Hi all!
I found a rather promising tube the other day.
It seems to be either an equivalent (@9V) or a close analogue of the respected and well-deserved 12GN7A.
Has anyone had experience with it?
9KX6:
Plate dissipation max - 11.5W
Transconductance - 36,000
Plate resistance - 50,000
I found a rather promising tube the other day.
It seems to be either an equivalent (@9V) or a close analogue of the respected and well-deserved 12GN7A.
Has anyone had experience with it?
9KX6:
Plate dissipation max - 11.5W
Transconductance - 36,000
Plate resistance - 50,000
Well spotted! 👍Yep, it's the 12GN7A with an 8.7V heater with no centre-tap on the heater winding. Along with the 9KX6, Sylvania also produced the closely related 9AL6, which was an 8.7V heater version of the 12HL7 (Pd max 10W, gm 21,000, rp 55000). I have used both the 12GN7A and 12HL7 with good results, as have many others on this forum, and would expect the same good performance from the 9KX6 and 9AL6. Let us know how you go!!
The only weird thing that i cant understand for the moment - what is a tube called "7KY6/9KX6" actually?
According to manuals, 7KY6 is 7.3V heater tube.
How does it work?
Yeah, I'm aware of tube "12GN7A/12HG7" - but it has at least the same 12V heater.
According to manuals, 7KY6 is 7.3V heater tube.
How does it work?
Yeah, I'm aware of tube "12GN7A/12HG7" - but it has at least the same 12V heater.
Yeah I noticed a lot of the boxes have dual markings. Not uncommon but I have never seen two different heater voltages.
Not two heater voltages that are that different anyway. And it looks like 7KY6 data sheet shows 30,000 gm, not 36,000. As if 21,000 wasn’t enough. How the hell would they make a 4.5 MHz amplifier stable with that much gain….
The data sheets indicate that electronically the 6KY6, 7KY6, 11HM7 and 12HG7 are very nearly identical (capacitances, transconductance etc etc) but with different heater arrangements.
Electronically, a 9KX6 or 12GN7A is close to but not identical with the members of 6KY6/7KY6/11HM7/12HG7 family.
That said, electronically they are all pretty similar to the extent that, in TV repair land, the 12GN7A was pretty much a direct replacement for the 12HG7 and boxes were marked with both designations ....
Electronically, a 9KX6 or 12GN7A is close to but not identical with the members of 6KY6/7KY6/11HM7/12HG7 family.
That said, electronically they are all pretty similar to the extent that, in TV repair land, the 12GN7A was pretty much a direct replacement for the 12HG7 and boxes were marked with both designations ....
Not uncommon with series-string tubes - what matters is the heater current - small difference in voltage is insignificant as part of entire heater string. 5KD8/6U8 was common, as was 13EM7/15EM7, among others.