Hybrid colour sets using grid modulation of the CRT?

[toshiba tony]

In the 60s and 70s when hybrid colour sets were all the rage, happy days!
but which sets used grid modulation for the crt? This may seem a strange question but after a stroke and living with dementia odd things occupy my mind. I can only come up with three, I may be wrong, PYE697, Finlux Peacock and wasn't the Kuba Florence, again, I know it's an odd thing but thanks, ta.

[Nuvistor]

Bush CTV25, all the Pye hybrids, dual standard, 691,693 and as you say 697.

Philips G6 and Baird dual standard ??

[toshiba tony]

Yes the CTV25, best left in the archives of my fuddled brain.

[Hybrid tellies]

Most dual standard hybrid tellies, GEC single standard hybrid, Pye 691, 693 and 697 single standard hybrid chassis, Grundig Hybrid and solid state colour chassis right up to the 1980's, and the Korting hybrid and solid state chassis all used cda.

Point of interest most black and white tellies used CRT cathode video modulation. For some reason the excellent ITT/KB VC200 used grid modulation.

[toshiba tony]

Ah, yes, The GEC hybrid, the 20inch ones were great "little" sets, a bit cramped, who says I've got dementia!

[FERNSEH]

Didn't the Tandberg CTV1 have the RGB signals supplied to the CRT cathodes?
Three PL802 video pentodes used as the drivers.

Sets like the Pye CT70, 691 and GEC 2028 had colour difference drive, that is, luminance supplied to the CRT cathodes and the colour difference signals supplied to the CRT grids.

DFWB.

[toshiba tony]

Things are materialising, not every day conversation with my carers, ta.

[hans]

Originally Posted by FERNSEH

Didn't the Tandberg CTV1 have the RGB signals supplied to the CRT cathodes?
Three PL802 video pentodes used as the drivers.

Not being an expert on CTV1, but it seemed like the PL802 didn't last long. Did the RGB drive on the cathodes strain the valves more than colour differential on the grids?

[SunSPARC]

The Tandberg CTV1 uses RGB drive, via 3x PL802s, to the CRT's grids, not the cathodes.

The cathodes are all linked together and are only used for beam limiting and frame blanking. Line blanking is applied to the A1s.

Fairly unique, I think.

[Welsh Anorak]

And the scaricty of PL802s led to many being scrapped.

I suppose the use of CDA was because many of the early duals kept close to the Mullard data book. Obviously not Thorn who ploughed their own furrow, though I wonder if the mythical 1000 chassis used CDA?

Back to the CDAs, what about the Baird 700 and the ITT CVC1/2? Don't forget the Philips G6 that used three PCF200s. Produced a great picture as did the B&O hybrid that, of course, used a 12HG7 (!) luminance output valve and valved clamps (EB91s?) as well as the CDA valves. Kept the room warm (and engineers busy)!

IMHO CDA drive produced a warmer picture than RGB, more natural. I remember comparing a GEC 2028 (CDA) and a Thorn 2000 (RGB) side by side and I have to admit the GEC won subjectively.

[Nuvistor]

Originally Posted by Welsh Anorak

IMHO CDA drive produced a warmer picture than RGB, more natural. I remember comparing a GEC 2028 (CDA) and a Thorn 2000 (RGB) side by side and I have to admit the GEC won subjectively.

I agree some of the earlier RGB sets did not have the same picture quality as CDA sets. The Bush A823 chassis was not the best performer when put at the side of the Pye SS Hybrid. I saw few Thorn 2000 sets and only to watch not service and agree it was a really forward thinking but the picture was not as good as other CDA sets.

I think the earlier CDA idea was just carrying on from the standard USA colour set designs although by the later 1960’s the USA were innovating with new ideas. The CDA was tried and tested so possibly worth following for the first UK colour sets.

Later RGB designs seemed to overcome the problems.

[dazzlevision]

Originally Posted by Welsh Anorak

Don't forget the Philips G6 that used three PCF200s.

Then there was the Philips Swedish K70 chassis with CDA drive using PCH200s, if my memory is correct (model S26K497/15 was sold in the UK).

Wonderful picture AND sound (which also kept the room warm and engineers busy!).

[greg_simons]

Originally Posted by dazzlevision

Then there was the Philips Swedish K70 chassis with CDA drive using PCH200s, if my memory is correct (model S26K497/15 was sold in the UK).

Wonderful picture AND sound (which also kept the room warm and engineers busy!).

And an extra bottle in the line output stage, a PL504 along with the PL509 and PY500.
Greg.

[toshiba tony]

I only ever saw one working K70, most impressed. One of the best hybrids in my opinion, CVC five and nine came close though.

[MALC SCOTT]

Rediffusion had Luxor hybrid ctv sets in the early/mid 70,s Used 3 x EF184.

[Welsh Anorak]

Back in the day when PL802s were scarce wasn't it possible to use an EF184 with a pin cut off (!) as a 'get you home' replacement?

Another vote for the K70 - great picture and excellent sound. The white plastic back used to disintegrate so most were replaced with grey under a recall.
I'm still trying to find someone who remembers the 22" version with a curious spring loaded door that covered the channel selectors (why??).

[dazzlevision]

Originally Posted by Welsh Anorak

Back in the day when PL802s were scarce wasn't it possible to use an EF184 with a pin cut off (!) as a 'get you home' replacement?

Another vote for the K70 - great picture and excellent sound. The white plastic back used to disintegrate so most were replaced with grey under a recall.

Yes, CES/Philips Service issued a recall for the original white backs in their "Service Link/Link" publication, and they were replaced by grey ones at no charge.