[paul packer]

On Wed, 13 Sep 2006 11:43:36 +1000, "Phil Allison"
wrote:


i'd call that a massive generalisation.


** I'd call YOU a massive ****WIT !!!


But since you've called everyone that at one time or another, it
probably doesn't mean much.

[Patrick Turner]

Phil Allison wrote:

"Patrick Turner"

** Tube amps are just so compromised by that damn great lump of iron
hanging
off the output.

You would not believe the massive phase shift these boat anchors exhibit
at
both ends of the audio band.

Totally prevents using a **decent amount** of loop feedback or the whole
amp becomes HORRIBLY unstable.


Phil, I do beg to differ.

** Like the true ****head you are.

Because the amps work with so much class A more than a total of 16dB of
local
and global NFB is not needed.

** 16 dB of loop NFB is all that can be applied.

At mid band frequencies.

Backs up what I said completely.

Backing your self up without any respect to what anyone else says is exactly
your style and prooves
your debating methods are quite inadequately convincing to anyone with a brain.

I routinely make OPTs which allow 40dB+ of applied global NFB at the mid
frequency.
But there is a stablity margin of at least 15 dB at 20Hz and 20kHz,
so that at least 30 dB of NFB can be applied at the end of the AF band.
Stabilizing networks allow any vaue of capacitance tpo be connected across the
output terminals
without a resistive load and stbility is maintained.
There is NO NEED to apply any more NFB than I do in a tube amp and that is the
reason
why I don't, and its not because I cannot apply any more than 16 dB.

There have been many amps with inadquate amounts of LP and hube amounts of
leakage L
and shunt C and these will produce a small margin of stability with NFB but I
don't make
OPTs like the crummy types fitted to so many commercially made products such as
old Leaks etc.

Save the next hissy fit for someone else Phil because calling names doesn't
work, except
to make you look exactly what you have called me.
This time YOU are incorrect, so get used to it.

And when replying, try not to snip so much relevant information the group
may be interested in.

Patrick Turner.






....... Phil

[Patrick Turner]

Phil Allison wrote:

"Ruud Broens"
:
: ** Tube amps are just so compromised by that damn great lump of iron
hanging
: off the output.
:
: You would not believe the massive phase shift these boat anchors exhibit
at
: both ends of the audio band.
:
: Totally prevents using a **decent amount** of loop feedback or the
whole
: amp becomes HORRIBLY unstable.
:
:
i'd call that a massive generalisation.

** I'd call YOU a massive ****WIT !!!

exibit A sowter U 061,
leakage inductance 86 dB below inductance,
- 0.5 dB 10Hz 42 kHz
controlled hf roll off from 100 kHz
0.05 % THD at 100W, 1kHz, 0.5 % at 22Hz 100W

can you give us the ^massive^ numbers ?

** Where are the * phase shift * numbers - ****wit ??

Lets see them for various load conditions too.

Even the best tube amp designs have only 20 dB of loop NFB.

You are Wrong Again and 26dB was a routine amount of NFB used in Mullard 520
with a Partridge OPT and if you study the amps by ARC and CJ and many other
names
you will find they use lots more than 20 dB of global NFB.
The top brand names tried often to have their products measure as well as
possible because the market
amoung conservative middle aged men is one where many of these guys
don't feel comfortable with lousy measurements regardless of the subjective
perceptions which are often beyond their capability to make with any meaning or
accuracy.
0.05% THD at a kHz at 1 dB below clipping at 50 watts meant that listening
levels
gave around 0.01% THD.... AND... very low phase shift.

There was a strong urge to get the measured thd below 0.1% at clipping in many
tube amps
and to get the phase shift less than +/- 10 degrees at each end of the AF band.

Check out the original design data by D.T.N Williamson and McIntosh.

Not much to whinge about.

Patrick Turner.



....... Phil

[Phil Allison]

"Patrick Turner"


** Where are the * phase shift * numbers - ****wit ??

Lets see them for various load conditions too.

Even the best tube amp designs have only 20 dB of loop NFB.

