[Ian Bell]

Patrick Turner wrote:


However, its to be remembered that A or A' are negative if Vg is +ve.

This would make the equation really for A' = -A / (1 + [ -A x ß ] )

This would not work out if the basic ohms law method I began with is
viewed as the practical truth.

So is ß really a -ve value? so that -A x -ß is a positive quantity
because two -ve values are multiplied?


This is all explained in excruciating detail in the Radiotron Designers
Handbook the 1953 edition of which is readily available on the net.

Ian

[Patrick Turner]

Ian Bell wrote:

Patrick Turner wrote:


However, its to be remembered that A or A' are negative if Vg is +ve.

This would make the equation really for A' = -A / (1 + [ -A x ß ] )

This would not work out if the basic ohms law method I began with is
viewed as the practical truth.

So is ß really a -ve value? so that -A x -ß is a positive quantity
because two -ve values are multiplied?


This is all explained in excruciating detail in the Radiotron Designers
Handbook the 1953 edition of which is readily available on the net.


Indeed, and it is excruciating.

I just like formulas that just work simply, and where you don't have to
worry about the
signage in front of a gain or ß figure.
Guess I just failed in my math exam eh.

I have a paper folder which contains only formulas that work.
All the others that didn't seem to work too good never made it into my
folder.
I must go through it one day and
copy it out for the web; its the one very useful missing thing from my
website,
although there are a lot of formulas already there, all derived from
RDH4, Wireless World articles,
and extracts from other hard cover books in my little library of
mostly old electronics from the 1950s.
They were mostly chucked out in 1960 when solid state finally became
reliable and cheap.
Then the books seemed to stop being written, maybe ppl thought,
"oh well, no use writing a book if its all going to become obsolete in 5
years."
but a little later, things became obsolete in 18mths, and nobody wrote
nuthin,
and any little thing written was considered to be worth private money.
I only have a very hazy idea of what signal flows occur in my PC.But I
digress, again....

The math serves the understanding of the concept of FB and what it does,
and provides quantified real answers.

The FB does not exist so we can have exact mathematics, and beauty in
mathematical
expressions; the phenomena of simple motion were not created
just to allow a nice set of math to be revealed by Newton.

There is nearly always a perverse reason why we could say something
exists.

And there is no answer to why everything exists at all.

Patrick Turner.



Ian

[Ian Bell]

Patrick Turner wrote:



Ian Bell wrote:

Patrick Turner wrote:


However, its to be remembered that A or A' are negative if Vg is +ve.

This would make the equation really for A' = -A / (1 + [ -A x ß ] )

This would not work out if the basic ohms law method I began with is
viewed as the practical truth.

So is ß really a -ve value? so that -A x -ß is a positive quantity
because two -ve values are multiplied?


This is all explained in excruciating detail in the Radiotron Designers
Handbook the 1953 edition of which is readily available on the net.


Indeed, and it is excruciating.

I just like formulas that just work simply, and where you don't have to
worry about the
signage in front of a gain or ß figure.
Guess I just failed in my math exam eh.

I have a paper folder which contains only formulas that work.
All the others that didn't seem to work too good never made it into my
folder.
I must go through it one day and
copy it out for the web; its the one very useful missing thing from my
website,
although there are a lot of formulas already there,

Seems to me all the really useful ones are there already.

Ian

[Patrick Turner]

Ian Bell wrote:

Patrick Turner wrote:



Ian Bell wrote:

Patrick Turner wrote:


However, its to be remembered that A or A' are negative if Vg is +ve.

This would make the equation really for A' = -A / (1 + [ -A x ß ] )

This would not work out if the basic ohms law method I began with is
viewed as the practical truth.

So is ß really a -ve value? so that -A x -ß is a positive quantity
because two -ve values are multiplied?


This is all explained in excruciating detail in the Radiotron Designers
Handbook the 1953 edition of which is readily available on the net.


Indeed, and it is excruciating.

