On Thu, 04 Nov 2004 19:25:34 +0000, Keith G wrote:

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

It's not like they are going to burst open, is it??

Also does quick 'hot-swapping' speakers while an amp's hurt it any? (Oi
dun a lot o' thaat in tha parrst.... ;-)

If you want to do some speaker swapping turn the volume right down
or, better, switch to standby (HT off) while you do it. That way the
output stage won't be driving into the open load and it will be ok.

Running a signal into an open load can do a few things:
1 - nothing (quite possible as some circuits put sufficient load on
anyway, or you may have insufficient signal to cause a problem).
2 - internal arcing in one or more valves - usually ok.
3 - insulation breakdown on one or more turns on the output transformer
primary. If this causes one or more shorted turns (quite possible) then
the tranny is usually dead. If it causes an open circuit then it is
definitely dead! It probably won't look damaged though.

--
Mick
(no M$ software on here... :-) )
Web: http://www.nascom.info