Looked at more of the BBI video.? He has done the fil choke wrong.? His method will saturate the type 43 cores.? ( no bifilar action).? ?The reason 2 x wires are passed through the core, or 2 x wires used on a rod is, that the current flows up one wire, through the cathode, then back down the other wire.? ?The 2 x magnetic fields cancel each other out..... resulting in zero? ferrite saturation.?
Also? saw where they modified the oem socket, and removed the screen bypass caps....which were originally above the chassis.? ? He has made of curved copper straps, so the former grid finger stock is bonded to the chassis.? ?Grid fingerstock sits on top of the copper straps.? Screen grid is also bonded to the chassis.?
IOW:? he's gonna try and run it as a high mu triode, with both the 1750 watt? rated screen grid.... and the 500 watt? rated? control grid, both bonded to the chassis........ no different than a 4-400? or? 4-1000? with both grids bonded to the chassis.? ?Problem is, the control grid in that config dissipates most of the power, with very little diss on the screen.? ?That's why the high mu triode version (3-500Z? / 3-1000Z) has double the grid diss...vs the tetrode.?
A 3x10/15/20? ?high mu triode has 500 watts of grid diss.? ? That's for? 15/25/30 kw pep out.? ?And typ 750 / 1250 / 1700 watts pep drive.?
Now? BBI wants to stuff 20 kw of drive into a tube that only has 500 watts of grid diss....... well good luck with that.? ?It requires a 3-6 kw? grid.?
Apparently, they are gonna? run the B+? supply on 240 vac? single phase.? ?Doable, but will require a 250 kva ccs xfmr out in the street, pad mounted....and a 1000++ amp rated drop wire.??
They are gonna find? all? this out the hard way.?
