Reply
 
Thread Tools Display Modes
  #1   Report Post  
Posted to rec.audio.tubes
Ian Bell[_2_] Ian Bell[_2_] is offline
external usenet poster
 
Posts: 861
Default Menno van der Veen Masterclass

Don't know if anyone is interested but I got this little snippet in the
email form Elektor today:



http://tinyurl.com/82upa5


He seems to have discovered yet another type of distortion which he has
christened Dynamic Damping Factor Distortion (DDFD).

Cheers

Ian
  #2   Report Post  
Posted to rec.audio.tubes
Patrick Turner Patrick Turner is offline
external usenet poster
 
Posts: 3,964
Default Menno van der Veen Masterclass



Ian Bell wrote:

Don't know if anyone is interested but I got this little snippet in the
email form Elektor today:

http://tinyurl.com/82upa5

He seems to have discovered yet another type of distortion which he has
christened Dynamic Damping Factor Distortion (DDFD).


Well, the DF does change during a wave cycle. Ra isn't constant at all
points; if it was, there'd be less THD and IMD.

Patrick Turner.

Cheers

Ian

  #3   Report Post  
Posted to rec.audio.tubes
Arny Krueger Arny Krueger is offline
external usenet poster
 
Posts: 17,262
Default Menno van der Veen Masterclass

"Ian Bell" wrote in message

Don't know if anyone is interested but I got this little
snippet in the email form Elektor today:



http://tinyurl.com/82upa5


Nice touch, promising an article and slamming us with an advertisement. :-(


  #4   Report Post  
Posted to rec.audio.tubes
John Byrns John Byrns is offline
external usenet poster
 
Posts: 1,441
Default Menno van der Veen Masterclass

In article ,
Patrick Turner wrote:

Ian Bell wrote:

Don't know if anyone is interested but I got this little snippet in the
email form Elektor today:

http://tinyurl.com/82upa5

He seems to have discovered yet another type of distortion which he has
christened Dynamic Damping Factor Distortion (DDFD).


Well, the DF does change during a wave cycle. Ra isn't constant at all
points; if it was, there'd be less THD and IMD.


It sounds to me like you are saying this isn't really a new discovery, but has
always been part of the known THD and IMD.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/
  #5   Report Post  
Posted to rec.audio.tubes
Arny Krueger Arny Krueger is offline
external usenet poster
 
Posts: 17,262
Default Menno van der Veen Masterclass

"Patrick Turner" wrote in message

Ian Bell wrote:

Don't know if anyone is interested but I got this little
snippet in the email form Elektor today:

http://tinyurl.com/82upa5

He seems to have discovered yet another type of
distortion which he has christened Dynamic Damping
Factor Distortion (DDFD).


Well, the DF does change during a wave cycle. Ra isn't
constant at all points; if it was, there'd be less THD
and IMD.


DF changes during a wave cycle is of course always there if the amp is
nonlinear, and all amps are at least a tiny bit nonlinear. It is only going
to have the possibiilty of being an audible problem with amplifiers that
have quite a bit of nonlinear distortion. Whether you would hear this second
order effect among the primary effects of all that nonlinearity seems
doubtful.





  #6   Report Post  
Posted to rec.audio.tubes
Jim Gregory Jim Gregory is offline
external usenet poster
 
Posts: 25
Default Menno van der Veen Masterclass


"Patrick Turner" wrote in message
...


Ian Bell wrote:

Don't know if anyone is interested but I got this little snippet in the
email form Elektor today:

http://tinyurl.com/82upa5

He seems to have discovered yet another type of distortion which he has
christened Dynamic Damping Factor Distortion (DDFD).

Well, the DF does change during a wave cycle. Ra isn't constant at all
points; if it was, there'd be less THD and IMD.

Patrick Turner.

Cheers

Ian


.... christened? --- named, surely!!

