Delta Gun Hype/understanding
 

Hello, I see many praises on Delta Gun sets.

For my own understanding, are all phosphor dot shadow mask CRT's Delta guns?

Also If i am correct, GE was the first to implement the three segmented rectangle phosphor vertical line CRT's, and Sony had a similar design in their Trinitron, but the vertical phosphors were not segmented. Both non-delta guns.

So that said, why does the general consensus lean towards preferring delta gun CRT's?

Let's see if I can explain this.... not all dot phosphor color sets are deltagun and not all stripe phosphor color is in line, but in TVs one can argue that it is the majority case. The first generation GE portacolor 11" CRT was an in line gun firing into what was basically the center 11" of a 21FBP22 deltagun CRT sliced out and stuck in a smaller cone. The Japanese market chromatron CRT (which was the Japanese taking an un manufacturable American design getting it as close to practical as possible then building it despite VERY high manufacturing dud rate) used continuous vertical phosphor stripes, and some used deltaguns. Shadow mask dot phosphor with in line guns was popular in computer monitors until the end of the CRT, and was used in some TVs. Breaking the stripe into blocks happened shortly after in line CRTs caught on in the US and IIRC had to to with imagine enhancement and black matrix technology (something Zenith rolled out in their deltagun chromacolor CRTs).

As for preference most TV collectors want sets that use vacuum tube or hybrid chassis, but not solid state... aside from the portacolor and Sony's the in line did not gain traction in the US untill just after the last hybrids we're being phased out... also at that time most of the last US TV manufacturing was being phased out so most sets of that period are seen as 15 year old wall Mart Chinese/Japanese garbage by collectors.

Neither technology was necessarily better or worse performance wise, but for the most part the era changed with the end of the deltagun.

Some folks like myself who don't officially collect solid state sets do grab SS deltaguns because the CRTs interchange with more desirable sets and by then were usually black matrix which is an upgrade....Also better SS deltagun CRT sets like the Zenith CCII were at least as good as a Trinitron, and last forever.

[B]The collectible color sets desired by many collectors comes from sets manufactured in the “Golden Age” of television. (1950’s) which used the delta gun design. Many, myself included, collect these sets for nostalgia. I grew up in the late 40’s and 50’s. Many folks say they prefer the color from the 50’s sets and indeed, RCA had correct NTSC phosphors in the 15GP22.

The early delta gun sets from the 50’s and 60’s are not superior to newer technologies of the 70’s through 2000’s, but it is amazing to see how well the 50’s technology looks today on a restored color set. [B]

The unbroken vertical stripes mean that the shadow mask is not self supporting and must be made of strips under tension (Trinitron). By using broken stripes, the shadow mask is self supporting, just like a delta-gun mask. A disadvantage of continuous stripe screens is that less area is avaialble for black matrix, so the screen is more reflective of room light. However, a tension mask can take much more beam current before going out of shape, so the disadvantage can be reduced by using darker faceplate glass and more beam current to make up for the loss in brightness.

The really big advantage in in-line gun tubes is the simplification of convergence and loosening of tolerances needed to maintain purity. The final result was tubes needing no complex dynamic convergence circuits, with all CRT adjustments obtained by yoke and permanent magnet adjustment. This sequence of development was a major factor in reducing color TV prices in real terms. While general inflation went up by a factor of 7 to 10 times, color TV set prices stayed constant or actually declined. There was a long period when the common color TV set was a 19 inch table model selling for about $300.

A slight correction - the Trinitron fine horizontal wires were added to reduce vibration of the vertical wires, not to alleviate effects of heating. The Trinitron vertical wires were under tension until heated very excessively, which normally could not happen with the current densities that could be reached in a normal chassis design. Edit: on large Trinitron tubes, knocking on the face would vibrate the grille, and you could plainly see the effects of the grille wires ringing.

Self-supporting shadow masks were subject to local expansion if there was too much local current, like the white patch in composite color bars/white/I/Q pattern. This could not happen with the Trinitron tensioned grille or the later Zenith flat tension mask tube. Self-supporting masks also were subject to overall expansion due to average temperature, and mounting techniques were developed that moved the mask closer to the phosphor screen as it warmed up and expanded over-all, thus maintaining design aim-point beam landing and good purity.

I can see the horizontal wires preventing vibration, especially in field monitors, but knowing that a shadow mask or aperture grill heating up and warping slightly could cause mis-registered color, it seems likely the tungsten wires also helped prevent warpage. Your comment about the slot mask connections make sense to prevent warpage.

Edit: I stand corrected. The aperture grill will warp, but not in a way that cause mis-registered colors, so I guess that’s another advantage over delta gun CRT’s.

The Trinitron grille wires could not warp because they were under tension. If you managed to really overheat them to the point they lost tension, they would become loose, like strings that are too long for the size of the frame. It was not only the thick glass that made Trinitrons heavy, but also the grille frame that was sturdy enough to maintain tension, just like a piano frame. Self-supporting shadow masks were not under any tension, just had enough strength to maintain their own shape due to the compound curve (same principle used to make auto bodies, where you never find a flat surface).

