John Curl's Blowtorch preamplifier part II - Page 2953 - diyAudio
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Old 19th November 2012, 01:23 PM   #29521
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Quote:
Originally Posted by fas42 View Post
I can instantly "ruin" the quality of sound from my system by adjusting how any of the cables are precisely set up within their environment, although nothing in the normal electrical sense has altered one iota. But, what will have been altered is how the materials of the cable and their environment interact.
Incorrect (assuming you are speaking about IC's or PC's)

Any modification of the ground loop path will modify the system. Flux loop trapping is the culprit here, not any material properties of the cables.

As to the micro-diode discussion which I won't quote anyone specific...

A wire inductance is comprised of two parts..the internal inductance which at DC is 15 nH per foot, and the external proximity based inductance, which is typically 160 to 180 nH per foot.

If the interstrand resistance is high, there will be a direct impact on internal inductance up to a total of 30 nh per foot (2 wires). The more oxide, the higher the internal inductance because the orthogonal conductivity is broken.

Also, the more interstrand resistance, the closer to symmetry the internal currents of the wire will be, so external inductance will not change as much vs frequency.

If you suspect a poor oxidised multistrand cable, run a few amperes through it at 20 Khz, and look for high order harmonic hash.

If anybody suspects a cable as doing any bad things as a result of oxide, just test the darn thing. Do an Ls/Rs sweep from 20 hz to half a Mhz..get yourself a 4284A..

Oh, almost forgot...the speaker end zobel? It is good, and a simple consequence of applying t-line theory to a speaker cable.

jn
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Old 19th November 2012, 01:37 PM   #29522
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Ground loops (even those that are capacitively coupled), ground currents, shield currents, RFI, EMI, field induced noises - that's all the magic of the cables, and I agree, cables do make a difference.
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Old 19th November 2012, 01:40 PM   #29523
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Richard Marsh and Walt Jung wrote an article on contacts, as I recall, in about 1980, in TAA or was it AUDIO?
We all went into learning mode as to how to make better connections, both permanent and temporary.
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 use it on my bench, and have done so for the last 30 years (give or take a couple of years).

Last edited by john curl; 19th November 2012 at 01:58 PM.
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Old 19th November 2012, 01:53 PM   #29524
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Originally, there was Cramolin Red, the active cleaner. Then there was also Cramolin Blue, a preservative, for the most part. Today, we use DeoxIT from Caig labs, a less effective but useful cleaner.
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Old 19th November 2012, 02:18 PM   #29525
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EMC
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Old 19th November 2012, 02:58 PM   #29526
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Lightbulb Blowtorch schematic

Second hit in Google pictures:
http://www.amplimos.it/images/BLOWTORCH%20preamp.png


Last edited by QSerraTico_Tico; 19th November 2012 at 03:09 PM.
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Old 19th November 2012, 03:02 PM   #29527
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Very close schematic. Thanks, QSerra...
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Old 19th November 2012, 03:50 PM   #29528
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Wow, that's my simulation!
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Old 19th November 2012, 03:51 PM   #29529
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Good work, PMA.
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Old 19th November 2012, 03:51 PM   #29530
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Quote:
Originally Posted by kgrlee View Post
Thanks for this George. Good to see people have been busy while I've been in the bush Rythmik seemed to have picked up my point about temp. affecting DC resistance but I think David Birt's solution is more elegant.

I'll get my lawyers to see Yamaha et al for infringing my Powered Integrated Super Sub patents.

The Dynamic Duo are Stan Lipsh*tz & John Vanderkooy, the High Priests of ABX and other good stuff. But their ABX team also have at least one of the best ears in the business.
Positive feedback by current had been used way before. Even Heathkit had tube amp with such thingy implemented, for sale. How it could be patented after that?
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