroy a once proud and technically
highly competent industry with their claims of 'magic parts' and other pixie dust
garbage.

Graham

 

[Eeyore]

mrdarrett@gmail.com wrote:

Say... what *is* your ultimate objective, by the way? If you want a
good (reasonably efficient, relatively cheap, good sound quality,
medium power) solution quickly, you may be happy with the LM3886.
http://www.national.com/mpf/LM/LM3886.html

Guess what's used in the 'gainclone' I recommended he google ?

Graham

 

[John Fields]

On Tue, 14 Oct 2008 23:13:03 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

John Fields wrote:

Eeyore wrote:
John Fields wrote:

Just simple facts John.

Graham

---
You're a goddam liar.

You know very well that this is seb and that instead of just putting the
guy down by puffing yourself up as an "expert" (implying that he's a
virtual nonentity) you should be helping him understand where his
deficiencies lie, like Larkin did.

But no, you always have to try to make yourself feel important by trying
to make it seem like everyone is less important.

JF

I have given him a link to a far far better site.
http://www.dself.dsl.pipex.com/ampins/ampins.htm

---
After the fact.

But anyway, "Onward through the fog"...

JF

 

[John Larkin]

On Tue, 14 Oct 2008 23:20:47 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

John Larkin wrote:

Olivier Scalbertwrote:
Eeyore wrote:

Stop mucking about with stuff you don't understand and simply buy a modern
hi-fi amp. Power amps are a real speciality (especially if you want them
to be stable). It's no place for a beginner.

Do you understand stabilty criteria for example. What's a Bode plot ? etc

Graham (designer of stable pro-audio power amps since 1980)

I have studied Bode, Nyquist, Smith diagrams, Z, Laplace, Fourier
transformations and their digital implementations, ...

So I think I can read technical answers to my "beginners" questions.

Oh, by the way, I must admit that I have miss the training "how to
become arrogant".

Hey, this is usenet. It selectively attracts the willfully ignorant,
the arrogant, and the pain sluts who crave public humiliation.

Why not drive the base of your darlington with an opamp?

The BC546 is far too tiny to drive a 2N3055 intelligently. It's TO-92 FFS but you
Americans aren't so familiar with our European (Pro-Electron) devices are you ?

Of course we aren't. We use BCX70's and BAV99's, but they're just part
numbers, like 2N7002 is a part number. What's wrong with 2N?

"Pro-Electron" sounds kind of hokey to me. Are there any European
semiconductor companies left?

A mention of NFB might come in handy unless he's looking for 10%+ THD.

I'd imagine the emitter follower he's suggesting will be pretty good,
especially if the pulldown resistor is replaced with a current sink.
It will need a stiff drive, which is why I suggested an opamp.

John

 

[John Fields]

On Tue, 14 Oct 2008 23:15:19 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

Rich Grise wrote:

Eeyore wrote:
"olivier.scalbert@algosyn.com" wrote:

I want to do a small class-A music amplifier + preamp. I want to find
the best trade-off between simplicity and sound quality.

Stop mucking about with stuff you don't understand and simply buy a modern
hi-fi amp.

Graham, don't be a dork. The guy wants to _BUILD_ stuff! He needs to be
encouraged - the "let's build it and see how it works" mentality is all
too rare these days.

I agree with the principle but it seems he hasn't done his homework first.

---
Really?

He did enough homework to, in the real world, build an amplifier that
works, and all you can do is spew destructive criticism in order, it
seems, to denigrate his achievement.

Why?

JF

 

[John Larkin]

On Tue, 14 Oct 2008 17:18:39 +0200, Olivier Scalbert
<olivier.scalbert@algosyn.com> wrote:

mrdarrett@gmail.com wrote:



Come now Graham, he didn't mention he wants to become an EE... why be
so mean?

Olivier, why not try this one?
http://diyaudioprojects.com/Solid/ZCA/ZCA.htm

2SK1058 lateral mosfets can be hard to find however.

Michael

Thanks for the link Michael.
I do not want to become EE !
At least good EEs should respect IEEE Code of Ethics (point 5).
http://www.ieee.org/portal/pages/iportals/aboutus/ethics/code.html

;-)

Olivier

11. To sequester technical knowledge in journals, defended by
deliberately obscure abstracts, readable at great expense, the revenue
therefrom going to the IEEE, whether the paper turned out to be useful
or not.

John

 

[Tim Wescott]

Eeyore wrote:

Olivier Scalbert wrote:

Eeyore wrote:
Olivier Scalbert wrote:
john jardine wrote:
For a starter, increase C1 to 1000uF. 'T'll get the response down to about
20Hz.

Thanks !
Done.
I will try to find high quality capacitors later ...
The 'quality' of capaciors is an entire irrelevance with something so primitive.
In fact it's almost a complete irrelevance completely unless you buy Asian junk.

