Shouldnt be too much trouble to use the EL509 for this.
The filament requirements are the same.
The tube socket would need to be changed to 8pin type.
And need to be aware of the plate voltage limit. The 6kd6 claimed to handle nearly a 1000 volts, but the EL509 says it can only take 700v.
540 watts from a pair of 6KD6's? :blink: That won't cook them,that will cause thermal meltdown! I would think that given the age of that radio the 540 watt rating is INPUT pep rating.Radios and amps of that era always stated power as INPUT to the finals and not as output. BTW I may,just may still have a pair of NOS GE or Sylvania brand 6KD6's still in the boxes kicking around in my stash. I'll have a look-see later tonight when I can actually FIND my tube stash. :headbang
OK I finally got into my tube stash and I have good news and bad news. Unfortunately the bad news is that the 6KD6 boxes contained old used Sylvania tubes in a GE box.What I thought were new 6KD6's were in fact a bunch of 6146B's instead. The boxes are nearly identical in appearance.The good news (for me anyway) is that I found that I have four brand new old stock American made GE brand 6146B's and a pair of NOS American made Westinghouse brand 6146B's as well.Sorry they are NOT for sale. My TS-820S would love them. On the other hand if anyone is looking for some JAN 5933WA's, I have a half dozen here that are all NOS in the original plain white boxes. They are all Phillips brand. The JAN 5933WA is the military version of the 807.
There's a matched pair (new) on eBay:
MATCHED PAIR OF NEW BOXED REALISTIC 6KD6 RF SWEEP TUBES - eBay (item 120339694940 end time Dec-01-08 19:04:06 PST)
Don't know what you're looking to spend. The opening bid is $48 and nobody has bid yet as of this post.