Specifications

The yellow line connecting at the top of the network comes from the HV power supply. The
bottom of the network connects to the base of the plate choke. The top end of the plate
choke connects to the tube side of the plate DC decoupling capacitor bracket marked letter
"E".
At this point you will notice that the plate decoupling caps are NOT original, and your right.
The original caps can be seen in Fig.1, letter "D".
My opinion on the use of "disk type" caps in high RF current/ high HV applications is a
cheap and not so reliable method. I opt for heavy epoxy encapsulated "door-knob" type HV
capacitors. I used two 1000pF @ 10kV caps, which required a new mounting bracket, that I
fabricated out of copper plate stock. These copper brackets can carry far more RF current
too. The new design is seen in Fig.2 letter "E".
Under the sockets
Fig.3
Fig.3 shows the under side of the tube sockets, unmodified. You will notice that there is no
filament choke, I'll discuss this in detail later. The letter "C" points out the cathode choke,
which is only a 15µH @ 2A. unit, I removed this choke and replaced it with a choke of my
own design. I used a yellow mix toroid of about 5/8ths inch inside diameter. I wound #24
insulated wire on the core. The final inductance is 100µH. Toroids are self-shielding, so this
should be a very effective RF choke. My reason for doing this mod, is that the original choke
could resonate on certain frequencies in the ham bands, this mod prevents that possibility