Does this mean, thanx to a new parameter surfaced by Menno van der Veen,
MSc., leading[??] designer of valve amplifiers and output transformers,
yet -another- type of DFM has to be designed and marketed? It will cost a
bomb!
Bad enough to fork out £160 + return train fare for Brum.
Jim


  #7   Report Post  
Posted to rec.audio.tubes
Ian Iveson Ian Iveson is offline
external usenet poster
 
Posts: 960
Default Menno van der Veen Masterclass

Ian wrote:

He seems to have discovered yet another type of distortion
which he has christened Dynamic Damping Factor Distortion
(DDFD).


Menno is fond of copyright, e.g. "super triode". It doesn't
mean that the named entity is new, but rather that his
particular analysis is new, in form or in detail.

How about "perveance distortion"? (copyright Ian Iveson,
just now). This is the distortion arising from variations in
valve perveance according to signal level. Of course it's
part of the total distortion we all know about, but I am the
first to isolate it and give it a name.

As for DDFD, surely that must be something in the frequency
domain? Otherwise it's a stupid name. DF is not the same as
output impedance. Neither is it a property of an amplifier
or a speaker. Rather it arises from the relationship between
the two.

From memory, the closest he gets in the book cited in your
link is a plot of the frequency response of an amp +
loudspeaker, in terms of SPL probably, with several
different examples of amp output impedance. Predictably, the
output impedance is pretty much related to the amplitude of
the variations in SPL with frequency.

Extending analysis in that direction, dynamic changes in
output impedance, and hence in DF, will lead to dynamic
variation in the amplitude of SPL variations with frequency.
Can that be called distortion? What about the consequent
IMD, arising from both the speaker and the output stage?
That would not be part of the usual measured IMD of an amp
with a sine wave and constant load, I suppose.

Er, in case that paragraph doesn't make sense: a plot of SPL
v frequency is wriggly, and if the output impedance of the
amp is greater, then the wriggles are greater but more or
less in the same places. If the output impedance varies
dynamically, then so do the amplitudes of the wriggles.
Different wriggle amplitudes will result in different levels
of IMD.

AFAIK, once you subtract all the forms of distortion which
already have names from a typical amp output, then there
isn't much distortion left worth naming. OTOH, standard
measurements are designed to isolate the forms of distortion
that already have names.

Menno is sensitive to the sales of Plitron transformers. My
guess is that he has divided up total distortion in a way
that serves the purpose of isolating a particular aspect
that can be shown to depend on transformer quality. I
consider it certain that, in that lecture, he will go on to
demonstrate that DDFD is minimised by the use of Plitron
output iron.

The book, BTW, is worth a read if you can sort the wheat
from the chaff and reorganise it in your head.

My advice is to minimise the OPT turns ratio.

Ian


  #8   Report Post  
Posted to rec.audio.tubes
Nick Gorham Nick Gorham is offline
external usenet poster
 
Posts: 134
Default Menno van der Veen Masterclass

Ian Iveson wrote:


Extending analysis in that direction, dynamic changes in
output impedance, and hence in DF, will lead to dynamic
variation in the amplitude of SPL variations with frequency.
Can that be called distortion? What about the consequent
IMD, arising from both the speaker and the output stage?
That would not be part of the usual measured IMD of an amp
with a sine wave and constant load, I suppose.


A lot of work was done in the 1950s with regard to DF and output
impedance, there seems to have been a period where amps were produced
with variable DF, ie +ve, zero and -ve output impedances. Maybe you
should read some of the papers from that period, they were far from
groping in the dark.

--
Nick
  #9   Report Post  
Posted to rec.audio.tubes
Ian Iveson Ian Iveson is offline
external usenet poster
 
Posts: 960
Default Menno van der Veen Masterclass

Actually there is more...

If the output impedance, and hence the DF, varies
dynamically with signal amplitude, then that part of the
output due to the transient response of the speakers will be
distorted. I think, but there are too many layers of
nonlinearity for me to envisage. If I'd ever had a
motorcycle with multi-rate damping, rather than multi-rate
springs, I might have got a feel for DDFD. If it leads to
distortion in the time domain, then it should feel like some
higher-frequency vibration when riding over bumps.

