These don't come up often and I want one!
https://vintage-radio.com.au/default.asp?f=6&th=321
I know it's a big call but these are probably the best performing CRT TV ever made. A real no-corners-cut design.
Basically Kriesler took the already-good Philips K9 and improved it.
For info
The au site is not responding for me, traceroute gets to Sydney and then times out.
Will try later.
Frank
Yes it can get a bit flakey at times. The owner hosts the site himself and he also heads up maintenance at a hospital so is a busy man.
Reading the first post on that page makes me wonder how many people bid for an old TV without any knowledge of how to get it working or of someone who does?
For me, the ultimate no-compromise design has to be the B&O 3200 with its separate EHT generator.
For me, the ultimate no-compromise design has to be the B&O 3200 with its separate EHT generator.
Well the Thorn 4000 has that too, but its geometry is poor by comparison.
I think if you can get a no compromise result without a separate EHT generator you have a better design.
I don't know the B&O, how close to perfect is it in other ways?
Kriesler competed in the top end of the market and sold to those who liked "furniture" pieces. Their main competitors were European imports that were generally not as good.
I don't know the B&O
I have one in my collection, see here.
Some further info here:-
https://www.radios-tv.co.uk/beovision-3000/
https://www.radios-tv.co.uk/beovision-2600-3000-3200/
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I think if you can get a no compromise result without a separate EHT generator you have a better design.
I'm not sure I agree with that; coming from a broadcast background the best-performing CRT monitors always had narrow-angle tubes (for geometry performance) and separate, regulated EHT supplies - any show with flashing lights ("Top Of The Pops" was a good example) soon showed up the limitations of sets with combined EHT and line stages, even when the HT rails were fed from solidly-regulated supplies.
In my area, the best-performing monitors were the Barco CTVM3 family (which had a separate regulated EHT supply): all other subsequent Grade 1 monitors were seldom as good.
Thirty-odd years ago I had a B&O 3200, but feeling very intimidated by it I dumped it. The second of those links provided by Chris gives a very good description of the set and what set it apart from its peers.
In the broadcast 4:3 and a little way into widescreen days I preferred the Sony BVM series over the Barcos, even though I have Belgian heritage;)
Yes the grade 1 monitors had to have separate EHT generation as dynamic EHT regulation would not be feasible.
Funnily enough I was just remembering a domestic TV model with combined horizontal and EHT that made a brave attempt at picture size regulation with just one resistor of a carefully chosen value. It certainly passed the TOTP test. Both timebases were fed from this resistor which followed a series regulator. On bright scenes, as EHT current demand increased, so did the voltage drop across the resistor. As a result both timebases' deflection reduced by exactly the amount of blooming.
As I said it would pass the TOTP test, but it would fail when with a bright sky with a dark scene at the bottom of the picture. There would be horizontal distortion but no worse than most other models.
The PD500/GY501 combination in the dual standard sets I saw had good EHT regulation at the cost of X-Ray problems and inefficiency. The first SS sets that used the tripler and valve line stages like the Pye 691 chassis were not as good in that respect. They changed the tuning from 3rd harmonic in DS to 5th in SS to try and improve regulation but it was still not as good. On the other hand it was perhaps good enough and I only ever had one complaint about poor EHT regulation from a customer.
Just goes to show if the programme content is good enough, small technical errors go unseen. Now we have 4K resolution TV with stunning picture quality and rotten programmes, well that’s my viewpoint.
Frank
Now we have 4K resolution TV with stunning picture quality and rotten programmes, well that’s my viewpoint.
It's so that the rubbish can be examined in greater detail Frank. 😉
To understand the black art of electronics is to understand witchcraft. Andrew.
In the broadcast 4:3 and a little way into widescreen days I preferred the Sony BVM series over the Barcos, even though I have Belgian heritage;)
Yes the grade 1 monitors had to have separate EHT generation as dynamic EHT regulation would not be feasible.
I never encountered the Sony BVM-series until the SD-SDI days: I can also remember some dreadful designs from one or two UK manufacturers!
Pye Firebox? 😱
They had been skipped by time I started work, but my seniors spoke of them with a mixture of fear and ridicule. EL509 line output stage with HT series regulated by 2x 6080 power double triodes, flyback overwind feeding a discrete selenium stick EHT quadrupler with ED500 shunt stabiliser (apparently, the steel screen over this nest of vipers could be replaced by a maintenance fixture of lead glass- "so that you could watch it catch fire" as a colleague put it....). Replaced by a potted assembly in due course.
I have a manual for its contemporary RBM colour monitor, this had a more couth and apparently more reliable set-up of PL504 line output valve whose pulses triggered a separate EHT generator with a PL509 and feedback regulation with PFL200 error amp and 85A2 reference and e-n-o-r-m-o-u-s 500M resistor sampling the EHT. Prosaically, this professional and presumably very expensive monitor used P-series valves in series string with their own transformer secondary so that a much more widely available valve series could be used.
You do realise that what you've named is the engineering equivalent of saying the name of "The Scottish Play", don't you?! 🤣
Yes, my older colleagues mentioned those things with equal fear and dread too. By the time I turned up, it was a mixture of Prowest and Melford in the older studios, Barco in the newer ones.
I'm told (though the story had probably passed down through several previous raconteurs, you may be closer to the origin than me) that one of the "Cambridge devil's-lanterns" that was slung from the lighting gantry in a studio as an audience monitor chose to self-immolate and, as no-one could work out how to get to it to extinguish it, everyone stood watching as streams of burning insulation slumped through the base ventilation slots onto the studio floor as if the strangest imaginings of Salvador Dali and Tim Hunkin had combined in smokey reality.
The Barco CTVM3 series were very good indeed when they first came to us (vastly better than the 17" Prowests with the dry joints and always-soft low-focus tube) but did not fare well being driven around the country and subjected to the inevitable wide-ranging temperature and humidity involved. I thought that the 3/51 would make quite a good home TV monitor when they went redundant, cooler-running than the tight-packed 3/37 too. Quickly eclipsed, though.
