Originally Posted by dieseljeep
The later CTC7's and CTC9's and later went with voltage doublers and silicon rectifiers. The CTC16 was the first to use full wave bridge and higher voltage secondarys on the transformer.
You're right, the later 7s and 9s used the silicon rectifiers.. It's been a while since I worked on a CTC-9. The selenium I was thinking of was the weird three section unit in the convergence section. Mine was bad at the start of the restoration