biggest direct view CRT B&W (30 inch) ever made

[wa2ise]

Was surfing around and found this web page (earlytelevision) about a DuMont B&W TV that has a 30 inch CRT. click here

I've heard that CRTs using a big cone of metal and a glass face plate tended to fail often. Yes? Also, does the very high voltage get applied to that metal cone? Nice shock hazard for the repairman... The 30BP4 wants 22KV.

30 inch CRTs, this one a 30BP4 must have been really expensive.

[Eric H]

If by failure you mean losing vacuum, maybe.

This was a big problem on the Color CRT's, however I have several 16" B&W composite tubes that are still intact as far as the vac goes, one is NOS and sat for 50 years before I got it and it still checks like new.

A 30" tube would pose more of a sealing challenge I suppose.

[rca2000]

At Steve's place, the ETF museum. I played with the controls, and watched the vintage programming on it. with the I was impressed with the size of the set,roughly the size of a 46" big screen tv, and probably 500 pounds or more(with all of that wood). Steve also has a 30bp4 tube on display, in the room with vintage crt's

One thing that does NOT imprerss me, the set only has ONE 6v6 amp for the audio. Now, the 6v6 is a great tube, but with such a monster set, you would think it would have been push-pull 6v6's

[Tubejunke]

Wow, those Dumonts sure were some beautiful sets. I had an RA-109A that I got back in 1983 when I was taking electronics in school and becoming interested in the still very plentiful tube sets. The set followed me through to life in my current home, with the help of a refrigerator dolly. With other sets and limited space I was forced to keep it out in a shed and some exposure to the elements. The power transformer on those things was probably 30 pounds. Biggest I've ever seen. I always loved watching the 40 or so tubes at work. Neat the way they used dual low and high voltage rectifiers. Tough stuff!! I had to give the set to a fellow collector with space and funds for proper care and restoration. I felt it was the only right thing to do. Even the electronics museums would not buy her from me. The biggest drag with these old sets is shipping problems and cost.

[Eric H]

A while back there was a 43" Sony pro monitor on eBay,
supposedly the biggest direct view CRT set ever made.

He had a 1947 Pilot 3" sitting on top of it and it was dwarfed by that monster!

[Sandy G]

I have a book "The Cathode Ray Tube" & it talks rather at length about those 30" Dumont CRTs. Apparently, it was quite a feat making them w/the relatively primitive technology of the day. They gave some trouble, & Dumont made 2 runs of them before giving up & offering the owners of the "Royal Sovreign" sets a 27" replacement. -Sandy G.

[domfjbrown]

BLEEDING HECK!!!! That thing is huge!!! I've seen a Goodmans 33inch colour TV (yep, I'm British) in the flesh and that was large, but a B&W set? Woah...

I'd not want to be near that if it imploded....

[Steve McVoy]

Not only was the 30 inch tube the largest B & W tube ever made, it was the first 90 degree deflection tube. At that time (1951), 50 degree tubes were common, and 70 degree tubes were just being introduced. DuMont was always a leader with large screen sets - they made 14 and 20 inch tubes for their prewar sets in 1939 and 40, much larger than the 5 to 12 inch tubes from their competitors.

[Sandy G]

Yep. I remember seeing a pic in an old book about TV somewhere & there was this rather unhappy looking model holding both a 14" & a 20" Dumont CRT from 1938. They looked extremely fragile, & while she was smiling, you could tell she'd rather been just about anyplace else. Imagine posing w/one of those 30" bad boys....-Sandy G.

[domfjbrown]

Originally posted by Sandy G
Imagine posing w/one of those 30" bad boys....-Sandy G.

...and then it dropping on your foot and imploding - scary stuff....

BONGSKLAAASH!!!! Nee naa nee naa etc etc!

[Sandy G]

That 30" CRT was a metal cone design, & was almost big enuff to be a kiddie wading pool. I wonder how many of 'em are still around? Probly more rare than CT-100s.-Sandy G.

Most of them went to restaurants and country clubs - the cabinet was too big to fit through the doors of most homes. I'm guessing that maybe 200 were made. The price must have been astronomical, even in 1951.

[Steve McVoy]

Crosley also made a 30 inch model. One was one Ebay last year and was purchased by a collector.

[andy]

...

[Tubejunke]

My old RA-109 that I previously mentioned was purchased from a local antique/junk dealer who happened to be the original salesman and owner of our first television business. I remember him telling me about unloading the thing in like 1947 and how it was so expensive that the owner of Stanley Furniture Co was one of the only locals who could afford it. I think he said the thing was like $1000. I could be wrong. When I found the set in a shed with a leaking roof it had seen better days but was complete. I wish I could have kept the beautiful set. I would like to own a table model roundie Dumont but I will probably never run across one. I have a Sparton from 1951 or so and it is another exceptionally well built set. That thing has never been restored and has never failed to be a watchable set. I will admit that its starting lose vertical height after 30 min of viewing. Very crisp CRT and excelent reception. These are the two toughest and most interesting sets I have owned or seen. I think Capehart is another toughie but I have never owned one.