Quote:
Originally Posted by dtvmcdonald
Look carefully at both the CT-100 DC restorer circuit and the results on screen.
It does not do full DC restoration .. by intent! Its, if I remember rightly,
somewhere between 75 and 85%. This produces a bit extra brightness on
dark scenes, which the customers actually liked better. In fact, **I** still like it better, even in my dark room.
|
The CT100 DC restorer discharge path is 1M ohm, and the charge path looks like about 10K ohm, which appears to be 99% DC restored to me.
I stand ready to be corrected if someone can detail how this circuit could produce only 85% restoration.
Later sets with luma drive to the cathodes typically had deliberate ~85% DC coupling, which Consumer Reports complained about for years. Later solid state sets, especially those with video analog ICs and auto tracking, had 100% DC restoration, which stopped the complaints.
The CTC-5 super chassis (the cost-cutting disaster) had less than 100% DC coupling in the color difference outputs also, resulting in reduced saturation in an all-red image, for example. This was probably done to reduce tracking shift when replacing demodulator tubes.