Subbing the filaments with bulbs is a tricky proposition. They have to have the same current rating as the tube or the string voltage will be out of balance. 
Ever see that old trick electricity question about to bulbs in series? One is a 40 watt and the other is a 100 watt. which will be brighter?

On Tuesday, September 16, 2025 at 06:48:02 AM EDT, Christopher Bowne <[email protected]> wrote:


If you have 572Bs they are plug and play subs for 811s - just have a hjgher plate dissipation rating.  I’ve been running a pair of them in my ART-13, removed from my OOC SB-200 amp since I lost an 811 snd didn’t have a spare at the time.

73 de Chris AJ1G

Sent from my iPhone

On Sep 15, 2025, at 22:51, B. Smith via MRCA <[email protected]> wrote:


I was running short of 811s and operate primarily CW.
Subbed light bulbs for the tubes to keep the 813 lit.
k4che
<k4chekeyer.gif>


http://k4che.com/ART-13%20WO%20811s/ART-13%20Without%20811%27s.htm

<bulb sub.JPG>

<bulb sub.JPG>
______________________________________________________________

MRCA mailing list
Home: http://mailman.qth.net/mailman/listinfo/mrca
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
______________________________________________________________
MRCA mailing list
Home: http://mailman.qth.net/mailman/listinfo/mrca
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html