dedicated electrical line

You don't *need* to install a dedicated line. The amp will run fine as long as you don't have a bunch of other equipment or appliances plugged into the same circuit.

On the other hand, a dedicated line typically will *improve* your sound, and many folks consider having several dedicated circuits providing power to our audio systems to be a starting point for achieving the best sound possible in a given system.
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dedicated lines will help any audio equipment not just tube amps. i have a dedicated line for my front end and one for my amps. it will stop you from having all of those other electrical devices you have in your house on the same line making all of that noise. it will make a tremendous difference. by far one of the best things i have done for my system's sound

your correct the amps will run just fine without them, but you would not belive what happens to the noise floor when you enstall them. it is quite amazing

As stated above, dedicated lines - I have one for front end componentes and one for amps - will do more to improve your system than any "add on" electrical isolation components and are far cheaper than most of that stuff.
Best to talk to an electrician electrical contractor.
My advice - talk to more than one and get some prices to compare.