You are Wrong Again and 26dB was a routine amount of NFB used in Mullard
520
with a Partridge OPT and if you study the amps by ARC and CJ and many
other
names


** What nit picking ********.

SS amps typically use over 60 dB of NFB to *eliminate* harmonic distortion.

Unlike any tube amp with an OT, negative feedback extends over the range
from DC to MHz .




........ Phil

[Phil Allison]

"Patrick Turner" = a totally psycho, transformer winder freak.



Here is what originally I wrote:

----------------------------------------

" Tube amps are just so compromised by that damn great lump of iron hanging
off the output.

You would not believe the massive phase shift these boat anchors exhibit at
both ends of the audio band.

Totally prevents using a **decent amount** of loop feedback or the whole
amp becomes HORRIBLY unstable. "

----------------------------------------

The phrase " **decent amount** " is to be defined in relation to SS amp
norms.

Not bloody tube amp norms, since that begs the question - you imbecile !!


No tube amp with an OT has a damping factor anything like 1000 from DC to
5KHz.

No tube amp with an OT has a THD anything like 0.002 % from DC to 20 KHz,
for life.

And the reason they DO NOT is because of response and particularly PHASE
SHIFT limitations imposed by the OT.

That is why ** were placed around the phrase " decent amount ".


Now, **** the hell off - you criminal POS.





........ Phil

[Patrick Turner]

Phil Allison wrote:

"Patrick Turner"


** Where are the * phase shift * numbers - ****wit ??

Lets see them for various load conditions too.

Even the best tube amp designs have only 20 dB of loop NFB.

You are Wrong Again and 26dB was a routine amount of NFB used in Mullard
520
with a Partridge OPT and if you study the amps by ARC and CJ and many
other
names

** What nit picking ********.

You made a serious error in your posts which I have pointed out.

At normal listening levels a well made tube amp working in class A has THD
less than 0.02%, ie, a pair of KT88/6550 in PP with 16dB global NFB
and at a watt where max po = 40+ watts.

This THD if it were played through a speaker without the wanted undistorted
signal
would be inaudible, and therefore eliminated.
But of course the ability of people to detect THD is at a threshold 20 dB or
more above
the 0.02% levels.



SS amps typically use over 60 dB of NFB to *eliminate* harmonic distortion.

Yes, and I have built SS amps which have less than 0.01% at 250 watts.
So what? I know of nobody who detects that a better measuring SS amp
has less THD than tube amp of average quality, and where the playing field of
comparison is level, ie,
we are testing a 50 watt SS amp with a 50 watt tube amp.



Unlike any tube amp with an OT, negative feedback extends over the range
from DC to MHz .

There is no NEED for the NFB to extend from DC to MHz.

We can only hear from about 20Hz to 15kHz.

Bandwidth up to MHz can be a real problem because of the inevitable
phase shift of reactive loads so SS amps become unstable at RF insted of at
about between
80kHz and 300kHz for a tube amp if poorly made.
Who cares if a reduced amount of NFB is effective at 20kHz?
The first artifact is the second harmonic at 40kHz.

Virtually all SS amps have enormous open loop gain at say about 500Hz and then
it rolls off
at 6 dB/octave above 500Hz, so the amount of applied FB also rolls off
above 500Hz where indeed the applied global NFB is 60 dB but not at 50kHz where
it is
perhaps 40dB less or more especially if the HF gain has been reduced by a zobel
network
in the input stages.

Nearly all SS amps have an RC Zobel from the output and NFB take off point to
0V
to prevent the follower output stage having too much gain internally.
Then there is usually an L&R series network between the NFB take off and the
load
to prevent the effect of capacitive loads from
causing impossible current levels on transients.
The signal at the speaker is thus slightly indirectly coupled to the amp and
its FB, ie, its filtered,
and the LR can cause a lot of ringing on square waves, rather like the leakage
inductance
causes ring in the similar manner.

