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Re: my latest power supply

>

>>>> >>>>>> >>>> >>>>> >>>>> >>>>>>>>>>>> >>>>>>> >>>>>>>"John Larkin" wrote in >>>>>>>message >>>>>>>news: snipped-for-privacy@4ax.com... >>>>>>>> >>>>>>>> >>>>>>>>>with 2 HTs one tube and one from solid state. >>>>>>>>> >>>>>>>>>has a 400va power transformer, 2x200ma chokes >>>>>>>>>2x5U4GC tubes. >>>>>>>>> >>>>>>>>>its only part of my new hifi system >>>>>>>>>im still yet to build the 2 power amps >>>>>>>>>in a same look. >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>>> Cute. What's it like underneath? >>>>>>>> >>>>>>>> John >>>>>>>> >>>>>>> >>>>>>>havent finished wiring it yet. >>>>>>> >>>>>> >>>>>>I'm a fan of stretched bus wire. Get a piece of shiny tinned bus wire >>>>>>or enameled magnet wire. Chuck one end in a vise and grab the other >>>>>>end with vise grips and pull until it yields a little. It becomes >>>>>>absolutely, beautifully straight. Cut it into chunks and wire away. >>>>>> >>>>>>It wrecks the conductivity of course, but beauty must suffer. >>>>>> >>>>>>John >>>>>> >>>>> One does not need to perform the pull trick to achieve the >>>>> straightness. Retaining the lattice integrity is pretty important. >>>>> Won't see me doing it. >>>> >>>>ok ilike earth buses and point to point. >>>> >>> >>> >>> Yes, but compromising an electrical property in the name of appearances >>>ain't real bright. Like I mentioned, there are several ways to get a >>>straight run, as if that even matters. >> >>Well, name a few. >> >>The conductivity isn't harmed much by pulling the wire. It does look >>great. >> >>John > > > Harm is harm, Mr. Quantify as desired, but never when it goes against >something you stated. What an ass.

It's only harm if the resistance goes up enough to cause problems.

> Worried about conduction? Use silver bus. Still, there are much less >destructive ways of getting it true and straight without putting stress >on the wire or work hardening it.

Please tell us a couple.

I just measured the resistance of 22" of #18 bus wire, sorta ragged looking as pulled off the spool. Then I stretched it hard enough to make it beautiful and straight.

You're an expert on this sort of thing, so estimate the resistance before it was stretched, and how much it changed.

John

Reply to
John Larkin
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Barring any work hardening/crystallization, 5% of stretch gives you

10.25% of resistance increase.

So you can not likely measure any change due to weak-kneed hand stretching :-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
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| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
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      The only thing bipartisan in this country is hypocrisy
Reply to
Jim Thompson

I question the efficacy of both sets of measurements.

You, saying that "you measured" something doesn't give one any warm, fuzzy feelings upon contemplating the declared "observed results".

Reply to
Archimedes' Lever

Why didn't you just say "I don't know how to do that"?

John

Reply to
John Larkin

JL > Why didn't you just say "I don't know how to do that"?

A > =A0 No, John, you [f ing] idiot. =A0My statement A > was that YOU do not know what you are doing.

Archie! BACK IN YOUR KENNEL!

Reply to
Greegor

Fuck off, Egreegious error boy.

Reply to
Archimedes' Lever

I wonder if anyone ever explained to dimbulb that copper wire is made by drawing it through dies to reduce the diameter?

--
Lead free solder is Belgium's version of 'Hold my beer and watch this!'
Reply to
Michael A. Terrell

That work-hardens it, which makes it stiff and increases resistance. It's usually annealed afterwards for electrical applications. If it's not annealed, it's called "hard-drawn" copper, and the resistivity is about 4% more than annealed. The breaking tension of the hard stuff is about 50% higher than for the annealed.

We anneal our manganin shunts to get the TCs and drift under control, after all the work-hardening of rolling out the metal and forming the shapes.

I'm sure Dimmie can add details. He knows all about this stuff.

John

Reply to
John Larkin

Wow! I've never seen a pot that black, AlwaysWrong.

Reply to
krw

The immature little boys just ain't real bright, folks. Recess is over now, go back inside so you can interrupt the teacher by making your arm pits fart.

For the stupid among you, that essentially is saying "Grow the f*ck up."

Reply to
Archimedes' Lever

I made rings out of Copper wire, back in the sixties, as a kid. Oooops!

Reply to
Archimedes' Lever

One can drag a length of wire across the edge of a bench or drag the shaft of a screwdriver along the length.

Having said that there are times when having a taught wire is bad. Consider thermal expansion of the chassis. Granted that's less of a problem with solid state and home electronics, but with tubes or a system exposed to environmental extremes the system can be damaged.

Dan, U.S. Air Force, retired

Reply to
Dan

An educated wire is worse than that most dangerous of creatures, a clever sheep

;-)

-- "Electricity is of two kinds, positive and negative. The difference is, I presume, that one comes a little more expensive, but is more durable; the other is a cheaper thing, but the moths get into it." (Stephen Leacock)

Reply to
Fred Abse

It *is* annealed every so often during the process, Mike.

I did the controls on a vacuum annealing plant doing that job.

--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
                                             (Stephen Leacock)
Reply to
Fred Abse

I realize this, but simply stretching the wire as John suggested is not going to put it under the same stress as being pulled through die after die to reduce the diameter.

--
Lead free solder is Belgium's version of 'Hold my beer and watch this!'
Reply to
Michael A. Terrell

I had the feeling someone would catch the misspelling as soon as I sent it. May all your fleas have camels. :)

Dan, U.S. Air Force, retired

Reply to
Dan

It most certainly will. I will say it again, for all of you complete idiots. Copper WORK HARDENS. That means that ANY flexure that occurs with anything more than ultra-slow speed causes crystallization of the lattice at the flex point, and re-flexure causes micro-structure cracks at said points.

So, Johhny boy's straightening method is lame, AND it DOES work harden the copper at ALL stretch locations, which will NEVER be even throughout the length of the wire.

Reply to
Archimedes' Lever

Try it. The wire becomes absolutely smooth and straight throughout its length. The work hardening probably has less effect on the resistance than the elongation; but the per-unit-length resistivity only increases a couple of per cent anyhow.

It sure does look good.

John

Reply to
John Larkin

Elongation IS where the work hardening occurs. D'oh!

Copper... if you move it, it will harden.

Unless you move it *very* slowly.

Reply to
Archimedes' Lever

The change of resistance from elongation is purely geometrical; the wire gets longer and its cross-sectional area/diameter correspondingly drops, and the area reduction increases its per-unit-length resistance. There will be additional resistance increase from messing with the crystal structure. Two things are going on here. You could anneal out the crystal thing but not the elongation.

How slowly would I have to stretch it to avoid work hardening?

John

Reply to
John Larkin

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