It has blue labelled speakers,ceramic magnets with baskets that look like CTS.The stampings look like CTS to me,but I'm no vintage expert.They may be Utah too,but who cares?They sound delicious.
This amp has all the original RCA tubes as well,which likley contributes to some of the sweet tone.
It likely has been sitting in somoeone's studio or bedroom for all these years,cause it has no battle scars at all and it looks like it rolled off the showroom floor.
Not all silverface amps were bad
The transformers and parts inside this amp are all just as good as the blackface amps and the lead dress is not that bad compared to the master volume amps.
I have one of my clone amps here to compare the tone too and they are pretty similar,both amps are sweet sounding,with my clone having the edge for bottom end and earlier breakup.
However the similarities stop there,cause my clone has EL34's(glassier tones) and a growl control so it's more versatile.It has a couple of P10R's.They sound pretty much the same as the real vibrolux does which is surprising.
The EL34's don't alter the tone as much as you might expect,but they are glassier sounding with open chords.I'd actually give the overall edge to my clone cause the blackface circuit is better sounding.
I need to resist that urge to blackface this amp!!!I never seem to be able to leave stuff alone!