John Curl's Blowtorch preamplifier part II - Page 2955 - diyAudio
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Old 19th November 2012, 07:01 PM   #29541
PMA is offline PMA  Europe
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I already built (and sold) some amplifiers

Pavel Macura audiopage
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Old 19th November 2012, 07:10 PM   #29542
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NP, I hope YOU would appreciate this one

Project 83 - MOSFET Power Follower
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Old 19th November 2012, 07:23 PM   #29543
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Quote:
Originally Posted by SY View Post
I have. It seemed fine.

The schematic isn't that mysterious and can be pieced together from knowing the topologies that John generally uses,
What is intellectually interesting to me is why THAT topology and not the many others available then and since? That's where the learning for me is of interest. Not blindly copying it and/or a sim of it for DIY build. Its in that distillation of many issues into a compact circuit that best meets the goals. Knowing the right goals has to be known to get the design distilled.

Also the pcb has advanced ground routing/guide paths and the like which is not blindly done, either. That is nearly a lot art. -RNM

Last edited by RNMarsh; 19th November 2012 at 07:28 PM.
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Old 19th November 2012, 07:25 PM   #29544
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Your power amp? Direct competition, locally
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Old 19th November 2012, 07:27 PM   #29545
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Quote:
Originally Posted by Nelson Pass View Post
Does your simulation show it?
Does mosfets models follow exactly gate capacitors behaviors ? (real question)
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Old 19th November 2012, 07:29 PM   #29546
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Never seen a model that would reliably reveal parasitic HF/UHF oscillations.
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Old 19th November 2012, 07:32 PM   #29547
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Originally Posted by Esperado View Post
Does mosfets models follow exactly gate capacitors behaviors ? (real question)
THEY like to be superior and disdainful. Same manner is sometimes needed to reply.
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Old 19th November 2012, 07:40 PM   #29548
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Originally Posted by RNMarsh View Post
Its in that distillation of many issues into a compact circuit that best meets the goals.
The question remains if it is the right track to follow, in order to participate at any progress ? I mean, pairing and choosing parts to minimize their defects (sometimes in a very empirical and time consuming way) at a given historical moment...
Or find way, working on topologies, to compensate them with more industrial/ low priced parts for same kind of result (listening pleasure and credible make believe).
When i first saw the price of the Blowtorch, i immediately calculated the number of records i can buy with it.
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Old 19th November 2012, 07:54 PM   #29549
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Never seen a model that would reliably reveal parasitic HF/UHF oscillations.
Can-we imagine, in a near future, that simulators can use random statistical values for components, use the board's layouts to simulate parasitic inductances and capacitances ?
I was VERY surprized when Scott said they where only use simulators at AD.
And because i'm very new to simulators, i have a big problem to evaluate how much i can rely on them.
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Old 19th November 2012, 08:03 PM   #29550
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Originally Posted by john curl View Post
Around this time, I recall Apple Computer making a BIG MISTAKE in their product. They made the Apple II computer with a number of gold plated plug-in slots, so that accessories, including extra memory could be added.
Unfortunately they FORGOT to gold plate the plug in board connections, so you had a gold-tin interface. In a relatively short period of time, the connections failed, but the board function could be recovered by just cleaning them and putting them back. Cramolin was first brought out to address problems like this. Later, it was pressed into audio service.
I think it's been around since before WWII first known as Gramolin.
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