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Zenith made a line of top-of-the-line chassis' in the late 1950 through 1963 that had switchable DC restoration from the front of the set. They called it "dynamic contrast" or "dynamic picture" as I remember it. It was a push-pull switch on the back of one of the picture controls under the screen.
Those same sets, while having only 3 IF stages, also used a new tube at the time. The 6EJ/EH7 was capable of much higher gain that previously used tubes, so they had wideband IFs with gain.
These were 21" and/or 23" sets. I've worked on a few when I worked in a service shop, and my great grandmother had one. I've never seen a better picture on a B/W TV set. In fact, I'd say those particular Zenith chassis were THE BEST monochrome chassis ever made, hands down, over and above ANY other manufacturer.
One other cool set I know of with DC restoration was the first Magnavox solid state or "astrosonic" large screen TV chassis. Introduced in 1965, it has DC coupled video amp stages, and most came with a 24" or 27" inch CRT. We had a stereo theatre in danish modern with this TV chassis, and the common astrosonic radio chassis of the day and a micromatic changer. It seemed to play forever with very little trouble, and still worked well when I got our first color set. I'd like to find one of those, but I've never seen another since the one my family had. I don't think they sold many as those with the money for a combo like that prolly went for color.
just my $.02.
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