Negative Feedback in triodes forgotten?

[Patrick Turner]

Seems like rec.audio.tubes has become the place where
endless and probably entirely pointless discussions
about world politics and air travel terrorists have become the main
focus of attention, so trying to continue on about NFB in triodes
makes me feel like a like a voice in the wilderness.

Of world terror I can say is that it is very unlikely anyone is going to
die
by the actions of a "freedom fighter", unless you live in Iraq, and in
downtown Bagdad.

Far more likely is that you'll die screaming in agony in a car wreck,
industrial accident, or from a fight with cancer or heart disease
helped along by sitting on your arse typing BS into a computer all day.

The terrorists are NOT reducing everyone's
life expectancy in the US, Oz, or the UK very much so why discuss it
endlessly
when you have almost no control at all about any outcome that
is determined by our nation's government forces and the 'powers or
evil'?

I don't have the time to waste bull****ting on and on about world
politics
and the wars and the angst around the globe.
**** has happened, is happening, and will happen again, for sure.
That's about all I need to know.


Meanwhile, last week a few people still seemed unconvinced about
whether or not there was indeed NFB within a triode.

I had a lot to say about it but received a parsimonious response from
the group.
I can assume that few posters have done any independant research on the
the subject.

My position is clear; NFB exists in a triode. Nothing to be ashamed
about imho.
I take it for granted, and happily use triodes without including the
applicable
NFB equations in amplifiers I build with triodes because we can consider
the triode a
3 terminal device and its not necessary for design purposes to
really know all about the modelling between the 3 terminals, cathode,
grid, and anode,
since all we really need is µ, Ra and gm.

Patrick Turner.

[Chris Hornbeck]

On Mon, 04 Sep 2006 04:54:26 GMT, Patrick Turner
> wrote:

>**** has happened, is happening, and will happen again, for sure.
>That's about all I need to know.

Hear, hear.

>I take it for granted, and happily use triodes without including the
>applicable
>NFB equations in amplifiers I build with triodes because we can consider
>the triode a
>3 terminal device and its not necessary for design purposes to
>really know all about the modelling between the 3 terminals, cathode,
>grid, and anode,
>since all we really need is µ, Ra and gm.

Hear, hear.

Much thanks, as always,

Chris Hornbeck
"History consists of truths which in the end turn into lies,
while myth consists of lies which finally turn into truths."
- Jean Cocteau

[[email protected]]

Patrick Turner wrote:
> My position is clear; NFB exists in a triode. Nothing to be ashamed
> about imho.
> I take it for granted, and happily use triodes without including the
> applicable
> NFB equations in amplifiers I build with triodes because we can consider
> the triode a
> 3 terminal device and its not necessary for design purposes to
> really know all about the modelling between the 3 terminals, cathode,
> grid, and anode,
> since all we really need is µ, Ra and gm.
>
> Patrick Turner.


Hi RATs!

Sigh. It is even more simple, or less complex. We hook up wires and
tubes and transformers and listen to music. Then we change something
and listen some more. Sometimes we try and change it back. As if anyone
could ever go back ...

All our keystrokes into the network give us the joy of intellectual
power, which combined with lucky timing and adequate cash will get you
a cup of coffee or bottle of H2O.

It is fun listening to Music. Even the little bits sampled in
recordings. Poking keys on keyboards is not exactly in the same league
of human endeavor. Some of us enjoy playing with tubes and listening to
Music. Some of us enjoy ****ing with people's minds. It is a big
Internet, it doesn't matter what we truly believe or anything. It is
the thing to do this week. I enjoy listening to recordings and playing
God with components. It is not required that anyone do anything similar
to type your soul and savoir faire into this mix. We are just lunatics
with cheap computers and time on our hands, if no ideas nor ideals in
our bleak estates.

Terrorism is whatever we imagine it is. Life is often terrifyingly
boring. Listening to Music can be dead stupid as well.

Half a century ago, the joke was: "Mixed Blessing is getting a room
mate in College that has a ten thousand dollar stereo system and a
record collection of exclusively Donnie and Marie."

Nothing changes. Poor people and rich people think they are luckier
than each other. Perhaps we are all luckier than everybody else.
Wouldn't that be the Ultimate Bringdown?

We enjoy seeing stupid **** on the screen. Ours or yours. Mox nix.

