John Curl's Blowtorch preamplifier

[john curl]

I virtually 'invented' it. It comes from being able to think 'upside down'.

 

[stinius]

I virtually 'invented' it. It comes from being able to think 'upside down'.

In amps maybe, but I don't think you invented the symmetry?

Stinius

 

[stinius]

I virtually 'invented' it. It comes from being able to think 'upside down'.

I like the way of thinking.

Stinius

 

[stinius]

John

Did you find the resistor in the servo on the JC-2 that you said shouldn't be there?
I can't find it.

Stinius

 

[Joshua_G]

I don't think I will live that long, I am starting to feel 2/3 of a century old, truly. That's why you 'critics' should stop picking on me.

Dear John, please don't fret – we are about the same age …

 

[Joshua_G]

I virtually 'invented' it. It comes from being able to think 'upside down'.

Sometimes, looking upside down gives a fresh view of the world …

 

[john curl]

It matters with the JC-2, but not the Blowtorch, go figure. (The resistor, that is.)

 

[lineup]

I don't think I will live that long, I am starting to feel 2/3 of a century old, truly.

Mother lived 85, father lived 73. I hope I do not have to live 100 years.
I have not much hope this earth will be very nice place in 2051
... wonder what the popular music will be like ... but fear the worst

 

[Joshua_G]

It matters with the JC-2, but not the Blowtorch, go figure. (The resistor, that is.)

For anyone wishing to understand the circuit, not copy it – it shouldn't matter much, knowing there is a possible extra resistor.

 

[Joshua_G]

Mother lived 85, father lived 73. I hope I do not have to live 100 years.
I have not much hope this earth will be very nice place in 2051
... wonder what the popular music will be like ... but fear the worst

 

[stinius]

It matters with the JC-2, but not the Blowtorch, go figure. (The resistor, that is.)

John
It was about the JC-2 I asked, you said it was one resitor to
much on the shematic (servo), you also said that you should come back and tell us which resistor it was.
I can have a closer look, but at the momont I don't find that resistor.

Stinius

 

[stinius]

For anyone wishing to understand the circuit, not copy it – it shouldn't matter much, knowing there is a possible extra resistor.

Joshua

This has nothing to do about copying, it's just a discussion, anyway if you have seen the schematic it's not showing anything exept the topology.

I have not asked John to show any scematics, just to talk about the topology.

Stinius

 

[john curl]

With a negative feedback circuit, it matters. With the Blowtorch (open loop) it doesn't matter.

 

[stinius]

John

Is it R60 ?

Stinius

 

[MikeBettinger]

I virtually 'invented' it. It comes from being able to think 'upside down'.

Sometimes, looking upside down gives a fresh view of the world …

Although, at the time, no one gets it and you just look like an idiot (looking at the world in a way that they can't comprehend) (backed by the theory their education fortified them with)….

I know, I know, but I gotta do something for entertainment...

 

[jan.didden]

Mother lived 85, father lived 73. I hope I do not have to live 100 years.
I have not much hope this earth will be very nice place in 2051
... wonder what the popular music will be like ... but fear the worst

Funny. I wish I could live another 100 years, would give an arm for it. I find the world so fascinating that I want to know how it looks in 50, 100, 500 years. Too bad it won't happen....

Jan Didden

 

[lineup]

My 'signature' is the flower pattern.
I remember back in 1974 showing my future wife what I did. She played the violin at the Institute, but I just seemed to 'hang around'.
I showed her my schematics and presented them as a pattern, rather than just a function.
I suggested to her that it looked like a flower pattern, at the time, or 4 quadrant symmetry.

Nelson Pass likes symmetry in circuits, too.
He sometimes uses the english expression aestethic circuit.
In swedish we call it estetisk[/b].
When something is appealing to our sense for beauty.


I wrote & posted this little mini essay in June 2008,
on the subject: Beauty, Symmetry & Aestethic Circuits

Nevertheless, this circuit is, like Nelson sometimes puts it
so well

AESTETHIC

this means a circuit is not necessarily absolute best hifi
what it means
is more
it is a circuit of beauty & symmetry in idea

Often we human percept symmetry as being 'beautiful', in our eyes/minds.
'Top models' beautiful faces are most often very symmetrical.

Our conception of BEAUTY.

This has been explained as:
Good symmetry signals Good Health.

While asymmetry in nature can signal bad DNA or un-healthy individuals.
.

 

[lineup]

Further interesting ....
... the word audio is a relative of aesthetic

Aesthetic

This word comes from Greek aisthetikos "perceptual",
which is the adjective derived from the verb aisthesthai "perceive".

The adjective form of the Greek, aisthetikos,
arrived in Europe as modern Latin aestheticus,
and it was first used in German philosopher Immanuel Kant's (1724-1804) works (in the form asthetisch), where it meant perceptual".
However, in 1750, A.T. Baumgarten, examining the theory of beauty, used the word to title his work: Aesthetica. It was his choice of the word that exposed it to wider usage and gave it its current meaning.

Interestingly, Latin audire "hear"
is related to the verb aisthesthai,
and therefore all of the English descendants of audire (audible, auditorium, etc.)
are distant cousins of aesthetic.

 

[john curl]

I spent years in an 'attic' devising these 4 quad symmetry circuits. They did not just 'fall off a shelf' and I did it so that the circuit would try to correct its errors, before feedback was applied, if at all.

 

[jan.didden]

John,

I am sure that it didn't come from itself. For us, with the great benefit of hindsight, it all seems so obvious. But anyone who has ever tried to think up something that hasn't been done before knows how very, very hard it is.

And after you've done it, others run with it, point out even better versions and come up with improvements, real or perceived. That's hard to swallow, but that's life.

Jan Didden