DIY Module Front panels (two questions and a big tangent)

I learned electronics in the vacuum tube days. Truly. And a lot of electronics I had was US military surplus and everything was built like a tank. So, yep, I remember those days and components.

I’ve got a capacitor in the garage that weighs a couple of hundred pounds from my days of exploding wires and melting coins via inductive pulses. Of course I’m afraid of the old stuff I have as it is probably filled with PCB.

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Oh, I have one that is not as big as the one you mentioned, but quite chunky anyways

16uF 500v. You can kill a person with this thing. And you don’t even have to use electricity…

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Just looked and mine is 100uF at 600VDC.

Little did you know how “big tangent” your post had :wink: :rofl:

Well, like always. I enjoy tangents though. It makes discussions more interesting and lively

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These are just two different packaging options. “back in the day” you could get them in cans or in epoxy - The ones I used looked exactly like that (on the right). Although I tended to use 2N3904/2n3906. That old synth of mine is full of them. I ran an unregulated ±15 V on the backplane, then each module had a discrete +/- `10v regulator in the module.

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Plastic is just cheaper than metal or ceramic. Technology always evolves towards the cheaper for bigger profits.

yeah, I’m just making the point that plastic was super common “back in the day”. Maybe we saw more ceramic IC packages than we do now…

Yeah, I’m just referring to my observations from working 21 years in the semiconductor manufacturing industry. Most everything would start in ceramic or metal packaging but evolve to cheaper plastic.

Of course it has now been 25 years since I retired from the semiconductor industry. That’s several “Moore’s Law” cycles :wink:

well, all the chips and small signal transistors I used in the 70’s were in plastic. Well, at work I got some super expensive burr-brown op-amps that came in a metal can, but that’s about it.

The transistors on the picture are 2N2222 - not 2N222

“sources” say the plastic casing was common from around 1965.

(2N222 is an old USSR germanium transistor - it looks more like the transistors on the second photo.) Not so 100% sure about this - trying to find a good source

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Also, at least in the past many devices were available to military specifications which quite often were metal or ceramic packaging. Consumer devices were more likely to be plastic or become plastic.

This is typical of the circuit boards in my homemade synth. This is a dual VCO card. You can see the old “Q81” tempo resistors on top of the SSM VCO chips. Everything is in plastic except for the 3080’s.

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Just one last thing on this. Metal and ceramic packaging was usually “hermetically sealed” whereas plastic was not although a lot of improvement happened over the years for plastic packaging. Plastic was usually good enough for consumer uses.

I hope you stocked up, those tempco’s are £3.45 each now (USD 4.22)

haha - these photos are from just a few years ago, but I’m pretty sure I haven’t applied power to this thing since maybe 1997. I would be afraid that at least the power supply caps would explode. I have to say it looks pretty nice in there, though. I’ll bet the tempo resistors at still in good shape.

And one more… power devices were usually in metal cans for thermal conductivity and heat sinking.

Yes, but there also all those IC power regulators in TO-220 packaging, which was plastic, but with a metal tab on it.

But for high power it was always can.

can

Power supply in the Voyetra 8 had a pair of 2N3055 power transistors on a big heatsink.

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My bad! Both of them are indeed 2n2222. And 2n222 exists, yeah, it is germanium pnp, but I am not sure if it is exclusively USSR thing. The marking seems european\american. Soviet marking is a bit different, it usually starts with KT (for kremnijevyj [silicon] tranzistor [transistor]), there are also GT (for germanium), but I think they started to mark germanium transistors as KT. I might be wrong…

Anyway! Sorry for this mistake

Could it also be the temperature thing? Metal is much more heat-conductive…