In any case THD is NOT eliminated by any amp although it can be reduced below
the noise floor.
Halcro amps get extraordinarily low thd measures of 0.0001% at 200 watts and
declining proportionately
with output voltage so thd cannot easily be measured at a watt.
THis does not mean that all the many amps which measure 10x 100x or 1,000x
times worse
should all be binned.

I just don't hear any huge sonic improvement by reducing THD below 0.02%
and reducing the accompanying and worse problems of IMD.

THD is a rather innocent artifact because most THD products merely add or
subtract
a tiny % to the existing huge number of harmonics in music.
The related IMD products are the real worry because the interaction between
different tones produces tones which are not necessarily harmonic with the
music's
harmonics, and the IMD manifests itself in a kind of grating noise in the
backgound
of the music, something that some SS amps are prone to despite measuring
reasonably
well with THD into an R load with a single tone of 1 kHz.
Pentode amps without NFB sound awful as well if used for repropucing music
accurately,
but not if used as part of the instrument as a musician does; the more
harmonics and artifacts including some mains buzz, and the rock stars think its
great.

Interaction between say 18kHz and 17kHz will produce sum and difference F of
35kHz and 1 kHz. The 1 kHz could be heard if levels were high enough to start
with and the
amp of poor quality, but in music levels of HF are low.

The IMD levels produced in the 1947 Williamson amp when used with any music for
an average level
of 0.5 watts into speakers of the day at 96dB efficient was negligible, and
all the sources had MORE IMD than the amplifier was producing, and probably the
speakers.

If we use a quad of KT88 instead of a pair of lousy KT66 today,
the amp IMD is quite low enough to be inaudible with moderate NFB applied.

If you want to built an amp without any global NFB and use a single triode,
the result can measure within existing known hi-fi standards.

Loop NFB may be used, but it is never been compulsory in triode amps.
It is compulsory with SS amps, since there is no internal NFB within a basic SS
device
like there is in a triode.

Patrick Turner.












....... Phil

[Phil Allison]

"Patrick Turner" = totally psycho, transformer winding room temp cretin


** Where are the * phase shift * numbers - ****wit ??

Lets see them for various load conditions too.

Even the best tube amp designs have only 20 dB of loop NFB.

You are Wrong Again and 26dB was a routine amount of NFB used in
Mullard
520
with a Partridge OPT and if you study the amps by ARC and CJ and many
other
names

** What nit picking ********.

You made a serious error


** What INSANE ********.

The NFB ratio of most SS amps is 60 dB or more !!

Cos there is no damn output transformer to worry about.




........ Phil

[Patrick Turner]

Phil Allison wrote:

"Patrick Turner" = a totally psycho, transformer winder freak.

Here is what originally I wrote:

----------------------------------------

" Tube amps are just so compromised by that damn great lump of iron hanging
off the output.

You would not believe the massive phase shift these boat anchors exhibit at
both ends of the audio band.

Totally prevents using a **decent amount** of loop feedback or the whole
amp becomes HORRIBLY unstable. "

----------------------------------------

The phrase " **decent amount** " is to be defined in relation to SS amp
norms.

Ah, so now to try to gain credibility for your original statements
you invent conditions and definitions AFTER being justifiably
criticised by myself.



Not bloody tube amp norms, since that begs the question - you imbecile !!

No tube amp with an OT has a damping factor anything like 1000 from DC to
5KHz.

There is zero need for DF to be 1,000.

All speakers have a dc component in their DC resistance of crossover coils etc
and thus the series R component will eclipse attempts at betterment
by having the Rout of the amp at 1/1,000 of the speaker load value.

There is no need for Rout to be less than 1/10 of the minimum load value.



No tube amp with an OT has a THD anything like 0.002 % from DC to 20 KHz,
for life.

There is no need for THD to be 0.002%.

If the output level is 2.83Vrms or one watt into 8 ohms,
0.002% is 5.66 uV, and rather hard to hear if played alone into any speaker.
0.2% is only 5.66 mV, and inaudible to most folks.



And the reason they DO NOT is because of response and particularly PHASE
SHIFT limitations imposed by the OT.

