[Mike O'Sullivan]

Nina wrote:

Hi Karl! Ya Know, this issue is a perrinial audiophile question that
has answers on both sides--and I have been on both sides. Now-as far
as tube equipment, absolutely do not leave on 24-7 unless you have an
innexaustble suply of replacement tubes and very good cooling
apperatum, e.g. fans.

I thought tubes (valves) lasted indefinitely if you don't switch off?
The frequent powering up and down is what causes them to fail.