I have a dilemma and am once again seeking advice.

I have a Sears Silvertone amplifier. It dates to the early 60's. Here is the dilemma. It needs new tubes, which I can replace through E-Bay. Since it is so old I wonder if I am taking a chance on blowing the transformer by replacing them?

I doubt I could find another transformer. Part of the sound of the amp is because of the old tubes. Sure would hate to destroy one of my prized possessions.

Help!!!!