SS amps have phase shift at HF and if enough NFB is applied they can go unstable

but at a higher F than with a tube amp.
I have seen plenty of SS amps which displayed oscillations at some RF
because of the applied FB and phase shift.

There is no need to apply much NFB around most well made tube amps
because the open loop BW is usually 10Hz to 50kHz with open loop
phase shift less than +/- 90 degrees at those F, and the THD
is less than 2% at full power open loop.
Therefore with 20dB of NFB the phase shift, response, and THD is all improved by

10 times, and there is no justification to exclude tube amp measurements from
being
OK because they do not comply with YOUR ideas of what constitutes a "decent
amount" .



That is why ** were placed around the phrase " decent amount ".

Your "decent amount" is your own invention to save your hide.

You are sounding worse than Trevor Wilsom when trying to present the facts.



Now, **** the hell off - you criminal POS.

I WILL REMAIN HERE TO CORRECT YOUR BS.

You don't often BS, but when you do, it needs to be pointed out.

Patrick Turner.





....... Phil

[George M. Middius]

Patrick Turner said:

Now, **** the hell off - you criminal POS.

I WILL REMAIN HERE TO CORRECT YOUR BS.
You don't often BS, but when you do, it needs to be pointed out.

What on earth is wrong with this "Phil Allison" person?





--

"Christians have to ... work to make the world as loving, just, and supportive as is possible."
A. Krooger, Aug. 2006

[Phil Allison]

"Patrick Turner" = a totally psycho, transformer winder freak.


Here is what originally I wrote:

----------------------------------------

" Tube amps are just so compromised by that damn great lump of iron hanging
off the output.

You would not believe the massive phase shift these boat anchors exhibit at
both ends of the audio band.

Totally prevents using a **decent amount** of loop feedback or the whole
amp becomes HORRIBLY unstable. "

----------------------------------------

The phrase " **decent amount** " is to be defined in relation to SS amp
norms.

Not bloody tube amp norms, since that begs the question - you ****ING
imbecile !!

No tube amp with an OT has a damping factor anything like 1000 from DC to
5KHz.

No tube amp with an OT has a THD anything like 0.002 % from DC to 20 KHz,
for life.

And the reason they DO NOT is because of response and particularly PHASE
SHIFT limitations imposed by the OT.

That is why ** were placed around the phrase " decent amount ".


Now, **** the HELL OFF -

you damn CRIMINAL PSYCHOPATH





........ Phil

[Phil Allison]

"Patrick Turner"

If the output level is 2.83Vrms or one watt into 8 ohms,
0.002% is 5.66 uV,


** ******** !!

The autistic cretin cannot do basic math.


and rather hard to hear if played alone into any speaker.
0.2% is only 5.66 mV, and inaudible to most folks.


** MORE ********.





....... Phil

[Patrick Turner]

Phil Allison wrote:

"Patrick Turner" = totally psycho, transformer winding room temp cretin


** Where are the * phase shift * numbers - ****wit ??

Lets see them for various load conditions too.

Even the best tube amp designs have only 20 dB of loop NFB.

You are Wrong Again and 26dB was a routine amount of NFB used in
Mullard
520
with a Partridge OPT and if you study the amps by ARC and CJ and many
other
names

** What nit picking ********.

You made a serious error

** What INSANE ********.

The NFB ratio of most SS amps is 60 dB or more !!

Yes I agree with this last sentance.
You imply that 60dB is a great achievement but 40dB would be fine,
or even 20dB if the amp was a in class A.



Cos there is no damn output transformer to worry about.

And none to worry about in a tubed OTL amp either, where
40 db of NFB is commonly used because the Rout is so abysmally high,
and the tubes are forced to work with loads they are not meant to work with
and in class B.

The global NFB around a bjt amp is needed to mainly reduce THD from about
5% at clipping without the global. The crossover Dn and attrocious other
output stage artifacts are
dealt with usually with the emitter follower connection which is local NFB
equal to about 40dB, so in fact a lot MORE total NFB is needed for
an SS amp to force it to measure how they do.

