Amp question

["Priest, Jim" <Jim.Priest@xxxxxx>]

Amp wizards, 

I just acquired a 1970's Fender Musicmaster amp, from the look of it in pretty much original condition: 2 x 6V6GTA and 1 x 12AX7 tubes, Fender 12" speaker, volume and tone controls, on/off switch, two inputs - that's it. Playing through my Astatic JT-30 it sounds OK-ish - plenty of bite though maybe not as much depth as I was expecting (but see below). I'd appreciate some advice on:
1. Is there anything to be gained in replacing any of the basic components: tubes and/or speaker ?
2. The tone control appears to have no effect, other than switching the volume off completely when I turn it down below 2. Is this likely to be something I could fix myself, or should I entrust it to an amp tech ? I'm moderately competent with a soldering iron and have worked on hi-fi amps (solid state) in the past, but am wary of the words of warning frequently issued here about the voltages hanging around inside valve amps.

Any advice welcome.

Jim