Thank you for the info and the warning, the 60 odd pieces I have all come from Singapore and all adhere to the basic 2SK170 specs, I tested them. I plan to use them as Borbely-type input buffers and input differential devices, I'll need quite a few of them.
Copper tarnishes, aluminum can be anodized and a great finish is practical. What would a thin copper layer actually do, except for high RF perhaps? Perhaps, gold plating over copper would be better than aluminum. Might be difficult to make it thick enough through hogging out a solid billet.
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Gold plating copper or silver will be a visual disaster. Copper, silver (and many other) diffuse rather quickly through gold, giving that tarnished look, unless a barrier layer is first used. Common is nickel, but that's magnetic.
So milled from a solid block of gold seem to be the only viable option. Adds a nice number, likely 6 figure, to the price tag, so sales won't be a problem for the target customer population.
Heavy gold plating should work OK. Not gold 'flashing'. We started gold plating our Vendetta Research circuit boards about 30 years ago, and the original ones still look OK, However some of our later gold plated circuit boards, where the price of gold went up so high that they skimped on the gold thickness, does tarnish somewhat. This would not be good, so a relatively THICK gold plating would be necessary for a world class audio product, perhaps $50,000-$100,000 dollar model.
Constellation already pays BIG BUCKS for their aluminum based cases, far more than the CTC Blowtorch ever did, as Demian already knows, having worked alongside me on the design of some of their products, (sorry about 'outing' you Demian). In fact, the CTC Blowtorch is almost a bargain, compared to the Constellation products. My concern is shielding performance, coupled with 'doing no harm' to the audio signal, and have something look OK, not 'metal sculpture'.
Constellation already pays BIG BUCKS for their aluminum based cases, far more than the CTC Blowtorch ever did, as Demian already knows, having worked alongside me on the design of some of their products, (sorry about 'outing' you Demian). In fact, the CTC Blowtorch is almost a bargain, compared to the Constellation products. My concern is shielding performance, coupled with 'doing no harm' to the audio signal, and have something look OK, not 'metal sculpture'.
Silver tarnishes but otherwise works well over copper. And the tarnish is conductive. Heavy gold (250 microinch or more) over copper works OK. Light gold (25 microinch like China gold watches) is a disaster unless the green splotches are part of the design. You could use platinum as a barrier coating.
Sony used to tout copper-plated chassis in a lot of their top-shelf ES stuff. Dunno if it was effective at anything besides marketing.
It was highly effective at looking good 🙂 all screws used to mounting internal stuff where also copper (plated?)
Normally, it is for RF shielding, best RF conductivity. However, it is not the case in audio, where are the shielding practices and principles are always violated. The same for CTC BT, it has a milled box with plenty of wires getting inside untreated, so all the HF interference is inside again, coming along the audio wires.
As do quite a few othwrs as well, such as Marantz. Denon, etc.. on their top tier products of course.
Waly, Waly, Waly,
You don't mill gold you cast it and then mill to final dimension if needed.
Actually a practical idea. Great place to store some of my gold, in plain sight!
An antique shop I used to pass regularly had in the window a "brass" clock from the estate of Andrew Carnegie. I made them an offer on it they did not accept. Some one else noticed it did not tarnish and instantly bought it at their asking price. He resold it at Sotheby's as a solid gold clock.
I gave a nephew in law some 5 C (K) ruby cuff links. He still doesn't believe they are real. (Told him to check with any jeweler, but he thinks I am putting him on.)
So cast a bit of gold into the case is actually a great place to store it with low risk! Even saves on the current off site storage fees.
You don't mill gold you cast it and then mill to final dimension if needed.
Actually a practical idea. Great place to store some of my gold, in plain sight!
An antique shop I used to pass regularly had in the window a "brass" clock from the estate of Andrew Carnegie. I made them an offer on it they did not accept. Some one else noticed it did not tarnish and instantly bought it at their asking price. He resold it at Sotheby's as a solid gold clock.
I gave a nephew in law some 5 C (K) ruby cuff links. He still doesn't believe they are real. (Told him to check with any jeweler, but he thinks I am putting him on.)
So cast a bit of gold into the case is actually a great place to store it with low risk! Even saves on the current off site storage fees.
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Hi John
Rods stock may be in a pre heat-treatment state.
Read the certifications. Composition and heat treatment status is certainly documented. Don’t hesitate to ask.
http://www.asminternational.org/documents/10192/1917073/htp00103p047.pdf/d384e0ac-bce6-437e-b049-b1ba4c8e563c
http://www.nssmc.com/en/tech/report/nssmc/pdf/106-05.pdf
Correct. Rudder and elevator balance counterweights (3-15mCi each). They were replaced by tungsten counterweights. (S.B. dated prior to 1985)
Almost. Ionising radiation is of very low concern as long as D.U. remains outside of the body.
Inhaled dust is a real danger both due to high biological effect (RBE) of A radiation as well as D.U. high chemical toxicity.
https://www.atsdr.cdc.gov/toxprofiles/tp150.pdf
Don’t machine it, don’t sand it. Protect it from corrosion. (D.U. when corroded becomes powdery).
Aluminium primer is a recommended corrosion protection film for D.U. items.
George
Thanks for the links. I am quite surprised by the extreme range of properties the various alloys have. I'll be studying these quite a bit, mainly out of intellectual curiosity. (that sounds better than just "curiosity" doesn't it?? Makes me look all "intellectual-like".😛
Great...I visited a customer I made a special supercon magnet for, they needed help connecting it up. They used DU as the shield/cradle of the magnet, and were grinding it to fit. Now it seems like the 100 feet away from the work wasn't far enough..sigh... 15 years ago... wonder how long it would take..
John
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