As the owner of many Valiants and Rangers, I can assure you 100% any stuff about certain 6146's not neutralizing or not working is nonsense.
The ONLY time a 6146 will not sub is if the tube you bought is defective, or the equipment you are plugging it into is hypersensitive to impedances of the tube at very high frequencies. If you have unstable gear, like some Collins rigs that wrap feedback around multiple stages, or certain VHF transmitters, you might have to be brand specific.
My Ranger II's are just fine, even on six meters, as are my other Valiants and Rangers across HF all the way to ten meters with 6146B's or W's or any other flavor. I have never once had an issue.
I only had one Ranger and one Valiant so can't speak about those, much. But the KWM-2 seemed picky.
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