I just like formulas that just work simply, and where you don't have to
worry about the
signage in front of a gain or ß figure.
Guess I just failed in my math exam eh.

I have a paper folder which contains only formulas that work.
All the others that didn't seem to work too good never made it into my
folder.
I must go through it one day and
copy it out for the web; its the one very useful missing thing from my
website,
although there are a lot of formulas already there,

Seems to me all the really useful ones are there already.

Yeah, but there is so much to know if you want to know
ALL the reasons for why we do things in amplifiers and analog circuits.

The message is a bit jumbled at my site, and there is no well linked
index.
I should really collate and co-ordinate the material better, and
make room for the formulas that are not there.
There are many concepts to grasp, well, i found I kept getting stuck as
i went along, and continue to do so
all the damn time.

A guy here has got me building a kit for a pair of ESLIIIB speakers from
http://www.eraudio.com.au/index.html

Its slowly working out OK, but because there isn't any response data or
impedance graphs at the
ERA site, I am left wondering what the outcome will be, so I am
furiously testing and calculating
and creating alternative input circuitry and transformer design to make
the
speaker as benign to drive as Quad ESL57 or ESL63. I built the tube amps
that will be used
with these speakers, so the effort must have a good outcome.

I have to say, anyone who does arrive with an ESL design as easy to
drive as the Quad models
really knows his stuff; there must be a very careful juggling of
capacitance values,
voltage ratios in trannies, and the tranny shunt capacitances.
Most ppl tend to make the panel C high, and not worry about the shunt C
of their
step up transformers whose behaviour remains a mystery to most of them.

Proof of the pudding is in the eating,
and maybe by a week or two I will know what the optimum way to set them
up really is.

Some other ESL sites I found of interest are at

http://www.ele.tut.fi/~artoko/audio/...ansformer.html

http://www.justrealmusic.com/content/transformers.htm

http://www.amplimo.nl/index.html?lan...arget=d36.html

For those really wanting a challege to their powers of deduction, try
reading the
original notes about the design of Quad ESL57 by Peter Baxandall.

Peter says what really needs to be said, a true electronic intellectual,
who luckily
was able to convey concepts fluently to anyone rather well, and the
guys behind the URLs above are not quite up there yet.

I'm struggling.

Patrick Turner.



Ian

[Ian Bell]

Patrick Turner wrote:

Yeah, but there is so much to know if you want to know
ALL the reasons for why we do things in amplifiers and analog circuits.

The message is a bit jumbled at my site, and there is no well linked
index.
I should really collate and co-ordinate the material better, and
make room for the formulas that are not there.
There are many concepts to grasp, well, i found I kept getting stuck as
i went along, and continue to do so
all the damn time.


How about organising things along the lines of what you need to know at each
stage of the design. So start with required input and output levels and
impedances, bandwidth and distortion for example. Begin say with a simple
line amp and show how to translate these into valve, topology and component
selections. Then extend to harder designs like RIAA, mic pre and 600
transformer balanced outputs.

A guy here has got me building a kit for a pair of ESLIIIB speakers from
http://www.eraudio.com.au/index.html

Its slowly working out OK, but because there isn't any response data or
impedance graphs at the
ERA site, I am left wondering what the outcome will be, so I am
furiously testing and calculating
and creating alternative input circuitry and transformer design to make
the
speaker as benign to drive as Quad ESL57 or ESL63.

I have a couple of 10 inch Tannoy monitor Golds in very old original Tannoy
infinite baffle cabinets. I love the clarity of the dual concentric design
but the cabinets are boomy and lacking in extreme bass. I would love to
build a pair of good sounding cabinets for them. I have seen complex horn
designs that are way beyond my modest woodworking skills and tools. I was
wondering if one of you cabinet designs could be tweaked for a single
10inch driver?

Ian

[Patrick Turner]

Ian Bell wrote:

Patrick Turner wrote:

Yeah, but there is so much to know if you want to know
ALL the reasons for why we do things in amplifiers and analog circuits.

