Tube sub for a Globe King

[KE5YTV]

  I've been to told that the RCA 8005 tube is a drop in replacement for the V70D's in my Globe King 400B. Can anyone verify this? Thanks guys.


Mike
KE5YTV

[N2DTS]

Different filament voltage.
7.5 volts for the V70D and 10 volts for the 8005's.
Plate dis is the same.
812a's are 20 watts less plate dis and 6.3 volts.

WA3JVJ ran 8005's in his gk400.
Not sure if he did anything with the voltage.

Brett
 

[WD5JKO]

I'm not sure of the filament amps required for the V70D, but the 808 is also 7.5v (4amps each), and might adapt well to the old GK. The grid of the 808 does not go to the base, kind of like a 100th.

Jim
Wd5JKO

[w0ene]

You might consider 5514s.  Their fil voltage is 7.5v at 3 amp each and the V70D is 7.5 volts at
3.25 amp.  Also the GK-400 plate supply is around 1350 or 1400 volts so that should be ok too. 
You may have to adjust the bias a little and the 5514s have a little less plate dissipation.  The
only real problem might be the required drive is much higher on most of the substitute tubes then
the V70Ds.  My GK-400 came with pounds of rust and a gutted RF deck.  Nothing left but the
front panel and 2 bad tripplett meters.  So I reused the front panel and built a homebrew 813 rig.
Had to start from bare metal on all the chassis and the cabinet.  Let us know what you decide and
how it worked out.

73, John - W0ENE

[KE5YTV]

   John, I found a V70D today. Since the GK also uses a pair of 5514's, I think I'll lay in a couple of spares. It sounds like they would be a good back up plan.




Mike
KE5YTV

[K8WBL]

I have seen folks also sub in 811A's, just lower the filament voltage a bit..the GK500 uses 811A's... but I think the 5514's have stouter plates, somewhere I read that they are graphite, but don't know about that.  I love the audio on my Globe Queen 400B.

73, Tim K8WBL

[N2DTS]

?
I thought the V70d's were in the rf deck.
811a's in the modulators.

Brett

[Detroit47]

I've put 811's in the RF deck before and they worked fine. I changed the filament transformer as I recall. I did this for a fellow about five years ago it's still running.
73 N8QPC

[K8WBL]

I have talked to several guys who had put the 811A's in the RF deck... a little less output,,not much less.  The V-70-D's are 85 watt plate diss. and the 811A's are 65 watts plate diss.   Always wanted to try the 572B's in place of the V-70-D ... I own a GK400B (in daily use) and GK400C (under restoration) and a GK500A .. (also under restoration)  really reall nice transmitters with personality and easy to work on for a person with my limited skills...hi hi


73, Tim K8WBL