Got it. Took a while to sink in. :D

When I worked at the tv shop a Sony KV-1920 came in for a repair and the jug was in need of replacement. That was my first set into the wonderful world of Trinitron. Our only other color sets were delta tube/shadow mask technology. I bought the Sony as the customer didn't want to fix it. The shop got a new jug from San Diego as their CRT plant was opened by then. The tv sat unrepaired for a long time as it needed the usual parts that would be taken out when the SC613 would fail. It needed SG613, HO transistor, and new style top hat damper diode. But after having that Sony finally working I became a true Trinitron follower and never looked back. Next set was a Sony KV2648R. I joined Videokarma when the 2648R died. I still have the KV1920 and it is operational, but needs a restoration if I were going to use it daily. I'm probably an oddball collector that only has one delta tube set. A 1968 Zenith color console, all tube. Everything else I collect will be a Sony product. That's how much I respect the Trinitron technology. Partly because I don't have room or time or space to collect anything that's large. I appreciate all the delta sets I see on here, but won't be collecting them. With about 20 sets I'm seeing a space issue. I just wish the CRT technology would of lasted longer. :tears:

It didn't make it to 4K/8K, but it did make it to HD...I've got what I consider the ultimate Trinitron (KD-34XBR960 WEGA with a 16X9 Super-Fine-Pitch CRT that supports native 1080i HD) as my daily HD set/media PC monitor...At nearly 200lbs it aint exactly fun to move (though I can pick it up and walk with it), but it is probably the best compromise between wanting to watch a CRT and see HD video as you'll ever find...Flat panel sets for years after it was made were still not beating its contrast ratio, brightness, and color fidelity.

https://en.wikipedia.org/wiki/FD_Trinitron/WEGA

These things can still be found for under 50 clams if you watch the used market (they have a following with gamers and some other circles).

I’m convinced that the Trinitron (which is really an improved Chromatron) was the best CRT period. I saw the first two in 1968, bought both and never looked back with the exception of an RCA 38 inch HD 16x9 set, followed by the Sony 36 inch, 16x9 HD XBR. I didn’t have to buy many Sony’s because they just last.

“Flat panel sets for years after it was made were still not beating its contrast ratio, brightness, and color fidelity.”

WOLED sets surpassed the best CRT’s.

I did write that in the past tense to indicate that flat panels have bested it...

I once had a Sun Microsystems monitor with the super fine pitch, flat screen Trinitron. It was fantastic to say the least. It had so many convergence adjustments that it was darn near perfect to the very edge of the screen. Yes, it was very heavy. I was sad to see it go, but the LCD display that replaced it was much less bulky and generated much less heat.

I can still feel a tinge in my back from moving those large Sun branded Sony monitors :S

Back around 1984 I was working on 1024*1024 32 bit graphics systems. This was really exotic back then with cages full of massive cards and hefty 5V PSUs.

The company was using delta gun CRT monitors with these brutes. ISTR they were Mitsubishi. It was exceedingly difficult to get these monitors purity and convergence good enough for the high end graphic arts stuff we were doing. Nightmare would be a good desciption. They said they had tried an inline gun monitor but it wasn't good enough.

Apart from re-designing the graphics generators to lower the cost, my job was to evaluate the latest monitors and prove they were up to the job. I settled on a Barco high resolution jobbie with inline guns. Can't remember if it had dots or stripes. Purity and convergence were a doddle, generally OK out of the box. All I had to do was convince the picky arty types that they were at least as good as the delta gun monitors. It was blatant to anyone that they were good, the only weakness was that the absolute resolution was a fraction worse than the delta guns.

The production and test people were grateful for the change. Basically if the new monitor looked right, then it was right. No more finicky purity measuements with a colour analyser and seeing if the result was within tolerance.

Since this thread is about the delta-gun types, there is something that I have always wondered, which was / is the better CRT from a technical / longevity standpoint?
The roundies or the rectangular types?
Granted, you lose a small % of the pic with the roundies, but I don't even think it was really noticed much in it's day.

1024x1024 32 bit? in 84?? had no idea they had that back then...

in 84, i was a very VERY young kid, playing games in 320×200 in 16 colors, on my dad's ibm 5150

Compu 85, did Sun build those monitors or did Sony build them and slap a Sun nameplate on them? I had the back off once and there was a ton of electronics in there! No wonder they were heavy. We had a company rule that it required two folks to move one.

I'm pretty sure the round CRT shape with the spherical faceplate was used because it has lesser demands on the electronics and the CRT hardware for purity, convergence, and pincushion distortion. When Motorola started making sets with the first modern rectangular tube, the 23EGP22, they had to include extra circuitry for pincushion correction. I'm sure there were changes to the convergence circuits as well since this CRT had a flatter faceplate than the 21" round tubes.

As far as longevity goes, that's more a matter of materials, manufacturing, and end usage by the customer than the shape of the CRT. I would say that on average the later CRTs should hold up better since they had more efficient phosphors and therefore didn't need to run the electron guns as hard.

Longevity huh? If it's shelf life they are probably all comparable. If it is power it up for as many hours as it takes to burn the cathode off the gun Zenith Delta gun rectangular sets from 1970-78 (chromacolor black matrix era) probably take the prize. The CCII chassis that drove them were nearly immortal too. Some of those sets were found by fire fighters after house fires with the plastic melted and speaker cones burned out still showing a perfect picture under the soot stuck to the screen. Many still work as found today and some of those were in continuous service since new.

Correct. Rectangular sets required at least third harmonic horizontal-rate dynamic waveforms in addition to the sawtooth and parabola of the roundies. This adjusted the convergence midway between screen center and the left and right edges.

By the way, the 23EGP22 screen aspect ratio was narrow - 1.27:1 instead of 1.33:1 (4x3). This allowed a longer horizontal retrace time without producing black bars left and right or making people look fat, which in turn reduced the peak retrace voltage on the horizontal output device. It was barely possible to produce reliable horizontal output transistors (with the required "safe area" of voltage and current), so every little bit helped.

Only in VERY expensive professional kit. Think $250,000+ range. The hard discs were removeable packs sitting on drives the size of a washing machine. The computing power was bit slice processors for the graphics manipulation backed up by some kind of PDP11.

A few years later you could run photoshop on affordable kit.