Tube amps and electric safety

[Svante]

HI all.
I have never built a tube amp, and can barely read the schematics of tube designs. I was just looking through the other thread with photos of home-built tube amps when I got to think of... Safety.
Are these things at all isolated? I mean, tubes typically operate at higher voltages than transistors, right. Yet everything is exposed to the fingers of curious kids. Or is there some secret layer of insulation that I don't see there?

 

[SY]

There's a whole thread on safety in the Everything Else category.

IMO, it is irresponsible to let kids near tube equipment; mine is behind a fence. The tube equipment, that is, not the kid. I tried it with the kid and got a nasty visit from Child Protective Services.

 

[Sch3mat1c]

Isolated: almost always. I've made a few designs that are line-operated, the first due to inexperience; the second (will have) input and output transformers and a grounded chassis preventing possibility of line contact.

As for the HV itself, you just don't get your fingers stuck in there! When (not if) you do, across just one hand or finger probably isn't going to hurt much (a few months ago I got 500V across my left index finger, felt just like 120VAC!) and certainly not be fatal; however if it goes between your hands, that's a problem.

Tim

P.S. Queue another monster safety thread... l8rz