Re: Can you?
I've got a pair (of Yellowjackts, that is) that I run in my Traynor from time to time. Not totally sold on them, but they do work as advertised without a hitch -- another sound, totally reversible, and no ill effects to the amp.
The one thing I was disappointed with was that they do nothing to change the overall character of your amp. I know now that's too much to ask. But it doesn't make my crunchy YCV50 Blue sound like a chimey Vox, so much as just move the voicing from lower mids to upper mids. YMMV with a different circuit, but the transformation wasn't as drastic as I'd hoped.
Basically, if you want a different sound and lowered wattage, though, go for it. THD makes good stuff.