Just out of curiosity does anyone have any insite as to why RCA used selenium stacks in the CT100 thru CTC4 series instead of 5U4s?
Starting with the CTC5 and going forward, RCA switched to using 5U4s.
Data sheet for 5U4 indicates it will produce 225ma of dc current. I don't know what the ratings of the selenium stacks are, but my measurements indicate that a pair of 5U5s in parallel would be enough to supply the 440ma I measured in my CTC4. And further, the B+ fuse in the set is 450ma.
Here is a link to the technical data for an RCA 5U4. I must confess I'm not much good at interpriting these graphs.
http://www.mif.pg.gda.pl/homepages/f...49/5/5U4GB.pdf
Do you think this was an issue of reliability/pushing 5U4s to their upper limit, or cost in manufacturing considerations?
