guitar speaker/tube challenge redux

[Harry Bissell]

There may be a danger from fusing the plate circuit. When the fuse does blow,
it will suddenly interrupt whatever current was flowing in the output
transformer... which will have noplace to go. The voltages will tend to
infinity until they find a path to take. This might arc the transformer etc...

:^) Harry (not a tube expert but plays with large tranformers...) Bissell

"J. Larry Hendry" wrote:

> > 2) Martin Czech wrote:
> >
> > >  How can one destroy a tube (without an elephant sitting on it)?  Too
> much
> > >  anode current will make the anode glow (good idea to look at it), but
> > >  amateur radio people said to me that the tubes can stand that for a
> > >  while (a bipolar transistor or mosfet will die very soon if the SOA is
> > >  left so far behind). Tubes can also withstand very large anode voltage
> > >  transients/overstress compared to transistors (2nd breakdown,
> snapback).
> >
> > >  If you do something wrong to a tube amp, either a cap or a transformer
> > >  will blow, tubes die slowly (my own experience and that of my amateur
> > >  radio collegues, perhaps radio tubes behave different from "audio"
> > >  tubes?).
>
> Seems like a slow acting fuse in the plate circuit might be good protection
> for expensive output tubes Anyone ever seen a tube circuit fused that way?
>
> Larry Hendry