vacuum tube prototyping methods

[ajmartin]

I built this for prototyping ages ago.
View attachment 1092809
But now I use a Heathkit IP-17 for the HV power supply.

NIce!

 

[bananasplit_00]

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WTF is being shown on this thread ?!

High-voltage 300-500V prototypes assembled with 2.54mm Dupont wires, hanging wires with crocodile clips, and breadboards originally designed for low-voltage are very very very unsafe to say at least. Once you get expanding corona, you will understand how dangerous tube circuits could be. On occasion my fingers slipped and I shorted traces (with voltmeter probes) on vacuum tube amplifier PCB, expanding corona burned huge hole in the board, filling room with enormous amount of black flakes.

Many many years ago, when I'm was a schoolboy experimenting with electronics, I've twice got 220v hand-to-hand voltage shock. Sometime later had 400V shock, and the feeling was like my heart stopped. Thanks to the mother nature, my body seem to be able to tolerate this without loosing consciousness. Someone else may not be so lucky. Since then I'm vary cautious with this kind of assemblies, and strongly recommend everyone else to be so, too.

Vacuum tube builder may be like sapper, his first mistake may be his last.

If you are referring to what I posted, that is strictly because I am not doing HV.

12V quick POC is all that is for which it is perfectly fine for.

The signal integrity is garbage through a breadboard so the sound is awful anyway(+all the inductive loops, capacitive interference and other random EMI thrown out by stuff around the lab 🙂 )

I have a lot of respect for HV stuff so one hand goes in the back pocket and isolation transformers used when significant voltage gets thrown around 🙂

 

[Diabolical Artificer]

WTF is being shown on this thread ?!

Don't look at this pic in that case. I've found prototypes like this work fine and whilst they look unsafe I know what I'm dealing with and take the usual precautions.

 

[LinuksGuru]

Corona at 500V? Tell me more?

I had corona at 490V after short. Spark ionized air and ignited corona.
Before that I'm also was sure corona can't appear before 600 - 800V.

 

[PRR]

was sure corona can't appear before 600 - 800V.

http://www.highvoltageconnection.com/articles/corona.pdf
http://www.highvoltageconnection.com/articles/corona_followup.pdf

 

[Diabolical Artificer]

I've had coronas when discharging caps but very short lived, oh and once at a posh restaurant with the port.

Andy.

 

[LinuksGuru]

http://www.highvoltageconnection.com/articles/corona.pdf
http://www.highvoltageconnection.com/articles/corona_followup.pdf

Yes, corona can appear even as low as only 300V.