John Curl's Blowtorch preamplifier

[KBK]

Originally posted by scott wurcer


Well said, I once had some very interesting actual network analyser results from some sensitivity to RFI tests on I to V stages at a show and Small (of Theil/Small) told me I was deluding myself (5532 and R/C is all anyone needs).

You mean those 'lumped parameter' guys? I have no comment.

[MikeBettinger]

Originally posted by dave_gerecke
Making an enclosure that allows for external connections, while also being gas tight is not an impossible task. It requires much more planning than a conventional enclosure, but it is certainly do-able. I work for a company that makes semiconductor equipment. We have vacuum chambers that process wafers using combinations of pressure, heat and high voltage. We routinely pass power signals into the vacuum chamber without any problems.

Peace,

Dave

Hi Dave,

I work for a company that probably uses your equipment. I'm also familiar with the applications. I just figure that building an enclosure that will hold a nitrogen purge with readily available connectors and mountings would be an interesting challenge.

What type of equipment does your company build? I'm a sensor applications engineer and work in etch, films, cmp, wets... (diffusion, the backend, the list goes on.)

Regards, Mike.

[john curl]

This is inappropriate. All you need is STILL AIR. It is good enough.

[MikeBettinger]

Originally posted by john curl
This is inappropriate. All you need is STILL AIR. It is good enough.

I didn't say it was necessary, It was just a thought experiment. A play on the concept of building a "pipe bomb" preamp and how it might be approached. Just check out the price of a vacuum feedthrough and it becomes apparent

I agree on the still air approach.

Mike.

[scott wurcer]

Originally posted by john curl
This is inappropriate. All you need is STILL AIR. It is good enough.

Of course you have examined the possibility before condemning it? We have several sensitive test systems that require a constant dry nitrogen purge. Is operating a sensitive preamp circuit in a neutral atmosphere more far fetched than cryo treating resistors that are already ppm accurate? Let's be open minded and consistent.

[john curl]

Go for it Scott. However, most parts are designed for dry, clean air. That should be adequate. However a relay is a different sort of component and needs an even better environment. Perhaps you should brush up on your engineering, before trying to set me up.

[scott wurcer]

Originally posted by john curl
Go for it Scott. However, most parts are designed for dry, clean air. That should be adequate. However a relay is a different sort of component and needs an even better environment. Perhaps you should brush up on your engineering, before trying to set me up.

That's not fair, I would never try to set you up. Running a preamp in an argon atmosphere might remove that last 'veil' in the way of the music is a possibility as much as many things I've seen mentioned.

The air in most places is anything but clean and dry BTW.

[john curl]

It might, why don't you try it?

[fizzard]

Originally posted by john curl
Fizzard, quenching is NOT cryoing. Cryoing is a SLOW process, with vastly different results. You don't even know the definition. The difference has been noted by others in the past.
For example, you just can't dip a component into liquid nitrogen and get the same result as a closely controlled cool down and warm up.
We are not treating fish here, which would have the opposite effect . Did you know that, Fizzard. Do you know about flash freezing and WHY it is done? What could be the difference between just cooling something slowly and doing it quickly?

Yes I am well aware of the difference. Do YOU know why heat treating of metals sometimes involves rapid and sometimes slow cooling? Or sometimes a constant temperature heat soak in molten salt? Or progressive heating? Do you know what case hardening or precipitation hardening are without googling? Do you know why these things aren't done at cryogenic temperatures? Here's a hint: Because it doesn't work. Maybe mercury of gallium might undergo heat treating at sub zero temperatures, but not copper or steal.

Originally posted by KBK
I suspect if his metals issue was brought back to a specific minimal wear and loading consideration, then the cryoing would show positive effect.

It's either harder or it's not.

Originally posted by hermanv
I also do not know if cryo treatment has any effect on magnetic properties of conductors. I do know that this domain hysteresis is small and doesn't show up with traditional cable measurement tools (Ohms, group delay, capacitance, inductance)

But alas it can be heard! (Just not in any credible test.) There's a $1 million prize out there somewhere, I'm sure it could be extended to cover the same cable in both cryo and non-cryo form.

Originally posted by MikeBettinger


An excellent solid copper enclosure using 4" X 9" 40mil thick copper sheets that can be purchased in hobby stores (Small Parts inc also sells sheet copper). I use a dremel and their 409 cutting blade to cut the various panel pieces without distorting the edges and then sweat solder the joints using plumbing solder and a propane torch. With a bit of planning you can drill the holes for connectors and pcb mounting hardware in advance. If it wasn't for the need to connect to the outside world you could fill it full of nitrogen...

I recently built a MC amp enclosure that turned out quite nice. I'll post a picture this evening if I remember.

Mike.

I made a vase in elementry school by shaping really thin copper foil, and then electro-plating copper onto it. You can get the copper sulfate in a pet store (used for aquarium fungicide). It took a while to get around 5mm thick, it was ages ago so I don't remember exactly how long it took. If I ever make my own pre-amp I think I'll do something similar.

[scott wurcer]

But alas it can be heard! (Just not in any credible test.) There's a $1 million prize out there somewhere, I'm sure it could be extended to cover the same cable in both cryo and non-cryo form.

The cable guy backed down, I hear. I figure there will never EVER be a test on neutral ground of any of these claims. I predict that BOTH sides will never agree to a test of these issues where there is a real possiblity that either will be proven wrong.