Huh?

[Eric H]

"Was actually designed prewar and put on hold till after armistice"

http://cgi.ebay.com/ws/eBayISAPI.dll...&category=3638

Aren't they confusing this with the 621-TS?

And what's with the massive power transformer, did (does) Canada use something other than 60 cycle power. (paging Rob )

[Rob]

Eric,

I remember as a kid growing up in Toronto that they changed from 25Hz to 60 Hz sometime in the early 60's before 1964. The power company replaced the compressor in my parent's fridge and that of my grandparents during that conversion. I guess they did everyone's. That must have cost them a fortune!

Unlike electric motors though 25 Hz power transformers if anything actually run better on 60 Hz.

That huge 25 cycle transformer sure looks strange in that 19A11. As for pre-war design shelved? I don't subscribe to his theory.

Some of my 40's Admirals have the 25 cycle power xfmers. There will be extra supply filtering and circuit changes in the sync detector so that the set's vertical oscillator won't be fooled by 25 Hz mains.

Can you imagine UPS shipping that set? One drop kick and that heavy iron would launch right through the bakelite case.

Rob

Originally posted by Eric H
"Was actually designed prewar and put on hold till after armistice"

http://cgi.ebay.com/ws/eBayISAPI.dll...&category=3638

Aren't they confusing this with the 621-TS?

It couldn't have been a prewar design, because many of the tubes didn't exist then. RCA was able to design the 621-TS DURING the war because they were manufacturing military electronics, and were creating the very latest miniature tube designs, such as the 6J6, 6AG5, & 6AU6. These types were released in 1942 and were originally used in radar & other HF military applications, but were also made available to the TV design engineers. This made possible the 621 design, which had low noise RF & IF stages, 21-25 MHz IF (vs. 8-12 MHz in prewar designs) and the first tuner that could operate on high band channels.

[Marlin Mackley]

"...One drop kick and that heavy iron would launch right through the bakelite case. ..."
Rob:
You are quite right. I won one of these 25 cycler's maybe 2 years ago, "restored and working fine", but by the time the UPS finished bouncing it around it did not work right. No actual visible damage, but it acts like something in the Horiz sync got knocked loose. I never had time to fix it so it is still ill. That is one heavy set for a 7 incher!
Marlin

[Steve McVoy]

Actually, the 621 couldn't have been designed before 1945, since the developmental version of the 6BG6 horizontal output tube wasn't released until late 1945. The cabinet may have been designed earlier.

The 621 and 630 were introduced at the same time, in November of 1946.

[Rob]

Originally posted by Steve McVoy
Actually, the 621 couldn't have been designed before 1945, since the developmental version of the 6BG6 horizontal output tube wasn't released until late 1945. The cabinet may have been designed earlier.

The 621 and 630 were introduced at the same time, in November of 1946.

Steve,

Put an 807 beside a 6BG6G and except for the base I'd be hard pressed to tell the difference, except for the box on top of the cathode. Wasn't the 807 used in really early designs before 6BG6's were available? I made a socket adaptor and have actually put an 807 into a socket wanting a 6BG6 in my first Admiral. This was early on in my collecting and I had no stock of 6BG6's. It worked but the 807 didn't seem to have as much gain.

Rob

[Steve McVoy]

Yes, the 807 was used in some early GE models, which were replaced with the 6BG6 in later production runs. It is possible that the 621 was designed before 1945 using the 807, but I doubt it. RCA, along with every other electronics manufacturer, was concentrating on war development until the war started to wind down in 1945.

I have read that although manufacturing of TV sets came to a complete halt for the war effort, TV research and design continued unabated at RCA & DuMont. The image orthicon tube & camera were developed during the war, and were first demonstrated in 1944. These companies wanted to be ready to roll TV sets off the production lines at the earliest opportunity. DuMont began manufacturing the first postwar set late in 1945, beating RCA to market.

Originally posted by Rob


Steve,

Put an 807 beside a 6BG6G and except for the base I'd be hard pressed to tell the difference, except for the box on top of the cathode. Wasn't the 807 used in really early designs before 6BG6's were available? I made a socket adaptor and have actually put an 807 into a socket wanting a 6BG6 in my first Admiral. This was early on in my collecting and I had no stock of 6BG6's. It worked but the 807 didn't seem to have as much gain.

Rob

Rob,

I see the 6BG6 is still being made in Russia. Is this due to tube audio demand?