[Amps] 6LQ6 6MJ6 Sweep tube conversation

[Gene Bigham]

I would like to comment on my experience with a replacement for the 6LQ6 tube.  It was a 6MJ6 tube that was substantially heavier all the way around.  The glass envelope was 4 times thicker for starters.  The plate cap was not a cap soldered to a thin wire emitting from the top of the tube but an integral molded part of the top of the tube in the form of a ribbon of metal from the plate or anode to the top of the tube and the plate cap molded into the thick glass enclosure.  The plate was heavier metal than any 6LQ6 or 6JE6C that was made.  The 6MJ6 was considered industrial version of 6LQ6 and about 4 times the tube of any 6LQ6 made at the time, circa 1970's, 1980's, early 1990's and RCA's were the best of the 6LQ6's at that time; but the 6MJ6 were better.
I have no idea if 6MJ6's are still available anywhere, I paid twice the price for them when I was using sweep tubes in a rig that had tube finals, and a linear that ran them as well.  They took a tremendous beating that would kill a normal 6LQ6/6JE6C tube.
These tubes were hard to beat, kinda like having a 3-1000z in a 3-500z enclosure but at much lower plate dissipations, say 90 to 100 watts.