John Curl's Blowtorch preamplifier part II

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Good try, the posse here is against you.
These?
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Depending on the resolution of your system (including speakers).... there can be a noticable change in sound character at first turn-on to final burn-in/cycling period. Eventually, the sound stablizes and doesnt change anymore except the first few seconds/minutes after turn on. A good amount of it had to do, IMO, to electrolytic caps not being fully formed or annealed at the factory.

This is a very reasonable observation, in case if electrolytics are permitted to play in the signal paths. But even if there are no essential role of electrolytics (some schematics exclude it), film caps (those with metallized films more than with melal foils) also demonstrate notable sound adjustment (improvement) due to burn-in, and similar examples could be continued.
Also would like to add, that audio is a mix of technical and "audiophile" things, nobody could convince a person to buy that among equally measuring amps there MKT melallized caps are used, instead of the amp with copper-foil film caps, supposed the prices are equal.
 
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Also would like to add, that audio is a mix of technical and "audiophile" things, nobody could convince a person to buy that among equally measuring amps there MKT melallized caps are used, instead of the amp with copper-foil film caps, supposed the prices are equal.

I understand this statement means nothing for traditional engineering and persons working at it, but those who wins prizes for sound of their amps do find sence in this statement.
 
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I assume an amplifier burnt in to failure would not sound better. When processes were less robust burn-in for offset and Ib were required, but they got worse or better.

Agreed - but at least it would not fail 1 hour into its service life at the customer!

I progressed and now work at a company that makes >70 billion packaged semiconductor devices a year and we **** ourselves if we can't keep total failures below 50 parts per billion.
 
Your point? :D

se

I'm writing a technical article, and was trying to decide which to put first, I'm not sure of the target audience demographics.

Well, did everyone who can appreciate applied research find the article useful to show how the paradigm of the 'stability' of pure copper or any other metal is an illusion? That is why break-in is possible and often very useful.

No. I am involved in applied research, and your incorrect interpretation of what was written is abysmally incorrect and not applicable. It does however, make good fodder for salesmen who target uneducated consumers.

More likely incorrect interpretation and assessment, and attribution of irrelevant information
Bingo.

I understand this statement means nothing for traditional engineering and persons working at it, but those who wins prizes for sound of their amps do find sence in this statement.
I was going to respond, but decided your 15 minutes is up.

jn
 
Don't worry Vlad, they do this all the time.

Yes, better take everything easy and be happy. If to take seriously, one could follow a fate of Gregory Perelman, he was offended by those who long time refused to recognize his proofs in mathematics, and deciced to get out

"Dr Grigori Perelman, is refusing to accept the prestigious $1 million "Millennium" mathematics prize awarded by the Clay Mathematics Institute in Cambridge, MA."
 
Extrapolation

Curious how data generated for thin films is extrapolated to bulk applications...

Good point: While these grain boundaries certainly exist, any effect due to them would only be observed when the entirety of the current flow had to cross them (<10uM). This means the makers of those nasty 8-legged bug lookin things (apologies to SW) may have to deal with them. Well, maybe not even then, as a replication engineer I had the opportunity to have my nickel and aluminum vapor deposited and sputtered films etched and SEM'ed, and as it turns out plasma and vapor deposition are notable for lack of grain, so maybe not...

At any rate these grain boundaries would be massively paralleled (short circuited) in any as-cast conductor larger than a few thousands of an inch.

In addition, in any drawn wire (even OHNO Continuous Cast is drawn) these coherent structures are worked out of existence by drawing. Indeed this is one of the attributes to drawn high-tensile steel wire: drawing creates an amorphous structure that is remarkably homogenous and reliable...for which I am glad every time I cross a suspension bridge.

Were we talking about bridges, copper wires, conductors on PCBs or inside ICs? I get lost in this thread sometimes...

Howie

Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
 
Phase-plug loaded ES diaphragm

Nice impulse response and square w transfer. I like it. I also have 'something' interesting.
... ( US3590169 )

In principle it is extremely similar to the Beverage ES systems. (Patent US3668335 - Electrostatic loudspeaker - Google Patents) Constant path-length loading of a flat diaphragm to a horn throat. I have to say the Beverage IIs, within their SPL limitations imaged as good or better than any speaker I have ever heard. I have always been a Quad fan, but one of their several limitations is an extremely small sweet spot where the imaging is correct. Thanks to the line-radiator configuration the Beverages had an image that you could walk through, and seemed to have a huge sweet spot...entirely separate from the speakers in the space between them. Wayyyyyyy out of my budget at the time, and still are.

Howie

Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
 
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