I am not against vast amounts of NFB in SS amps because i find that its so
easy to
use and gain is so abundant and the sound does not suffer from the huge amount
of NFB.
But after having conducted AB tests between the better tube amps AND SS amps
which I have
designed and constructed and as detailed at my website I find that most ppl
have difficulty telling me of any real sonic differences.

I have used only mild NFB in my class A 50 watt mosfet based monoblocs with
OPTs with 10Hz to 300kHz BW as one does in a tube amp
and although THD is 0.2% at 40+ watts, there is no improvement when moving to
a 300 watt amp with 1/100 of the THD, and no OPT.

Many ppl prefer SET and SEUL amps with much more THD over what they find
with better SS amps like Musical Fidelity which sounds so clinical and dull.

I don't worry about the OPT because the ones I make have
extraordinary bandwidth and able to be used with much more NFB than is
required.

Patrick Turner.



....... Phil

[Patrick Turner]

I will not **** off.

Your unjustified criticisms of OPTs has gotten you into hot water.

You have little idea of what is possible with an OPT because you have never
designed and wound one
and are used to the crummy varieties found in guitar amps and budget crap which
cannot sustain
much applied FB.

But in the best brands of h-fi tube amps the OPT bandwidth has been extended
and phase shift reduced to enable an adequate amount of NFB to be applied
to have the amp conform to standard hi-fidelity standards.

Patrick Turner.



Phil Allison wrote:

"Patrick Turner" = a totally psycho, transformer winder freak.

Here is what originally I wrote:

----------------------------------------

" Tube amps are just so compromised by that damn great lump of iron hanging
off the output.

You would not believe the massive phase shift these boat anchors exhibit at
both ends of the audio band.

Totally prevents using a **decent amount** of loop feedback or the whole
amp becomes HORRIBLY unstable. "

----------------------------------------

The phrase " **decent amount** " is to be defined in relation to SS amp
norms.

Not bloody tube amp norms, since that begs the question - you ****ING
imbecile !!

No tube amp with an OT has a damping factor anything like 1000 from DC to
5KHz.

No tube amp with an OT has a THD anything like 0.002 % from DC to 20 KHz,
for life.

And the reason they DO NOT is because of response and particularly PHASE
SHIFT limitations imposed by the OT.

That is why ** were placed around the phrase " decent amount ".

Now, **** the HELL OFF -

you damn CRIMINAL PSYCHOPATH

....... Phil

[Patrick Turner]

Phil Allison wrote:

"Patrick Turner"

If the output level is 2.83Vrms or one watt into 8 ohms,
0.002% is 5.66 uV,

** ******** !!

The autistic cretin cannot do basic math.

You offer no correction, just insults, but OK, I made a slight mistake
in the math.

0.002% is 0.00002 x 2.83V = 56.6 uv, and this would NOT be audible.
0.2% is 0.002 x 2.83V = 5.66 mV, which is correct, no?...
and is also inaudible as would 0.02%, typical for a well made tube amp
at a watt.



and rather hard to hear if played alone into any speaker.
0.2% is only 5.66 mV, and inaudible to most folks.

** MORE ********.

Next time you have a pure sine wave feeding a speaker add 0.2% of 2H or
3H
and see if you hear anything.

These harmonics are usually always the largest present in most amp
artifact list.
but most well made tube amps have 0.02% at 1 watt, which is a loud 90dB
SPL from
most modern speakers and I know you cannot hear that 0.02%.

When you say ******** to me, I hear that you are bull****ting.

Patrick Turner.





...... Phil

[[email protected]]

On Thu, 14 Sep 2006 00:27:37 +1000, "Phil Allison"
wrote:


"Patrick Turner" = totally psycho, transformer winding room temp cretin


** Where are the * phase shift * numbers - ****wit ??

Lets see them for various load conditions too.

Even the best tube amp designs have only 20 dB of loop NFB.

