#1
So I posed this type of question a while ago, but part of my question wasn't answered.

I had asked for info on decent, and decent priced, power attenuators or dummy loads for my Crate V33 2x12 (I Bought the amp for live and jam purposes, but it's nice to be able to use the amp in my room sometimes without blowing out neighbours).

So, as far as I know...

- Turning on the pre-amp without the power-amp/speakers connected, this can fry the tubes and amp...
- I have a 2x12 speaker configuration (with two speaker plugs, of course)
-Attenuators only have a one speaker input.

Question: If I'm only connecting one speaker, what effect will this have on my amp?
#2
- Turning on the pre-amp without the power-amp/speakers connected, this can fry the tubes and amp...
You can't actually do that. Any time you have the preamp on, the power amp is also on. If you're using the preamp out, say to a DI box, it's fine- but then there's no reason to disconnect the speaker. Basically, don't ever run your amp without a speaker or a dummy load connected.
- I have a 2x12 speaker configuration (with two speaker plugs, of course)
-Attenuators only have a one speaker input.
Wire the speakers for one input jack. You don't have a stereo rig, it won't affect anything. If it's a 2x12 combo it will already be wired that way so I'm not entirely sure what you're talking about. You can always put a switch in to turn speakers on/off.

Question: If I'm only connecting one speaker, what effect will this have on my amp?
If the speaker can't handle the output of the amp, you'll fry your amp. If it can, you just have to adjust for the ohm difference.