The YC-156 and it's cousin are pretty much, as you stated and heard, 3CX15,000s with a 5Kw anode cooler, AND A SMALLER GRID!!!!!!!!!!!!!!!!!!!!!! Keep that in mind. It's like a 3CX5000, with the grid of an 8877! At half the price of said 8877, though
With almost 4 times the diss
yipee!!!!!!!!
It has a lot of Cout. Keep that in mind.... That being said, I've seen 4 play when the clown was too cheap to buy a 20K tube.
Like ALL indirectly heated cathode tubes, and small grid structure tubes, you HAVE to wait the warm up time, or you will REALLY lose emmisive capabilities fast... IE, you'll trash the tube quick.
Also, you REALLY want a ramp up on the fils. Check out Emtron's filament ramp up circuit... About the only thing I have seen I LIKE they do.... Slowly ramps up fils voltage over time.
You don't really need a parasitic suppressor on the tube... Even on 10 meters... Although having a bit of L in the anode line won't hurt, as I said, the tube has a bit of Cout.
The grid IS WEAK... BUT, if you can keep the CHASSIS cool, you benefit from the heat sink effect, and according to Reid Brandon and a few others, the effective Grid diss can be doubled, give or take a few percent, IF THE CHASSIS OF THE AMPLIFIER CAN BE KEPT SUFFICIENTLY COOL TO KEEP THE GRID COOL!!!!.
You can also blow more air through the tube by building a square air plenum box, instead of using an Eimac type round chimney. People using the 'other' YC156, the 6 Kw version have reported being able to Diss close to 10 Kw.... The anodes are the same, from what I can see.... It's all a matter of getting enough air through the fins of the tubes.
Hope that helps.
--Toll_Free