You are Wrong Again and 26dB was a routine amount of NFB used in
Mullard
520
with a Partridge OPT and if you study the amps by ARC and CJ and many
other
names

** What nit picking ********.

You made a serious error


** What INSANE ********.

The NFB ratio of most SS amps is 60 dB or more !!

Cos there is no damn output transformer to worry about.




....... Phil



Plus the fact that a bunch of 500 beta transistors in cascade will give you a
gain in the billions! Most power amps have a voltage gain requirement closer to
10... feedback is necessary if you don't want noisy attenuator circuits...

[paul packer]

On Wed, 13 Sep 2006 10:40:34 -0400, George M. Middius cmndr
[underscore] george [at] comcast [dot] net wrote:



Patrick Turner said:

Now, **** the hell off - you criminal POS.

I WILL REMAIN HERE TO CORRECT YOUR BS.
You don't often BS, but when you do, it needs to be pointed out.

What on earth is wrong with this "Phil Allison" person?


How long have you got, George?

[Car]

paul packer wrote:
On Sat, 9 Sep 2006 15:02:13 +1000, "Phil Allison"
wrote:

"Phil"

You know, I have terminal cancer, and maybe heart problems (waiting for
the results),

** Don't be so modest with your medical boasting -

you also have terminal autism and bi-polar disorder.



but I would rather be me, and dead soon,

** Then we all have something to look forward to.





....... Phil


You have a heart as big as all outdoors, Phil.


Go to: http://www.cancer-coverup.com/fighte...um-science.htm

You may find some hope for your situation, it is your choice.

Good luck.

[Arny Krueger]

"paul packer" wrote in message
...
On Wed, 13 Sep 2006 10:40:34 -0400, George M. Middius cmndr
[underscore] george [at] comcast [dot] net wrote:



Patrick Turner said:

Now, **** the hell off - you criminal POS.

I WILL REMAIN HERE TO CORRECT YOUR BS.
You don't often BS, but when you do, it needs to be pointed out.

What on earth is wrong with this "Phil Allison" person?

How long have you got, George?

Why not start out by telling us what's wrong with George and yourself, Paul?

[Phil Allison]

"paul packer"

What on earth is wrong with this "Phil Allison" person?


How long have you got, George?


** Long enough to telephone NSW Australia ??

Try: 13 Tosca Drive Gorakan

(02) 4392 5924 ...... ask for Gladys


Or if that fails, try

13A Tosca Drive Gorakan,

(02) 4393 9920

and ask for Paul ( aka Edward)



Enjoy............






....... Phil

[paul packer]

On Thu, 14 Sep 2006 22:39:35 +1000, "Phil Allison"
wrote:


"paul packer"

What on earth is wrong with this "Phil Allison" person?


How long have you got, George?


** Long enough to telephone NSW Australia ??

Try: 13 Tosca Drive Gorakan

It's Gorokan, Phil. How many times!!!

(02) 4392 5924 ...... ask for Gladys

And say what? He doesn't know Gladys and neither do you.
For the record, Gladys is my 85 year old widowed mother, and anyone
disturbing her with an unnecessary or harassing phone call would
indeed be playing a dangerous game.

Or if that fails, try

13A Tosca Drive Gorakan,

Gorokan, Phil. How many times!!!

(02) 4393 9920

and ask for Paul ( aka Edward)

Ha! Your netstalking is on the nose, Phil. No one called Paul (or
Edward) lives at 13a. And I have never been known as anything but
Paul.

Incidentally, have you moved lately, Phil? If not we all know where
you live should we need to pay you a visit, individually or
collectively.

[Arny Krueger]

"paul packer" wrote in message
...
On Thu, 14 Sep 2006 22:39:35 +1000, "Phil Allison"
wrote:


"paul packer"

What on earth is wrong with this "Phil Allison" person?


How long have you got, George?


** Long enough to telephone NSW Australia ??

Try: 13 Tosca Drive Gorakan

It's Gorokan, Phil. How many times!!!

Note that in Paul's world, anything that isn't spelled perfectly right is
dismissed out-of-hand unless it was posted by one of his cronies.

