I believe Tom is still going, though by all accounts he is not working as much as he used to. A phone call may well be best.
It's worth noting that Art amplifiers are quite readily serviced by anyone who properly understands valve hifi. Component specs are important, as Tom is rather fussy about certain parts. However, the actual circuits are straightforward, though with some interesting aspects here and there.
Of course, that all assumes anything needs doing to it. If it's 'right' it ought to sound very decent. If it's running triode strapped, though, bear in mind the output power will be about half that quoted for the standard amp. If there is a degree of negative feedback in the original amp, distortion (though mostly relatively benign even-order harmonic) may actually be higher, though the amp will run more smoothly into soft clipping.
