Northern Electric R221-DX Tube Info?
 

Does anyone have a datasheet or tube information on a Northern
Electric R221-DX Tube? This doesn't appear in any of the usual (RCA)
tube manuals. This tube appears was manufactured in Canada in the mid
1920s.

Charles...

Northern Electric R221-DX Tube Info?
 

I Googled the number and came up with a page in Japanese, which is
translated he

http://translate.google.com/translate?hl=en&sl=ja&u=http://homepage.mac.com/ryomasuda/VT/num/221/index.html

It's a type 201 variant. Click on the "201C" link for a chart.

Dale

Northern Electric R221-DX Tube Info?
 

Thanks. That is what I thought as they were found in an AK20 that had
one 201a in it along with these R221's. Physically the R221's are
different looking than the 01a's as they have a double filament like a
071a has. The filaments also burn much redder than the 01a filaments.

Northern Electric R221-DX Tube Info?
 

On Sun, 8 Jun 2008 12:21:03 -0700 (PDT), VA3NGC
wrote:

Thanks. That is what I thought as they were found in an AK20 that had
one 201a in it along with these R221's. Physically the R221's are
different looking than the 01a's as they have a double filament like a
071a has. The filaments also burn much redder than the 01a filaments.

If they were mine, and the AK20 was used very much, I'd swap them out
for regular 201A's. I bet their 0.6A filament's life is a lot shorter
than the regular .25A ones...

But what do I know? :)

Dale

Northern Electric R221-DX Tube Info?
 

On Sun, 08 Jun 2008 16:37:50 -0700, I wrote:

... I bet their 0.6A filament's life is a lot shorter
than the regular .25A ones...

Err, I meant to type "0.06A".

Dale

Northern Electric R221-DX Tube Info?
 

On Jun 8, 9:48*pm, Dale Carlson wrote:
On Sun, 08 Jun 2008 16:37:50 -0700, I wrote:
... I bet their 0.6A filament's life is a lot shorter
than the regular .25A ones...

Err, I meant to type "0.06A".

Dale

Doesn't that have something to do with older tubes being 'bright
emitters'?

Later, thoriated tungsten cathodes were introduced that could produce
sufficient electrons with lower cathode heater current?

Northern Electric R221-DX Tube Info?
 

On Jun 14, 11:52*pm, Ron in Radio Heaven
wrote:
terryS wrote:
Doesn't that have something to do with older tubes being 'bright
emitters'?

No, bright emitters were 1 amp filament tubes.
It took a good battery to run a set full of those.

Ron W4RON

Thanks Ron. Info appreciated. terryS