Quote:
Originally Posted by old_coot88
If by 'wacky power rectifiers' you're referrin' to the dual 3DG4s (3DG4 is sort of a 'hunkified' 5U4 with different basing), Zenith probably considered them more robust and reliable than Si diodes of the time. That'd be my guess.
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Some Zenith TVs of the late '50s-'60s used one 3DG4 as a low-voltage rectifier, but I've never seen a Zenith with two of these tubes in parallel. I once owned a 23" Zenith b&w console which used only one 3DG4 in the LV power supply. The only reason Zenith would have designed a TV to use two of these tubes, IMHO, would be if the TV were a 3-way console, with a record changer, AM-FM stereo radio, and a very powerful audio system (as most of the combo Zeniths probably had). I cannot see the sense or reasoning in using two rectifier tubes for just the television chassis.
BTW, aside from the Zenith TV I had, I've never seen any other TV (Zenith or any other make) which used the 3DG4 as a LV rectifier. As I said, I think the reason Zenith designed some of its TVs with two LV rectifiers may have been to handle the additional current requirements of sets with powerful audio stages, such as their 3-way TV-phono-radio consoles. The use of two 3DG4s in the LV supply of any kind of TV other than a 3-way console, IMHO, would be overkill; after all, why on earth would a TV, and just the television (no record changer or radio) draw so much power as to require two LV rectifier tubes?