"Nick Gorham" wrote in message
...
Fleetie wrote:
"Wally" wrote

Keith G wrote:

OK, exactly why don't trannies (on valve amps) like it being run
without a load?

I think it has something to do with the xformer's secondary trying to
drive
a very large impedance (ie, open circuit). I think this translates into
excessive current in the primary (but I could be wrong).


I'd have thought quite the reverse; usually, I'd have thought the
primary current would decrease when the load was removed from the
secondary.

Yes, it will, without the reflected load the primary reverts to effectivly
choke loaded. But the secondary is still a inductor, and so does what
comes naturally to it.

Think about how ignition coils in cars work, its the rapid di/dt that
causes a high voltage.


Mind you, if there's feedback and so on happening round it all, goodness
only knows.


Its not a feedback issue, just inductors at play.



OK, tells me not a lot other than it's probably not too damaging if it's
quick and there's no signal present??