[tubenutt]

Going through the papers I have(thanks to Chuck Schwark) for my 16B (code 121) the schematics indicate a 5Z3 as the rectifier, yet, I saw notes that say the (code 121) used an 80 instead.
Which rectifier will work best here?
The 5Z3 fils pull 3 Amps, plates put out 250 ma. The 80 fil pulls 2 Amps and the plates put out 125 ma. I would use the 80 in regards to the power trans, but will it (the 80) satisfy the DC current needs for 10 more tubes??!
And where, THESE days, can you find an original 80 or 5Z3 (hot branded) that isn't flat as Kansas?

[Chuck Schwark]

Not quite right. The Code 121 version uses a type 80, the Code 122 uses a 5Z3.

** Use the correct tube for the Code version of your chassis. **

It was a production change in later runs of the Model 16 and they obviously beefed up the rectifier to handle possibly the larger speakers in the console versions that required the output tubes to push a few more watts and the larger speakers had bigger field coils that took more current possibly. Guessing off the top of my head....

It could have been simple economics too. Philco maybe got a better deal on 5Z3s along the way and used them. Been known to happen with tube type changes for other models. Maybe Ron has thoughts on this too.

Chuck