The rewound output transformer (the one on the left).
Though never being a big Fender fan, I can understand why they are so popular with guitarists. However, an even worse pet-hate of mine is the use of printed circuit boards in tube amplifiers! Still, it is a "sign-of-the-times" and I have to live with that! I have to say that at least this Twin-Amp has all the facilities on the back panel. You don't have to remove it from the case to set the bias etc!
Quite neat for circuit boards......I suppose......really.........
Apart from a handful, most Fenders don't actually seem to reach their quoted RMS output. This is one of the exceptions, making the full 100 watts & from a set of Mesa-Boogie 6L6's. (Well.....Russian ones really, re-branded!)