gold plated binding post lugs without the audiophoolery

I like the placement at component TR8 ! ...snip

No, we used AC also as part of the measurement, but needed the DC resistance as well, as a baseline from which AC losses could be calculated.

Yes it could have been done by alternating the DC, but this was 1970s, and such things were not easy then. As it was, the bridge cost about the same as a couple of cars.

On Tue, 21 Jan 2014 09:35:12 +0000, John Devereux Gave us:

The sandman must have visited them the night before they packaged the boards.

You need a dentist's micro buffer head for their little air driven drill motors, and a very good touch sensitive coordinate checking machine to hack and make transit to each location so the buffer head can clear the spot. ;-) Hehehe

Ah, hell... just sand the whole thing with 600 grit for a few seconds per zone. wash and bake before use.

OSP except the P was "prevantative" :)

might work if the paper's flexible enough else grit blast

Or just email that photo to the supplier and they apologize profusely and send a shiny new batch FOC - which is what happened :)

But, the binding posts are likely some kind of copper alloy (bronze? brass?) Why not, instead, use thermocouple connectors with known-alloy pins? Copper is standardized for type T, and T connectors in male/female pairs aren't expensive

On Thu, 23 Jan 2014 11:03:27 +0000, John Devereux Gave us:

Of course!

However... to make use of those boards, one would make lab/devel boards from them, etc.

Depends on the node count, and various sub-circuit purpose(s).

But does provide proto data which is closer to what a new model 'spin' operates like. Far better than a bench proto, because most of the traces and device placements are already there.

Then again, one must weigh the costs of prepping a PITA like those.

I think it is funny these days. We used to breadboard a design, and the PCB layout was not really too far off, dimensionally speaking.

These days, with 0204 and the like, any bread board layout will be miles off the real world layout trace timings.

So is everything these days all simulated completely, including parasitic elements?

I feel old.

For voltage standards, bridges, null detectors and so forth they tend to be "Tellurium Copper", usually gold plated. Something like 99.5% copper I think.

An interesting idea for home-brew equipment, but I have to deal with what is provided on the kit too. And that is tellurium copper binding posts.

Like these:

"DecadentLinuxUser" found the exact things I am looking for, but $100 shipping for me unfortunately. :(

Pure copper is just horrible to machine, gummy, grabby and it work hardens.

A touch of Te and it becomes much easier to machine (with some compromise to the properties, not so bad at room tmeperature). That's probably the reason for the alloying.

I was playing with a Cu-Te rod (~2" in diameter) on the lathe last year, and you can really get a nice finish etc. without herculean efforts.

I don't think I'd want to deliberately introduce constantan-copper junctions where they were not required.

Best regards, Spehro Pefhany

Yes I think that is right, the Te does not have magical thermocouple-less properties, how could it, it is to improve the machining. Does it reduce oxidising at all?

Isn't one pole just copper? I assumed whit3rd meant to just use one pole of each connector.

It doesn't seem to. The chunk I have looks pretty much like corroded copper (I'm not sure they're oxides, might be suphides or something).

Cute, eh?

Ah, that would make more sense, thanks!

CuTe indeed. If you could just machine me up a dozen lugs or so that would be great :)

I know you're joking, but even with manual machining I could probably do it, but it would take a bunch of hours. It would be a lot easier from strip. Solid-barrel Tellurium Copper lugs machined from billet.

Do you think audiophiles would pay enough to make it worthwhile?

Nah, has to be OFC. Or silver. But sometimes they don't like silver, for some reason.

I don't doubt you could make money off it though. Don't forget to use words like billet. ;-)

Tim

They would sell a kidney and a lung, if the hype is good enough.

They do already I think, that is why I found nothing but speaker connectors when I searched. :(

I see there is a company "Tellurium" making a fine line of cost-effective quality products. So good luck mentioning the name of that metallic element in an audio context.

"Mains cable of the year 2012"

British engineering expertise at its best.

Yay.