There is a 3D graph that probably has a name, and shows SPL
on the vertical axis, frequency on the horizontal, and time
out from the page. If you give the speaker a kick, then you
get a number of ridges at various frequencies, each of which
dies away along the time axis. Greater damping will make the
ridges shorter. Varying the damping dynamically according to
SPL will, I guess, result in the appearance of extra or
greater ridges at harmonic frequencies.

Perhaps we should all chip in and sponsor you to attend
Menno's event?

Alternatively, maybe someone would dare to ask about DDFD on
rec.audio.tech? They're really clever, but our delegate
might get savaged.

Ian


  #10   Report Post  
Posted to rec.audio.tubes
Ian Iveson Ian Iveson is offline
external usenet poster
 
Posts: 960
Default Menno van der Veen Masterclass

Nick Gorham wrote

Extending analysis in that direction, dynamic changes in
output impedance, and hence in DF, will lead to dynamic
variation in the amplitude of SPL variations with
frequency. Can that be called distortion? What about the
consequent IMD, arising from both the speaker and the
output stage? That would not be part of the usual
measured IMD of an amp with a sine wave and constant
load, I suppose.


A lot of work was done in the 1950s with regard to DF and
output impedance, there seems to have been a period where
amps were produced with variable DF, ie +ve, zero and -ve
output impedances. Maybe you should read some of the
papers from that period, they were far from groping in the
dark.


Actually they were pretty much groping, mostly, from my
memory.

Perhaps you could help Ian with a summary of what you
learned?

However, as I realised after I posted, *dynamic* variation
in damping factor, i.e. during the wave cycle, adds another
and quite different can of worms.

Ian




  #11   Report Post  
Posted to rec.audio.tubes
Andre Jute[_2_] Andre Jute[_2_] is offline
external usenet poster
 
Posts: 631
Default Menno van der Veen Masterclass

On Jan 2, 3:26*pm, "Arny Krueger" wrote:
"Patrick Turner" wrote in message



Ian Bell wrote:


Don't know if anyone is interested but I got this little
snippet in the email form Elektor today:


http://tinyurl.com/82upa5


He seems to have discovered yet another type of
distortion which he has christened Dynamic Damping
Factor Distortion (DDFD).

Well, the DF does change during a wave cycle. Ra isn't
constant at all points; if it was, there'd be less THD
and IMD.


DF changes during a wave cycle is of course always there if the amp is
nonlinear, and all amps are at least a tiny bit nonlinear. It is only going
to have the possibiilty of being an audible problem with amplifiers that
have quite a bit of nonlinear distortion. Whether you would hear this second
order effect *among the primary effects of all that nonlinearity seems
doubtful.


We've spent nearly two decades telling you, dear Arny, that there are
subliminal effects that cannot (yet) be measured but that nonetheless
cause listeners to become uneasy, to prefer on setup to another for
reasons which they cannot quite articulate. All that the above tells
us is that you don't listen too well.

Andre Jute
Tear drop vase, tear drop vase, plum distressed -- Cash Register,
Heaton's, Bandon, Co Cork, Eire, Christmas 2008
  #12   Report Post  
Posted to rec.audio.tubes
Peter Wieck Peter Wieck is offline
external usenet poster
 
Posts: 2,418
Default Menno van der Veen Masterclass

On Jan 2, 4:41*pm, Andre Jute wrote:

A lot of self-serving crap.


And

Arny may be a odious jackass, but he is far less dangerous than you
are. He represents that segment of the population that has found a
kernel of some aspect of the smallest part of a greater "truth" and is
riding that kernel for all it is worth. Happily, he doesn't fool too
many for too long as he is not terribly clever.