I take it you've been 'Audiophooled' by reading magazines written by wholesale
fraudsters. Audiophile was it ?

Graham (pro-audio designer since 1971)
Graham, why are you so aggressive with me ?
What is your problem ?

I am not being aggresive. I'm teaching you some valuable facts.


I have read it in Farnell catalog.

That's called marketing. Nor is the Farnell catalgue a textbook, despite its other
excellent uses. Do you think the CDs or whatever you listen to were produced on
equipment using these stupid caps ? I can tell you for a fact because I design such
equipment that there's not a hope in hell real designers take these audiophool pieces
of junk seriously.

Graham

WHAT!!!

You mean they don't dip every bit of kit into LN2 at least once before
recording a track???

And they don't use gold plated wall sockets?

And they don't wrap their cable ends in raw silk?

And they don't spin their CDs on platters that have been specially
weighted to increase their rotational inertia?

This would explain why none of my CDs come already treated with magic
green marker around the rim (to keep the light from leaking out, don'cha
know).

Oh, the world is a cold place...

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[John Larkin]

On Tue, 14 Oct 2008 23:15:19 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

Rich Grise wrote:

Eeyore wrote:
"olivier.scalbert@algosyn.com" wrote:

I want to do a small class-A music amplifier + preamp. I want to find
the best trade-off between simplicity and sound quality.

Stop mucking about with stuff you don't understand and simply buy a modern
hi-fi amp.

Graham, don't be a dork. The guy wants to _BUILD_ stuff! He needs to be
encouraged - the "let's build it and see how it works" mentality is all
too rare these days.

I agree with the principle but it seems he hasn't done his homework first. His
present course of action is more likely to involve learning how to let the magic
smoke out. So I have directed him here ....
http://www.dself.dsl.pipex.com/ampins/ampins.htm

Where he will find a wealth of first class info.

Graham

The class A emitter follower is not a bad initial learning experiment,
and has some interesting variants. What's the point of just copying
old circuits? That's not design.

John

 

On Oct 14, 3:08 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:

Olivier Scalbert wrote:
mrdarr...@gmail.com wrote:

Come now Graham, he didn't mention he wants to become an EE... why be
so mean?

Olivier, why not try this one?
http://diyaudioprojects.com/Solid/ZCA/ZCA.htm

2SK1058 lateral mosfets can be hard to find however.

Michael

Thanks for the link Michael.
I do not want to become EE !
At least good EEs should respect IEEE Code of Ethics (point 5).
http://www.ieee.org/portal/pages/iportals/aboutus/ethics/code.html

I agree with it totally. To ecourage you to build shitty circuits would be
grossly negligent.

If you want to learn about audio amplifiers, some excellent resources can
be found here ....http://www.dself.dsl.pipex.com/ampins/ampins.htm

Graham

Graham,

What's your take on this low-TIM amplifier?

http://users.ece.gatech.edu/~mleach/lowtim/

Michael

 

[Eeyore]

mrdarrett@gmail.com wrote:

Eeyore wrote:
Olivier Scalbert wrote:
mrdarr...@gmail.com wrote:

Come now Graham, he didn't mention he wants to become an EE... why be
so mean?

Olivier, why not try this one?
http://diyaudioprojects.com/Solid/ZCA/ZCA.htm

2SK1058 lateral mosfets can be hard to find however.

Michael

Thanks for the link Michael.
I do not want to become EE !
At least good EEs should respect IEEE Code of Ethics (point 5).
http://www.ieee.org/portal/pages/iportals/aboutus/ethics/code.html

I agree with it totally. To ecourage you to build shitty circuits would be
grossly negligent.

If you want to learn about audio amplifiers, some excellent resources can
be found here ....http://www.dself.dsl.pipex.com/ampins/ampins.htm

Graham,

What's your take on this low-TIM amplifier?

http://users.ece.gatech.edu/~mleach/lowtim/

Doesn't look anything special. Besides I thought TIM had been slung out the
window by now as a nebulous concept.

Anything using devices as ancient and expensive as 2N5416s should be looked at
warily too. They were good devices 30 years ago.

Graham

 

[Eeyore]

Bret wrote:

Eeyore wrote:
Olivier Scalbert wrote:
mrdarrett@gmail.com wrote:

Come now Graham, he didn't mention he wants to become an EE... why be
so mean?

Olivier, why not try this one?
http://diyaudioprojects.com/Solid/ZCA/ZCA.htm

2SK1058 lateral mosfets can be hard to find however.

Michael

Thanks for the link Michael.
I do not want to become EE !
At least good EEs should respect IEEE Code of Ethics (point 5).
http://www.ieee.org/portal/pages/iportals/aboutus/ethics/code.html

I agree with it totally. To ecourage you to build shitty circuits would be
grossly negligent.

If you want to learn about audio amplifiers, some excellent resources can
be found here ....
http://www.dself.dsl.pipex.com/ampins/ampins.htm

Graham

What about point 7 ?

