John Curl's Blowtorch preamplifier part II

Status
Not open for further replies.
Disabled Account
Joined 2012
E/M field theory has to be relearned for those that do high speed digital layout, and though seperate in many ways again high speed digital uses various analogue functions such as s-parameters for simulation.
Analogue is not totaly dead, but you do find that real analogue engineers are becoming fewer when you go to different establishments and they tend to be older, though where I am now has numerous analogue enginers(and acoustic ones) so its nice to know there are still some. Agree though digital is seen as the main stay of electronics, though with digital you do have to have a large software team in the background... Maybe its the sexier option at Uni these days, whereas analogue is seen as old fashioned.

Robert Greene told me that understanding mathematics is lost on his students today because computers will do the calculations for you and thus no one derives anything anymore. Maybe same with semiconductors -- dont need to understand the physics of devices... with sim software and all.

But even in pcb layout with high speed digital... you need to know some things from analog.... like the higher harmonics travel on the outer edge of the trace and affect impedances for waveform fidelity etal. yet, even that has been characrterized in software.

Its a Plug-n-Play world (?)
 
Just like general relativity, statistical mechanics seems to attract mathematicians who suffer from 'physics-envy'. They write papers which only their immediate peers can understand. I remember attending a postgrad course (in my physics department) which claimed to be about statistical mechanics but seemed to be mainly about the properties of fibre bundles.

Regarding plug'n'play, an EE prof once told me that most of his postgrad students, when 'designing' a microwave antenna with an EM simulator, do not know what to do to the design in order to change some property so randomly change things until the plot looks about right. He had noticed that I, originally educated nearly 40 years ago and also a radio amateur, knew roughly what to do to alter resonance frequency or feed impedance.
 
Last edited:
Richard, we discrete designers do NOT need to know all the physics of semiconductors. We just use what is already made. There are general rules about semiconductor behavior, and that is really all we need. We can HIRE consultants to give us the theory, IF we need it, but it more or less just gets in the way.
 
Now, about my experience with the Otala power amplifier.
In 1975, the institute I worked at was closing down, and our lab closed with it. I went to work for someone else in Switzerland, so I stayed in the area, and there was an AES conference in Zurich the next year.
Because they had heard of me, somehow, two young guys from Norway visited me with an amp prototype that they wanted me to addition. At the time I had tried a number of the 'better' commercial transistor amps and none sounded good with my STAX Electrostatic headphones. They all sounded kind of 'phony' and gave me listening fatigue, WHEN I used the headphones. Through the Magnepans they were sort of OK.
Then these young guys let me try the Otala amp which they had copied from the AES preprint, and let me listen to it. It was a revelation! It sounded really good with my electrostatic headphones too! It wasn't very powerful, but it sounded 'right' at normal listening levels. I just had to have this amp.
They did NOT want to sell it to me, because this was their prototype, and they had to take it back across the border, where they registered it, apparently.
Well, I was very convincing, and I offered them real money AND a Quatre amp chassis that they could use for prototyping, and get them across the border. This amp was built in a very amateur way. It is amazing that it stayed working at all, BUT it did sound good, AND with a few substitutions along the way, I kept it until the firestorm in 1991 took it, my JC-80, my WATT-Puppies, and STAX electrostatic headphones, etc.
Yes, this little Electrocompaniet sounded better than just about anything that I could afford, for more than 15 years, and it was even good enough to drive a set of WATT's with remarkable sound quality.
Now what did Jan and Matti do RIGHT, to make me so enthusiastic? I knew of Otala, but I don't think I ever met the guy, before buying the amp. I had tried some of his concepts both in the GD equipment, the Levinson JC-2, and in the Institute power amp with some success, but really this little amp kicked TAIL, sonically, and I will never be sorry for the purchase. About 20 years ago, I found another Otala amp, virtually the same as the one I lost, and I have it in my office system driving a pair of Sequerra speakers. Pound for pound, this little amp beats my HCA-1000 Parasound amp, which is rather embarrassing, but it is important to be honest about such things. (end of tale)
John, Is this the amp?
 
Just like general relativity, statistical mechanics seems to attract mathematicians who suffer from 'physics-envy'. They write papers which only their immediate peers can understand. I remember attending a postgrad course (in my physics department) which claimed to be about statistical mechanics but seemed to be mainly about the properties of fibre bundles.

Like we had a course called "Theoretical foundations of electronics design". I could not understand what was there about design, because actually if was Theory of Graphs. :)

The course was mondatory, it looked more like that math professor had good connections in education high ranks to get his position.
 
An academic I know told me that the rot set in when they inflicted MBA's upon them, and they decided that the worth of an academic was the number of words they published per annum.
What then happened was that people started to adopt what he called the ."salami" method of publishing.

In this you slice what you would have normally published in a year into suitable pieces, you then put each piece on a large bun, and surround it with all manner of salads and dressings etc.
This impresses the MBA no end and they utter all sorts of things to do with reaching bench marks and win win scenarios, go away chanting their mantra and leave you alone.

The trouble is that now everybody spends a lot of time digging through and discarding all the padding to get to the salami, and of course you can't let the MBA's know what you are doing so it must be very plausible seeming obscure stuff and impossible to decipher unless you know the field intimately, apparently some of it is quite hilarious.
rcw
 
A few years ago I was looking for potential employers in the university sector. I noticed that the head of department in one institution seemed to publish at lots of conferences, but rarely in proper journals (where rejection rates are typically much higher than conferences). I looked at a few of his papers and found that each one contained about 80% of the previous one. I concluded that his actual publishing rate was about 20% of his apparent rate, and the quality was not great. I decided that this was not the sort of boss I wanted to serve.
 
A few years ago I was looking for potential employers in the university sector. I noticed that the head of department in one institution seemed to publish at lots of conferences, but rarely in proper journals (where rejection rates are typically much higher than conferences). I looked at a few of his papers and found that each one contained about 80% of the previous one. I concluded that his actual publishing rate was about 20% of his apparent rate, and the quality was not great. I decided that this was not the sort of boss I wanted to serve.

Why? You would have 80% less work to do for him. :D
 
Status
Not open for further replies.