Imo get rid of the speakers. They are not efficient; they are like pushing a brick, like a Magnepan. It would take a crapload of power/current to make them sound lively. By looking for an inexpensive tube amp you are setting yourself up for marginal improvement. They are, of course, lovely in terms of nostalgia, but there are far, far better speakers now. You can do so much better in terms of speakers.
Don't fool yourself into thinking the speakers are "all that". If you want a sea change, change the speakers. Or, rip into them and redo them, from crossover to internal wiring to drivers. If you love their appearance that would be worth it to you. But it won't help with valuation of the speakers.
Don't expect miracles if all you do is change amps. You would get much farther overall by changing speakers, imo. Your current electronics with a more efficient speaker would be revelatory to you. :)
