RCA CTC-5 Deluxe Chandler Restoration

[etype2]

Here is a link to the progress thus far.

https://visions4netjournal.com/vinta...-tv-page-twoa/

I wonder who the gentleman from California was?

[Penthode]

I like the CTC5 Deluxe. Next to the the CT100 and 21CT5, it was the last RCA Color TV with more than 500kHz chroma bandwidth for many years. It has two stages of audio IF for better quality sound. It misses the simplicity of B&W setup and convergence of later sets but it can be a good performer.

[Username1]

.


Light that sucker up right now, see what it does as is......
Maybe there's still an old Ed Sullivan Show stuck in the tubes & needs to get out....


.

[old_tv_nut]

Originally Posted by Penthode

... it was the last RCA Color TV with more than 500kHz chroma bandwidth for many years...

Interesting. I would have expected it and all the following sets with X/Z demods to have about the same chroma bandwidth.

[Penthode]

Originally Posted by old_tv_nut

Interesting. I would have expected it and all the following sets with X/Z demods to have about the same chroma bandwidth.

If you look at the chroma section in the Deluxe chroma demodulator design, the lower chroma sideband response extends to about 1MHz. This means that there should be a degree of quadrature crosstalk but providing more resolution in the I vector direction.

I recall a 1955 issue of the RCA Review I read decades ago, long before I had a chance to examine the CTC5 chassis. I recall they did a study allowing a degree of quadrature crosstalk and I wonder if the Deluxe chassis was an attempt to justify the addition chroma resolution at the expense of the crosstalk?

Interestingly, subsequent RCA sets stuck with the 500kHz chroma response.

[old_tv_nut]

Thanks.
If i recall correctly, much later Zenith solid state sets used a simplified color bandpass that consisted mainly of a compensation circuit for the IF rolloff, with a not very sharp lower edge cutoff that allowed decent color resolution with some quadrature distortion.
Designs that try too hard to get max bandwidth with no quadrature distortion will suffer from ringing chroma transients, which can get worse than the quadrature crosstalk if the cutoff is really sharp.

[old_tv_nut]

By the way, if the response is significant in the lower chroma sideband, I would expect the DeLuxe to have more cross-color than subsequent sets.
Once it's restored, it would be interesting to compare the effect in the Indianhead resolution wedge to a Super or a later RCA. Come to think of it, I've never looked at this in a CT-100 - would be interesting.