You, on the other hand are nothing but a liar, poseur and charlatan
with no claims on any sort of truth. Sadly, you are far more clever
than Arny and so you do appeal to those 'some of the people' that one
can fool 'all of the time'.

That the two of you so richly deserve each other is a happy accident,
but as one might suggest to any two of your sort making out in public
before it gets too hot-and-heavy: Get a room!

Peter Wieck
Melrose Park, PA
  #13   Report Post  
Posted to rec.audio.tubes
Peter Wieck Peter Wieck is offline
external usenet poster
 
Posts: 2,418
Default Menno van der Veen Masterclass

On Jan 2, 2:42*am, Ian Bell wrote:

He seems to have discovered yet another type of distortion which he has
christened Dynamic Damping Factor Distortion (DDFD).


Which he carefully does not define - at least in the teaser. Which
leaves what is meant by it open to rampant speculation. Which as
Patrick leapt on immediately will *very most likely* (to be
distinguished from "almost certainly") turn out to be a subset of
already clearly understood and defined sorts of distortion(s) together
with a means to 'solve' it and further the means to perhaps profit
from it. The analogy that comes to my mind is old wine in new skins.

I admit to getting very squirrelly when expected to swallow whole (at
a significant cost) any sort of NEW discovery with reference to tube
equipment. Not to state that it is impossible - Clarke's Laws suggest
otherwise - but that it is quite unlikely.

So, who is going to go? A bit far for me, and with that same £160 (not
to mention air-fare, food & lodging), I could purchase quite a bit of
tube equipment for experimentation and enjoyment in these troubled
times.

Peter Wieck
Melrose Park, PA
  #14   Report Post  
Posted to rec.audio.tubes
Arny Krueger Arny Krueger is offline
external usenet poster
 
Posts: 17,262
Default Menno van der Veen Masterclass

"Andre Jute" wrote in message


We've spent nearly two decades telling you, dear Arny,
that there are subliminal effects that cannot (yet) be
measured but that nonetheless cause listeners to become
uneasy, to prefer on setup to another for reasons which
they cannot quite articulate. All that the above tells us
is that you don't listen too well.


Andre I'll bet that you don't know that the above is completely irrelevant
to what I said.


  #15   Report Post  
Posted to rec.audio.tubes
Ian Bell[_2_] Ian Bell[_2_] is offline
external usenet poster
 
Posts: 861
Default Menno van der Veen Masterclass

Peter Wieck wrote:
On Jan 2, 2:42 am, Ian Bell wrote:

He seems to have discovered yet another type of distortion which he has
christened Dynamic Damping Factor Distortion (DDFD).


Which he carefully does not define - at least in the teaser. Which
leaves what is meant by it open to rampant speculation. Which as
Patrick leapt on immediately will *very most likely* (to be
distinguished from "almost certainly") turn out to be a subset of
already clearly understood and defined sorts of distortion(s) together
with a means to 'solve' it and further the means to perhaps profit
from it. The analogy that comes to my mind is old wine in new skins.

I admit to getting very squirrelly when expected to swallow whole (at
a significant cost) any sort of NEW discovery with reference to tube
equipment. Not to state that it is impossible - Clarke's Laws suggest
otherwise - but that it is quite unlikely.

So, who is going to go? A bit far for me, and with that same £160 (not
to mention air-fare, food & lodging),


Now, Peter, you know it would be my privilege to provide food and
lodging for you here in the UK. ;-) By the way, all the 6SN7s worked fine.

Cheers

ian


I could purchase quite a bit of
tube equipment for experimentation and enjoyment in these troubled
times.

Peter Wieck
Melrose Park, PA

Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Menno van der Veen publiceert zijn nieuwe boek op internet postmaster Vacuum Tubes 1 February 5th 04 07:01 PM
Super-Triode of V.d.Veen anybody? Andy Evans Vacuum Tubes 2 December 4th 03 02:37 AM


All times are GMT +1. The time now is 06:25 PM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"