[462ron]

I think there were some manufacturers that took advantage of the fact that the average consumer equates number of tubes with quality and designed some sets  with an extra tube or two that really had no affect on performance. Such as I’ve seen sets that had a separate 2nd detector tube and separate 1st audio amp. Most use those two functions in one tube so in the case of the set using 2 tubes, what extra performance did it gain other than inflating the tube count? I can’t remember the model or brand now, but years ago I remember seeing a set that used an extra tube only for its filament and nothing else, again it’s just for bragging rights!

Ron