[R-390] R390A design improvement

[wli]

IMHO, the engineers at Collins in that era were outstanding for that era. Today, half a century later, there are many *improvements* due to advances in technology. The real issue is whether an owner wants to modernize his unit, or restore to its original design state. That is strictly a philosophical issue.

As for myself, I do simple things (a 12BH7A sub for the 3TF7) and stay away from front-end FET's. Of course, I ain't no engineer as Nolan used to say.

W. Li