John Curl's Blowtorch preamplifier part II - Page 3289 - diyAudio
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Old 18th January 2013, 05:21 PM   #32881
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Quote:
Originally Posted by john curl View Post
WHY would I bother with what I bother with in audio, if I was stuck with CD, only?
Soooo, what about enjoying-us with a sample of whatever source you like, and a copy of it across Blowtorch ?
You will take no risk with my low discerning ears, as i still enjoy listening so many awfull sounding CDs from my collection on my mid-fi system.
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Old 18th January 2013, 05:25 PM   #32882
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Yes Richard, that will work to remove any measurable distortion.
However, does it really sound good? That is an important question.
For example: I once designed a special 600 ohm audio driver for Sound Technology, sort of like an 811, that would give only a few thousands of percent or less at 100KHz and below at about 6V out. I did it by using a special design with 100KHz open loop bandwidth, and closing the loop at 12dB/octave. Worked just fine, FOR THE APPLICATION.
However, I would not necessarily recommend it for quality audio.
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Old 18th January 2013, 05:25 PM   #32883
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Originally Posted by RNMarsh View Post
Very cool, IMO
Thanks, however it is a little acrobatic, i would not use that in a industrial amp.
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Old 18th January 2013, 05:30 PM   #32884
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I can't Esperado, I don't have the digital equipment to make quality digital stuff. Maybe in future.
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Old 18th January 2013, 05:44 PM   #32885
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To deviate a little from the technical discussions.
I have a chance to listen to one of John Curl's products.
My present pre-amp is tube-based, Audible Illusions Modulus 3 + MC Phono. The MC Phono part is designed by JC, by the looks of it from the outside, it's constructed with discrete JFETs and MOSFETs.
All I can say is that LPs never before sounded so good on my audio setup.
Hat off to JC.
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Old 18th January 2013, 06:03 PM   #32886
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Originally Posted by john curl View Post
Now just to make this clear: The Blowtorch is rated for 3V out, balanced. It is not perfect here, but at this output, a Parasound amp following it will be clipping at over 1000W in my living room. See the problem? It is absurd then to worry about its operation, even its 7th harmonic above 3V.
Everyone knows this, it is trivial. So why you were asking the full scale for AD797 and distortion magnified 1000x??? And speaking about issues if any trace of 7th is seen then??? The reason why I am so disappointed with your reasoning is that you are misleading the readers.

You have different measures for the BT and AD797 (or another opamps).
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Old 18th January 2013, 06:11 PM   #32887
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Good for you, Joshua.
PMA, TO SEE IT, AND WHAT IT IS COMPOSED OF.
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Old 18th January 2013, 06:26 PM   #32888
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Don't you think it's just a wee bit misleading to show spectra from a 797 with distortion magnification, high output voltage, and heavy load, then compare it to something you sell/sold tested with low output voltage, light load, and no distortion magnification?

Man up and admit that your accusation about relative 7th and 9th order distortion was mistaken and not based on any actual data. It's the honest thing to do.
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Old 18th January 2013, 06:48 PM   #32889
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Originally Posted by john curl View Post
TO SEE IT, AND WHAT IT IS COMPOSED OF.
Mainly silicon, i believe
I used to look, first, at the simplified schematics of OPAs provided in all the data-sheets in the good old days. It was like a first shake hands where you get a feeling of your interlocutor.
I wonder why they have disappeared from the datas of most of the recent ICs.
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Old 18th January 2013, 07:29 PM   #32890
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Quote:
Originally Posted by Esperado View Post
Thanks, however it is a little acrobatic, i would not use that in a industrial amp.
Perhaps, but I just like the concept -- which can be applied in many other ways, I'm sure. I do recognise it is another form of feedback overall and what ever implications that might have.

-R
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