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Old 28th June 2008, 02:23 AM   #1
lineup is offline lineup  Sweden
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Thumbs up Matti Otala - An Amplifier Milestone. Dead or Alive

hi

Lineup here.

We sometimes, quite often actually! mention
the name, papers & amplifier works of Matti Otala.

There are a few, very few, audio profiles that can become
a legend in their own lifetime.
We are fortunate to have some of those at this forum .......
Become a legend when you are dead and bueried, is much less difficult.

Anyway, this man Dr. Matti Otala from my neighbour
country of Suomi ( I live in Ruotsi http://fi.wikipedia.org/wiki/Ruotsi )
is actually still alive and working & thinking
He has passed his 60th birthday, going for 70 now.
But this is not always a major drawback.
In fact, it is a nice thing to be able to get old & still be in good shape

Me, Lineup, like to honor Matti, while he still may ba able to read my lines.
Here is a picture of this friendly looking man.
And some further links to his current whereabouts in internet.

Click the image to open in full size.

Quote:
The birth of the Otala amplifier

On an AES conference in 1973, Dr. Matti Otala presented a paper describing the design of a TIM-free audio amplifier. Present at this conference was Svein Erik BÝrja, a Norwegian record and broadcasting producer, and a great audio enthusiast. Svein Erik BÝrja also was one of this times greatest Golden Ears. He was able to hear even the slightest imperfection in an audio component. Having been dissatisfied with the sound of that days transistorised audio amplifiers, he here saw an opportunity for getting an audio amplifier of a new generation. The talk of Dr. Otala about TIM also was an explanation to Svein Erik for the imperfections he himself had noted in audio amplifiers.

He brought the paper to a friend of him who was running his own audio company in Norway, Per Abrahamsen of Electrocompaniet. Per decided to make a try at the amplifier ........
HighTechForum Finland: http://www.hightechforum.fi/index.cfm?j=365834
Otala Family: http://www.otala.com/
Matti Otala, 60yrs, reception 28-Dec-1999: http://www.otala.com/webcast4.html


Regards, Lineup
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Old 28th June 2008, 03:17 AM   #2
AKSA is offline AKSA  Australia
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Lineup,

I agree with your assessment. Matti Otala was very significant in the development of audio amps, as has been Pass, Wurcer, Widlar, Bailey, JLH, and Peter Walker.

Reading through his CV it is evident that Telecommunications has been more his line in recent decades, Nokia must be very pleased with him!

I thought Matti died of cancer in Canada last year, but it clearly states he is a Professor at a Finnish University?

Could be wrong, John Curl and Nelson would know......

Cheers,

Hugh
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Old 28th June 2008, 04:20 AM   #3
lineup is offline lineup  Sweden
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Quote:
Originally posted by AKSA
Lineup,

I agree with your assessment. Matti Otala was very significant in the development of audio amps, as has been Pass, Wurcer, Widlar, Bailey, JLH, and Peter Walker.

Reading through his CV it is evident that Telecommunications has been more his line in recent decades, Nokia must be very pleased with him!

I thought Matti died of cancer in Canada last year, but it clearly states he is a Professor at a Finnish University?

Could be wrong, John Curl and Nelson would know......

Cheers, Hugh
Cancer?
My father died in prostate cancer in March 2000
This I know very well. Because I cried out loud and my tears were many, many at his funeral.

About the person Matti Otala I do not know too much.
Except, that anyone thinking he is a good audio designer,
have to mention him in papers & references.

Otala represent a paradigm shift in amplifier making.
The past transistor happiness about the new possibility of having 'unlimited gain' + huge negative feedback
was not all justified.
To be a bit moderate in gain, allows for a good open loop bandwidth
and so using moderate level of global feedback reduces some types of distortions.
Like TIM. Which is said our human ears are very sensitive to.

I will have to make some better research to find out if he is among us living, still.

Dead or alive .. he is forever a part of Audio Amplification History.
For sure


Lineup
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Old 28th June 2008, 04:35 AM   #4
lineup is offline lineup  Sweden
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Quote:
Originally posted by lineup

About the person Matti Otala I do not know too much.
Except, that anyone thinking he is a good audio designer,
have to mention him in papers & references.

Otala represent a paradigm shift in amplifier making.

Lineup

Here is an example of such references to Matti Otala.
This time in a classical audio paper by Jean Hiraga.
Translated from french to english by a www.diyaudio.com member!

Lineup


Quote:
The Many Faces of Distortion
A look at the various types of distortion and the results of an interesting experiment involving counter-Electro-Magnetic force (EMF).

