In message , Michael Squires
writes
In article ,
Chris Morriss wrote:

I would say that you are more likely to damage the amp by using a 16R
speaker on the 4R tap, as this is going to cause larger than expected
voltage swings at the anodes.
--
However, the voltage swing can't be more than the B+ rail; the total
dissipation might increase.

Mike Squires

Don't try testing it under these conditions with square waves though, or
you will soon see voltages higher than the B+ rail at the anodes.

Don't forget that a transformer coupled valve amp is perfectly safe
under s/c conditions. It's an open-circuit load that can cause
flashover.


--
Chris Morriss