The 600 Plus uses the LND 7317 tube. I'm wondering how GQ decided to use the 7317 tube instead of another LND pancake tube. Does it have to do with operating voltage? The 7317 is an excellent, sensitive, tube however.
I also think that the choice of the 7317 is certainly because of its voltage. to have a lower voltage, certainly the gas pressure inside had to be lowered (this is pure speculation, if anyone can confirm or deny).
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