By Jean Hiraga
Translated by Jan Didden
Glass Audio, May 2005, Pages 40-49

POWER INTERFACE IIM

We all know Matti Otala, a Finnish researcher who discovered the origin of an obscure type of distortion, Interface Intermodulation Distortion (IIM). This new form of distortion, found as a result of a new measurement method, is caused by the amplifier design: the bandwidth of each stage, group propagation time, delay introduced by the various stages with impact on the feedback loop action during transients. Among the different measurement schemes proposed to prove the existence of this type of distortion, there is no lack of interest in those that simulate the appreciable energy caused by the counter-electromotive force of the loudspeaker and the acoustic enclosure, which is re-injected -- not as a voltage but as an energy -- into the output of the amplifier -- while the amplifier itself is reproducing a different frequency.

Actually, the classical measurements (harmonic distortion, intermodulation distortion according to the SMPTE norms) do not allow detecting it. The basics of this method, which was proposed about 20 years ago by a team of researchers from the University of Musashi, Tokyo, are still relevant today. They are depicted, with some extensions, in Fig. 2.

The method consists of injecting a 1kHz signal at the input of the amplifier under test to obtain a nominal 15W power into the load at the output. This is either a pure resistive 8-ohm load or a loudspeaker. A low output impedance power generator, in turn, through a non-inductive 250-ohm / 1000W resistor and a LC filter to suppress the 1kHz band (self-induction of 7.5mH/15A plus capacitor 3.3uF), inserts a 50Hz signal into the terminals of the load or the loudspeaker. You thus recover the composite signal present at the load or loudspeaker terminals. This signal is then fed into an audio spectrum analyzer.

As shown in the figure, the composite signal is returned to the amplifier and its input, because .....
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Old 29th June 2008, 02:15 AM   #5
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Quote:
Originally posted by lineup



Here is an example of such references to Matti Otala.
This time in a classical audio paper by Jean Hiraga.
Translated from french to english by a www.diyaudio.com member!

Lineup



Matti Otala made valuable contributions to the audio industry, even if some of us do not agree with all of his conclusions and assertions. At minmum, he made us think harder and put the spotlight on some important issues in amplifier design.

He was actually very much an objectivist and a measurer in many ways. With most of the distortions he described, he proposed means of measuring them that were valuable. This was the case with IIM as well. The spotlight he put on IIM largely led to more focus on the need for high-current amplifiers. His conclusions about IIM and negative feedback were not quite right, however.

More can be learned about IIM on my website at www.cordellaudio.com in the published papers section.

Matti tended to wrongly blame these readily measurable distortions (using his proposed techniques) on the use of negative feedback.

Cheers,
Bob
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Old 29th June 2008, 02:24 AM   #6
lineup is offline lineup  Sweden
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Quote:
Originally posted by Bob Cordell

Matti Otala made valuable contributions to the audio industry, even if some of us do not agree with all of his conclusions and assertions. At minmum, he made us think harder and put the spotlight on some important issues in amplifier design.
------------

More can be learned about IIM on my website at www.cordellaudio.com in the published papers section.

Matti tended to wrongly blame these readily measurable distortions (using his proposed techniques) on the use of negative feedback.
Cheers, Bob
Yes, that is the way I have got it from some projects.
Accessive negative feedback is 'the crook' of these distortions.
And Otala was one of the first to go deeper into this issue.

Thanks for shining some light on audio history by your perspective, Cordell.
You are your self a small part of common audio electronics heritage


> More can be learned about IIM on my website at
> www.cordellaudio.com in the published papers section.


I think I have missed your paper about IIM.
What is actual Title of that publication of yours, Bob?

Regars, Lineup
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Old 20th May 2009, 06:46 PM   #7
lineup is offline lineup  Sweden
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Happy birthday, Mister Otala of Finland.
You look friendly.
Sure would like to meet you.

/lineup
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Old 20th May 2009, 08:20 PM   #8
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Quote:
Originally posted by lineup

Happy birthday, Mister Otala of Finland.
You look friendly.
Sure would like to meet you.

/lineup

Happy Birthday, Matti!

Thanks for the heads-up lineup.

I had the pleasure of meeting Matti several times at AES conventions long ago, and he is indeed a friendly guy who is also a gentleman.

Cheers,
Bob
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Old 20th May 2009, 09:13 PM   #9
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Happy Birthday, Matti!

I built your amp in the 70ís; itís still a good amp.

Cheers
Stinius
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Old 20th May 2009, 09:42 PM   #10
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I have one in my office, it is still a good amp.
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