Haha Don, you're asking about my top-secret H/K weapon LOL.
The A260 is easily H/Ks best integrated tube amp IMO. It simply detroys the later "Award" series amps (A300/400/500), but admitedly I'm a real sucker for 6L6GC sound (I'm currently using 7581A in it actually). I've restored several and have kept one real nice one currently in my office listening space coupled to a set of KG4s and it never fails to impress, even just from my iPod dock.The phono stage is especially nice. On a basic rebuild I simply "McShane" the power supply and recap the signal path. On my own unit I've also added individually adjustable bias, and a pentode-triode switch.
There are TWO versions of the A260 and the later version is superior (better power supply and output transformers) The easiest way to quickly to identify the later version is the presence of a 4th can capacitor top-side just forward of the RCA input jacks. The older version doesnt have this cap