Ok, I was not sure because you responded to the post that was everything about Lankford.
I started out chasing the problem as a common mode problem, when I should have looked for a noise source first. But in the process I fixed two problems in my radio. I resolved a lot of problems today and my radio no longer has any buzz, on the other hand the only buzz it had was picked up by the antenna. I have an outdoor light with an IR detector, it creates a terrible buzz, also found my garage door opener creates some buzz. They are both on the same circuit breaker. I very small amount of audio buzz was left but not enough to show on the S mater. I found that an isolation transformer with the ground lifted gets rid of that. So with all that taken care of, buy shutting off the breaker, I can hear 200kHz beacons, AMBCB, 80 Meters, 40 Meters, 10 Meters and CBers on
28MHz, so the amp is wide band and working.Mikek