Yes I was doing that too with the bluntness it deserved. Hopefully the OP will
have disovered he's not so much barking up the wrong tree but actually in
completely the wrong forest.

Graham

 

[Eeyore]

John Fields wrote:

Eeyore wrote:
John Fields wrote:
Eeyore wrote:
John Fields wrote:

Just simple facts John.

Graham

---
You're a goddam liar.

You know very well that this is seb and that instead of just putting the
guy down by puffing yourself up as an "expert" (implying that he's a
virtual nonentity) you should be helping him understand where his
deficiencies lie, like Larkin did.

But no, you always have to try to make yourself feel important by trying
to make it seem like everyone is less important.

JF

I have given him a link to a far far better site.
http://www.dself.dsl.pipex.com/ampins/ampins.htm

---
After the fact.

I was very occupied earlier. You see I came back to the thread though.

Graham

 

[Eeyore]

John Larkin wrote:

Eeyore wrote:
John Larkin wrote:
Olivier Scalbertwrote:
Eeyore wrote:

Stop mucking about with stuff you don't understand and simply buy a modern
hi-fi amp. Power amps are a real speciality (especially if you want them
to be stable). It's no place for a beginner.

Do you understand stabilty criteria for example. What's a Bode plot ? etc

Graham (designer of stable pro-audio power amps since 1980)

I have studied Bode, Nyquist, Smith diagrams, Z, Laplace, Fourier
transformations and their digital implementations, ...

So I think I can read technical answers to my "beginners" questions.

Oh, by the way, I must admit that I have miss the training "how to
become arrogant".

Hey, this is usenet. It selectively attracts the willfully ignorant,
the arrogant, and the pain sluts who crave public humiliation.

Why not drive the base of your darlington with an opamp?

The BC546 is far too tiny to drive a 2N3055 intelligently. It's TO-92 FFS but you
Americans aren't so familiar with our European (Pro-Electron) devices are you ?

Of course we aren't. We use BCX70's and BAV99's, but they're just part
numbers, like 2N7002 is a part number. What's wrong with 2N?

Nothing whatever, along with 2SA, SB, SC, SD, SJ and SK either. And sone Non - Jedec,
Jeida or Pro-Electron devices that are 'house parts'.

"Pro-Electron" sounds kind of hokey to me. Are there any European
semiconductor companies left?

NXP, STM, Infineon, ARM ring any bells ?

A mention of NFB might come in handy unless he's looking for 10%+ THD.

I'd imagine the emitter follower he's suggesting will be pretty good,

Not that brilliant. One schematic I saw was no emitter follower.

especially if the pulldown resistor is replaced with a current sink.
It will need a stiff drive, which is why I suggested an opamp.

Which'll probably kill the BC546 ! They're only good for about 625mW @ 25C ambient.

Graham

 

[Eeyore]

John Larkin wrote:

Eeyore wrote:
Rich Grise wrote:
Eeyore wrote:
"olivier.scalbert@algosyn.com" wrote:

I want to do a small class-A music amplifier + preamp. I want to find
the best trade-off between simplicity and sound quality.

Stop mucking about with stuff you don't understand and simply buy a modern
hi-fi amp.

Graham, don't be a dork. The guy wants to _BUILD_ stuff! He needs to be
encouraged - the "let's build it and see how it works" mentality is all
too rare these days.

I agree with the principle but it seems he hasn't done his homework first. His
present course of action is more likely to involve learning how to let the magic
smoke out. So I have directed him here ....
http://www.dself.dsl.pipex.com/ampins/ampins.htm

Where he will find a wealth of first class info.

The class A emitter follower is not a bad initial learning experiment,
and has some interesting variants. What's the point of just copying
old circuits? That's not design.

A Class A emitter follower ISN'T an old circuit ?

He'd do infinitely better with a complementary Class A output stage. Then he can
learn how the standing bias changes it from A through AB to pure B or even C ! And
listen to the effect as he twiddles the bias pot.

Graham

 

[Eeyore]

John Fields wrote:

Eeyore wrote:
Rich Grise wrote:
Eeyore wrote:
"olivier.scalbert@algosyn.com" wrote:

I want to do a small class-A music amplifier + preamp. I want to find
the best trade-off between simplicity and sound quality.

Stop mucking about with stuff you don't understand and simply buy a modern
hi-fi amp.

Graham, don't be a dork. The guy wants to _BUILD_ stuff! He needs to be
encouraged - the "let's build it and see how it works" mentality is all
too rare these days.

I agree with the principle but it seems he hasn't done his homework first.

---
Really?

He did enough homework to, in the real world, build an amplifier that
works, and all you can do is spew destructive criticism in order, it
seems, to denigrate his achievement.

I was doing better in my teens because I learnt about real practical circuits.

Graham