Firing up old tube amps. Should I worry?

I did. They're monoblocks, so I had the speaker connected to the one I turned on.

Really pleased and surprised at how quiet these amps are after sitting so long. Was expecting some hums or buzzes. Really a nice warm sound with a good amount of punch.

This was a World Audio Design KEL-80 kit amp that I built back in the late 90's. Not even sure if they're still around.

Never heard of it. What output tube?

4 x EL-34 per channel, driven by a 6AU6 and a 5687.

Just take the equipment out in the driveway, put it up on cinder blocks, connect to the oldest and funkiest speakers you have, wear safety glasses, and have a non-liquid CO2 fire extinguisher ready to hand. No worries...

If you wait until the 4th of July to do this, you get extra credit for any sparks which may be produced during the process.

For a bit of a preview, go to YouTube and run a search for *4000W Tesla coil test" or "Vanguard (Flopnik)."

They just may not work...