correct way to turn off tube preamp

From a Manley preamp manual...
"7. Power up the preamplifier FIRST and allow it to settle for a minimum of 30 seconds before powering up your amplifiers. Turn off your preamplifier and source components LAST when powering down a system. This prevents amplification of turn-on transients and other noises when powering up or turning a system off and ultimately protects the speakers"

I'm new to tubes and got away with turning the preamp off first a few times. Then one time I heard this fluttering sound and then a pop. I powered the preamp back on and put on a CD and had no sound in one channel and a faint sound in the other. It turned out ,luckily, that I had blown 2 fuses in one channel of my amplifier and 1 fuse in the other channel.
You can do a Google search if you have a little time. That's how I found the Manley manual. It recommends, in another section, turn on sources first, then preamp...wait 30 secs, then amp and wait another minute or so before playing a source to give everything time to warm up a bit. Power off in opposite order.

Something else I've read is that you should always have a source connected to your tube preamp if the preamp is powered on. Same with a tube amp, that you should always have a load on the amp (speakers connected)if the amp in turned on.