[paul packer]

Arny Krueger wrote:
"paul packer" wrote in message
...
On Thu, 14 Sep 2006 22:39:35 +1000, "Phil Allison"
wrote:


"paul packer"

What on earth is wrong with this "Phil Allison" person?


How long have you got, George?


** Long enough to telephone NSW Australia ??

Try: 13 Tosca Drive Gorakan

It's Gorokan, Phil. How many times!!!

Note that in Paul's world, anything that isn't spelled perfectly right is
dismissed out-of-hand unless it was posted by one of his cronies.

Tautology! "perfectly", "right".

[Ian Iveson]

Paul Packer wrote:

Tautology! "perfectly", "right".

In this context, yes, but don't get carried away with the idea.

cheers, Ian

[Phil]

Joseph Meditz wrote:
Phil wrote:

Joseph Meditz wrote:


Phil Allison wrote:


"Andre Jute"


Let's hear some more about this dynamic phase shift that pours a pint
of vinegar into a Crown preamp.


** Dynamic phase shifting of audio signals is all around us, all the time.
The fact that cones move, continuously alters the origin and hence time of
arrival of any higher frequencies being simultaneously radiated. Phase
shift in degrees ( at any point in time) is simply 360 x cone excursion /
wavelength of the high frequency.

Some call this effect " Doppler Distortion" - a misnomer.



Hi Phil,

Here's my take on this interesting topic.

I say that this is precisely an acoustical frequency modulator. If you
input two sinusoids, one low and one high, then the spectrum of the
upper one will be spread out about its center. And the greater the
amplitude of the bass signal, the greater the modulation index. From
the modulation index one could predict what the side bands will look
like.

I found the term "Doppler Distortion" helpful. The situation here is
not exactly like the sound of the horn of a train passing a station.
Rather, it is the sound of the horn of a crazy train oscillating back
and forth across the station.

Joe


So, is an acoustical frequency modulator some type of equipment? It does
sound like what I *think* Otala is saying happens when a feedback amp
gets hold of two sinusoids, as you say. What is a good methos for seeing
this spread? Someone suggested (oh hell, I think it was Arny; a USEFUL
idea???) using a spectrum analyzer, maybe it's that simple?

By the way, I *think* PA is wrong, in a way. It may be that a cone
moving forward at a bass frequency can Doppler shift a high frequency
signal, but doesn't the mic that recorded the two frequncies to begin
with invert this process, thereby cancelling it out? Just thinking ...

Phil


Hi Phil,

I tried to respond to your email, but it bounced back twice.

Anyway, it looks as though your questions have been answered.
Regarding cancellation, I think that, even if you could use the very
same loudspeaker that generates the sound as a microphone to pick up
the sound, it would still not cancel the effect of the moving cone
because the sound reaching the "microphone" will be weaker than the
transmitted signal. Hence it would not move the "microphone" cone as
much, and its resulting rate of change of phase will be less than that
of the transmitting speaker.

Joe

Sorry about that, I keep forgetting to add that you have to remove my
head to email me off-list.

Yes, I think you and Phil Allison are right on this one. I could have
sworn that the speaker books say that the high frequency components do
not have a "phase-smear" caused by the low frequency excursions of the
cone, due to "something" (I thought because the *ratio* of movements in
the mic cancelled out the *ratio* in the speaker). Even before I looked
in the books, however, thinking about what Phil said, it became obvious
that he is right, there is definitely a time-smearing of the high
frequency signals due to the low frequency movements of the cone. I then
thought "Wow, the books are wrong!" but I can't anything in the books on
it, so that obviously is my bad, alone. Okay, I hate to say it, but
Phil, you were RIGHT, and I was WRONG, period. So, is this one reason
why *good* horn systems sound so much more lifelike, and especially have
more *impact*, because the much smaller excursions result in less
time-smearing of the HF signals?