Bedlam is only annoying if you are caught in this fishnet of fantasy.
Otherwise, it is just fun to **** off the bridge and hope the idiots in
the boats below are not armed, or at least not very good shots.

No danger, apparently. Just the sound of silence.

Man is the measure of all things. Sigh.

Happy Ears!
Al

[Andre Jute]

Patrick Turner wrote:
> Seems like rec.audio.tubes has become the place where
> endless and probably entirely pointless discussions
> about world politics and air travel terrorists have become the main
> focus of attention,

Blame Poopie.

> so trying to continue on about NFB in triodes
> makes me feel like a like a voice in the wilderness.

St Patrick of the wild honey from desert wasps? Be careful you don't
get stung.

> **** has happened, is happening, and will happen again, for sure.
> That's about all I need to know.

Actually, I know little something more than you do, though I don't
pretend it is actually helpful. One guy can, if he handles it right,
start big **** rolling. One guy, no matter how right he handles it, can
stop only small **** rolling. It takes takes decades to stop big ****
rolling. That's why mature democracies rightly fear demagogues.

> Meanwhile, last week a few people still seemed unconvinced about
> whether or not there was indeed NFB within a triode.

Forget the crusade, Patrick. I've told them, you've told them. If they
don't want to be educated, that's their lookout.

> I had a lot to say about it but received a parsimonious response from
> the group.

In addition to the considerations above, NFB inside a triode appears to
be a matter of faith. People are entitled to their wrong beliefs, no
matter how dumb and wrong, as long as they don't try to enforce them on
others. I don't care if they believe silicon is superior to tubes for
audio, as long as they do it elsewhere. But there are few enough tubies
for me not to pick a knockdown and dragout with them over what they
want to believe happens inside a triode, especially when we are all
agreed on the beneficial effect at the speaker of whatever it is that
happens inside the triode.

> I can assume that few posters have done any independant research on the
> the subject.

I showed them the thought experiment, you added the technical details
of implementing it on the bench for those who require experimental
confirmation, I gave them references to other ways of reaching the same
conclusion. My conscience is clear: I did everything that is required.
So should yours be: you've done more.

> My position is clear; NFB exists in a triode. Nothing to be ashamed
> about imho.
> I take it for granted, and happily use triodes without including the
> applicable
> NFB equations in amplifiers I build with triodes because we can consider
> the triode a
> 3 terminal device and its not necessary for design purposes to
> really know all about the modelling between the 3 terminals, cathode,
> grid, and anode,
> since all we really need is µ, Ra and gm.

Exactly. If you add that we know from experience that triodes sound
better (for which there must be a reason!), that is a full, satisfying,
picture. The details about NFB are trimmings, at least between friends.

> Patrick Turner

You're smarter than you look, pal. Send a hundred bucks or I'll say
that in your pub, get you beaten up by the yobs for being different.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[Andre Jute]

wrote:

> Man is the measure of all things. Sigh.

"I prefer a steel ruler" -- Engineer

Andre Jute

[Patrick Turner]

Snip the empathy/sympathy bits, lest the yobs find out
too much.....

>
>
> You're smarter than you look, pal. Send a hundred bucks or I'll say
> that in your pub, get you beaten up by the yobs for being different.

Hmm, I don't spend any time in pubs these days but I do hang out
in cafes to play chess.

At least the the chess dudes don't give a rat's if one is different...

But lucky I got home last sunday after the bruisings with knights, bishops and
queens.

The Laser had a flat battery after being left alone with everything turned off
over night,
and I discovered a 2 amp current flow when 12V was applied to the disconnected
red lead of the battery
with all things turned off. I removed all fuses one by one to see which
circuit
was drawing 2A with the Ign sw turned off but drew a blank, which means the
only thing left
is the alternator, and if that's OK I have not a clue what is offering 6 ohms
resistance to the
red leads coming from the battery.
Nothing about such a fault in the workshop manual of course.....

But I can survive awhile with a pushbike of course.

So will you pay me $100 for not making so much greenhouse gas
until I get my car fixed?

Carbon Trading :-0.

I reckon carbon issues loom as a far bigger problem in the fullness of time.
Nobody wants to really talk about it, let alone do anything real, they just
wanna
bigga air con.

Patrick Turner.