The message is a bit jumbled at my site, and there is no well linked
index.
I should really collate and co-ordinate the material better, and
make room for the formulas that are not there.
There are many concepts to grasp, well, i found I kept getting stuck as
i went along, and continue to do so
all the damn time.


How about organising things along the lines of what you need to know at each
stage of the design. So start with required input and output levels and
impedances, bandwidth and distortion for example. Begin say with a simple
line amp and show how to translate these into valve, topology and component
selections. Then extend to harder designs like RIAA, mic pre and 600
transformer balanced outputs.

I don't have time for perfection.

Who pays me for the time it takes to reach a more perfect state?

There is a an answer for everyone for 99% of their queries at my website
IF THEY TAKE THE TROUBLE TO LOOK FOR IT.

It was easier for me to explain the priciples, give a few examples, and
then leave everyone to do what they want by applying the principles.

Life is all about applying principles to live, work, or play. I didn't
set out to
spend triple the time I did spend to
make it easier than I have.

I HATE spoon feeding 50 year old guys who cannot learn to think for
themselves,
or who have forgotten to question and answer the questions themselves.


A guy here has got me building a kit for a pair of ESLIIIB speakers from
http://www.eraudio.com.au/index.html

Its slowly working out OK, but because there isn't any response data or
impedance graphs at the
ERA site, I am left wondering what the outcome will be, so I am
furiously testing and calculating
and creating alternative input circuitry and transformer design to make
the
speaker as benign to drive as Quad ESL57 or ESL63.

I have a couple of 10 inch Tannoy monitor Golds in very old original Tannoy
infinite baffle cabinets. I love the clarity of the dual concentric design
but the cabinets are boomy and lacking in extreme bass. I would love to
build a pair of good sounding cabinets for them. I have seen complex horn
designs that are way beyond my modest woodworking skills and tools. I was
wondering if one of you cabinet designs could be tweaked for a single
10inch driver?

For good bass you have to build good cabinets. I don't like infinite
baffles,
or closed boxes. Usually speakers which are unported are said to be
'fast'
and have good transients but usually if the box has no port, the makers
didn't want
to make the box big enough, nor want to go to the expense of boring one
hole,
and all thet say about closed box is BS and simply means
there isn't much low bass. Its unusual you say infinite cabs are boomy,
usually ported boxes get blamed for that and its because the speaker
is too big bor its ported box, and a 6db peak at say 80Hz occus before
an 18dB/octave roll off.

I am nearly always happy if the box = VAS for the driver which usually
means
a box 2 or 3 times the volume that it came in from the makers,
who like to use BS to happy ppl up, rather than supply the wood
required.

I can also measure a driver's TS parameters using formulas from David
Weems and a standard
test cabinet. Then I use WinISD , a box program for the volume and port
details.

Its all a lot of work, and you must be practical, and energetic about it
or else nothing happens.

Patrick Turner.

Ian

[Ian Bell]

Patrick Turner wrote:



Ian Bell wrote:

Patrick Turner wrote:

Yeah, but there is so much to know if you want to know
ALL the reasons for why we do things in amplifiers and analog circuits.

The message is a bit jumbled at my site, and there is no well linked
index.
I should really collate and co-ordinate the material better, and
make room for the formulas that are not there.
There are many concepts to grasp, well, i found I kept getting stuck as
i went along, and continue to do so
all the damn time.


How about organising things along the lines of what you need to know at
each stage of the design. So start with required input and output levels
and impedances, bandwidth and distortion for example. Begin say with a
simple line amp and show how to translate these into valve, topology and
component selections. Then extend to harder designs like RIAA, mic pre
and 600 transformer balanced outputs.

I don't have time for perfection.

Who pays me for the time it takes to reach a more perfect state?


Noone. You do it out of the goodness of your heart.

There is a an answer for everyone for 99% of their queries at my website
IF THEY TAKE THE TROUBLE TO LOOK FOR IT.


I agree. It was YOU who suggested reorganising/updating it.

Ian