John Curl's Blowtorch preamplifier part II - Page 751 - diyAudio
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Old 17th December 2010, 09:46 PM   #7501
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John,

I watch this thread for enjoyment and laughs. Why do you guys have so much fun talking about stuff 30+ years old? Certainly an op amp with a 30 volt swing and a gain bandwidth product of 10 MHz will work fine at audio frequencies.

Also, why would anyone in their right mind pay $20,000 to $40,000 for an amplifier? Lots of snake oil.

Rick
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Old 17th December 2010, 09:57 PM   #7502
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Well, I wouldn't pay $20,000-$40,000 for a world class preamp, but people do, all around the world. I just design them. AND there is no 'fat' in this design, just quality, and versatility.
Everyone, who can think outside their specific values and considerations, must understand that there is a market out there for Bugatti's and Bentleys. I can't afford them, but some people can, and I wish them well. SOMEONE had to design them, and how much fun, as an engineer, it must have been, to do so.
Sawreyrw, just get a preamp based on the design we just made, and live a happy life. It should cost you around $100, if it is done right.
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Old 17th December 2010, 10:09 PM   #7503
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Quote:
Originally Posted by sawreyrw View Post
John,

I watch this thread for enjoyment and laughs. Why do you guys have so much fun talking about stuff 30+ years old? Certainly an op amp with a 30 volt swing and a gain bandwidth product of 10 MHz will work fine at audio frequencies.

Also, why would anyone in their right mind pay $20,000 to $40,000 for an amplifier? Lots of snake oil.

Rick
Since John is under heavy moderation, my answer probably hits you first.

John is a very respected audio electronics designer who happens to share some of his knowledge here. His good memory and historic accuracy is valuable to some of us here. He puts things into perspective like no one else.

So your comment about "any opamp will do" just shows your lack of knowledge. Sorry to say that. There is a lot of snake oil in this business. Please don't connect John to to that.
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Old 17th December 2010, 10:15 PM   #7504
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Thanks 2 quad, yes there is a lot of 'snake oil' in this business, but not EVERYTHING is 'snake oil' any more than Asian medicine or holistic (sp?) medicine is completely bogus. In fact, I recommended to my boss, just today, to check out Chinese Medicine for his problem, since the hospital is not working out. Why not?
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Old 17th December 2010, 10:23 PM   #7505
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I just threw out the 10 Mhz comment just to raise some feedback. But this amp would have a bandwidth of 100 KHz at a gain of 100. Isn't that way more than adequate for an audio amp? In addition, the full power bandwidth (slew rate limit) is well above the audio frequency range.

One thing I'm not sure about is how much distortion is acceptable. I doubt anyone can detect .1% or even 1%. I know it's not that simple and depends on which harmonics, etc., but still, why get obsessed with it?

I know that John is well respected, but he is also an arrogant so and so, and that's why he is under moderation. Sorry about the negative comment, but that's how I feel.

Last edited by sawreyrw; 17th December 2010 at 10:33 PM. Reason: Correct typos
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Old 17th December 2010, 10:42 PM   #7506
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This is getting a bit off topic (as usual), but you'll find some of your answers here: http://www.meridian-audio.com/ara/coding2.pdf
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Old 17th December 2010, 11:01 PM   #7507
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Quote:
Originally Posted by sawreyrw View Post
I watch this thread for enjoyment and laughs.
Good for you. Enjoyment and laughs are healthy.

Quote:
Originally Posted by sawreyrw View Post
Why do you guys have so much fun talking about stuff 30+ years old?
I, for one, find some of 30+ years old knowledge that John Curl shares quite illuminating.

Quote:
Originally Posted by sawreyrw View Post
Certainly an op amp with a 30 volt swing and a gain bandwidth product of 10 MHz will work fine at audio frequencies.
From engineering view point, yes. From audiophile view point, I haven't heard one yet.

Quote:
Originally Posted by sawreyrw View Post
Also, why would anyone in their right mind pay $20,000 to $40,000 for an amplifier? Lots of snake oil.
How do you know it's nothing but snake oil?
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Old 17th December 2010, 11:09 PM   #7508
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How do you know it's nothing but snake oil?
Very good point, Joshua
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Old 18th December 2010, 12:08 AM   #7509
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Are you laughing at me, sir? May I ask what you know about audio design that would enable you to make such a statement?
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Old 18th December 2010, 12:35 AM   #7510
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I could have drawn a lot of circuits in the meantime instead of watching another useless discussion if it makes sense what we are doing here.
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