Finally got a long-term 5F6A project done after some years of neglect. The cab had been waiting in the basement for the electronics to be done and, with a delivery from Weber on Saturday, I assembled. I hadn't left myself a lot of room in the cab and it took a few tries to figure out the order in which things had to go in. I finally got it done, powered up, flipped the standby and . . . it sounded like utter dookie.
This was not good but I was too tired to troubleshoot so I went to bed. As I tossed and turned, I realized that it had to be something to do with the speakers - the amp had sounded fine plugged into a 2x12 but with the 4x10s, it was thin, scratchy, ice-picky, nasty. This morning I plugged the 2x12 in and, of course, it sounded great. I unplugged the speakers individually and found that some combinations were better than others and so, out of lack of anything else to do, checked the phase at the plug end of the speaker cables that I had made some 10 years ago. Yup - you guessed it. 2 were out of phase with the other 2. Swap the speaker ends and - wow does this thing sound great. Too loud for the house, but great.
And, I know that it's the only one of its kind in the world - the amp that dares to ask the question "What if Leo Fender had asked Audi Stickley to design the Bassman?"