I am still searching for the right answer to utilizing my fender blues deville 4-10 at practice without being too loud. Isn't there a way to get the amp cranked up enough to provide good tone and yet have control over the volume? Is there an electronic device I can use for this like an intinuator?
Look into attenuators.
THD Hotplates are one.
I have a Weber Mass that I use.
Look them up on the web and didnt you already post something about this. I think I suggested the Weber and someone else mentioned the THD. They are both good units and will do what you want. They arent cheap, the Weber was around $250 dollars, Im not sure about the THD, but I think they are in the same range.
Another option is to mic the amp and cover it with a heavy blanket or put it in a closet. Your guitarist will not like this cause it wont feel the same but Ive done both of these and it works.
What Fenders Ive used ussually need to be cranked on up to work properly.