Phil

[Phil Allison]

"Phil"

Yes, I think you and Phil Allison are right on this one. I could have
sworn that the speaker books say that the high frequency components do not
have a "phase-smear" caused by the low frequency excursions of the cone,
due to "something" (I thought because the *ratio* of movements in the mic
cancelled out the *ratio* in the speaker). Even before I looked in the
books, however, thinking about what Phil said, it became obvious that he
is right, there is definitely a time-smearing of the high frequency
signals due to the low frequency movements of the cone. I then thought
"Wow, the books are wrong!" but I can't anything in the books on it, so
that obviously is my bad, alone. Okay, I hate to say it, but Phil, you
were RIGHT, and I was WRONG, period. So, is this one reason why *good*
horn systems sound so much more lifelike, and especially have more
*impact*, because the much smaller excursions result in less time-smearing
of the HF signals?


** Not at all.

Nearly all hi-fi speakers are 2 or 3 way designs, which eliminates the
issue.

Horrible full range driver designs like the Bose 901 suffer from very
obvious IM distortion when played at highish volume.

In known examples of full ranger drivers, IM products exceed the induced
phase shift products in amplitude by an order of magnitude, at least.

Dynamic phase shift ( aka Doppler distortion) does exist, but is practically
immeasurable & inaudible since it is buried under a much worse distortion.

Nothing to do with amplifiers, whatsoever.




........ Phil

[Phil]

Car wrote:
paul packer wrote:

On Sat, 9 Sep 2006 15:02:13 +1000, "Phil Allison"
wrote:

"Phil"

You know, I have terminal cancer, and maybe heart problems (waiting
for the results),


** Don't be so modest with your medical boasting -

you also have terminal autism and bi-polar disorder.



but I would rather be me, and dead soon,


** Then we all have something to look forward to.





....... Phil



You have a heart as big as all outdoors, Phil.



Go to: http://www.cancer-coverup.com/fighte...um-science.htm

You may find some hope for your situation, it is your choice.

Good luck.

Damned interesting! It might be a case of correlation, rather than
causation, meaning that the true cause of low cancer rates could be due
to another factor that is also present, but I think it's worth checking
out. One thing you figure out if you have some disease long enough is
that the medical community has some, but not all, of the important facts
concerning both the true nature of various problems, and the best
solutions. In other words, I have learned the HARD WAY to (1) listen to
everything my doctors tell me, and (2) take their words with a grain of
salt, and research the problem/proposed solution myself. It pays off an
unreasonably high percentage of the time, considering the amount of
money we pay to the medical system. Mind you, I blame the system more
than the doctors, as we basically expect each doctor to do his/her own
research into every issue, instead of having many teams at a national
level, with no restraints from the FDA or lawyers, research one disease
per team, and then send the results, even if that means several
competing results, to doctors.

Thanks,
Phil

[Phil]

Chris Hornbeck wrote:
On Sat, 09 Sep 2006 11:27:49 GMT, Phil
wrote:


I would love to, but I REALLY want to read the paper he wrote, or at
least presented, referred to here, and not just his previous papers.
I've looked in JAES, and there's nothing (although I think the older
papers are there). Any ideas on how to find something like a collection
of his papers?


Email me a USPS address.

All good fortune,

Chris Hornbeck
"Man is the measure of all things. Sigh.
Happy Ears!" -Al

Chris,

I got the article; very interesting! To think that in '73 he was making
SS power amps with an OPEN loop response of 1 MHz, whoa ... It's not
that I don't think we could improve on his design today, mind you, but
he listed a lot of very interesting points and ideas that definitely
have a place even today. Now if I can just find that cursed paper on the
conversion by the feedback loop of amplitude distortions into
"phase-smearing" (as opposed to the normal phase-shifts that exist at
the low and high frequency limits of the amp). Oh well, I think I know
most of what he was saying, just not the precise amounts as a function
of bandwidth and dB of feedback.

Thanks,
Phil

[Arny Krueger]

"Phil" wrote in message
...

I got the article; very interesting! To think that in '73 he was making SS
power amps with an OPEN loop response of 1 MHz,

No great shakes. It's just a matter of keeping the open loop gain down.
Local feedback works.