Thanks for that explanation Richard. I see what you mean! It's accumulative in fact although, as they say [in Lancashire at least] "It all mounts up!". I think I've gained my impression of this from reading about Radio or Tv set restorations, where the person trying to revive things often talks about a generic problem with certain valves needing a four amp supply and has to cobble something together [separately] to make up the difference
Dave W