John Curl's Blowtorch preamplifier part II

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Pieter, you have to give more info to make sense of what you truly make. I went to your website and I got some pretty pictures, little more.
However, you do use different transformer laminations for different audio transformers. Why don't you JUST use 12 mil lams? Can't you explain to people here what happens if you do? Thanks in advance.

Because he makes TOROID core transformers, John, NOT laminated core transformers.

*sigh*

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Pieter, you have to give more info to make sense of what you truly make. I went to your website and I got some pretty pictures, little more.
However, you do use different transformer laminations for different audio transformers. Why don't you JUST use 12 mil lams? Can't you explain to people here what happens if you do? Thanks in advance.

Yes, I (try to) select the best core material for a given application.
In practice this means nanocrystalline amorphous or cobalt amorphous material for small signals (up to line level), and "standard" amorphous or high quality grain oriented silicon steel material for line opt's up to output transformers.
 
Let us talk laminations, Pieter. That is the hot topic here at the moment. Then we can go to nanocrystalline amorphous and its advantages. The BIG problem I have with amorphous is LOW FREQUENCY distortion. However, that can wait. First, eddy current losses due to lamination thickness, etc. Please remember, it was you who introduced yourself with 1 mil lams. just this morning.
 
Pieter, please, I am serious. I live in THE PEOPLE'S REPUBLIC OF BERKELEY' so your political affiliation is of little consequence, BUT I need INFO!

John, apart from my MC step-up transformers and inductive volume control, all transformers are custom made to order for DIY'ers; there is no catalogue.
By the way, I was in the SF bay area last summer but I did not feel like being in a socialist environment ;)
 
One of the unfortunate things that has become even more difficult, is the dissemination of intellectual information. On one hand, if someone wants a 'Wiki' view of something, it is easily available. However, for a deeper or a historical view, it can be expensive, unless one has access to an extensive technical library.

True.

For most here, I would presume that it would not make that much difference, as most here do not design audio equipment professionally, in any case.

But still lots of people here would like to expand their knowledge beyond what's easily available on the net and on mass-market books.
And being no professionals, some of the prices charged by the AES are not justified by their scope.
 
Unfortunately, Pooge, it doesn't say much about the transformers, themselves, just how they can help to improve S/N in limited quality input stages.

No actually a transformer can be designed to improve the SNR of any JFET input stage. Do I have to post the .06nV article (Simple K170 diff-pair input) again? Or for that matter the Jensen app note., 1.23dB noise figure from 10 Ohms considerably better than a BT.
 
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'POWER TO THE PEOPLE!' We hide our socialist tendencies in an exterior of normalcy. Just ask anyone in Texas about Berkeley or the SF Bay Area, or even the Swiss!
Once in Switzerland, I visited a hardware store to buy some tools. I introduced my associate and myself as from San Francisco. I got a note of disapproval from mentioning that. '-)
 
Yes, Scott, presuming the transformer is IDEAL! However, there are differences between transformers, and I seek to find these differences. Then I can chose between them.
It is POINTLESS for me to put in a less than optimum transformer. I am willing to go as high as 200 Euros / transformer, in limited quantity, 100 or so. Pieter, can you work in this range?
 
Let us talk laminations, Pieter. That is the hot topic here at the moment. Then we can go to nanocrystalline amorphous and its advantages. The BIG problem I have with amorphous is LOW FREQUENCY distortion. However, that can wait. First, eddy current losses due to lamination thickness, etc. Please remember, it was you who introduced yourself with 1 mil lams. just this morning.

First of all I am curious what causes your problem with amorphous and low frequency distortion. Low frequency distortion points in the direction of core saturation. Standard amorphous cores which I use for line outputs, interstage and output transformers have a lower saturation treshold (1.56T) than for instance HiB (it's already in the name) silicon steel cores (over 2T). However with a well calculated amorphous core transformer low frequency reproduction should be no problem.
 
Yes, Scott, presuming the transformer is IDEAL! However, there are differences between transformers, and I seek to find these differences. Then I can chose between them.
It is POINTLESS for me to put in a less than optimum transformer. I am willing to go as high as 200 Euros / transformer, in limited quantity, 100 or so. Pieter, can you work in this range?

John,
I just pop into this huge thread, and you can't blame me for not reading all in order to see what is going on.
What is the application of your transformer?
 
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