what is your preference: Keying the modulator bias with the plates or having the bias always on.
Hi Big G -
Broadcash style layout... 833As in parallel modulated by a pair... nice.
Bias: There's many ways to key the rig. For many years I have placed a 50K resistor in the fil CT of the final and the modulator and keyed these resistors on and off using separate contacts. (PTT) This completely cuts off each stage.
I also break the audio signal going into the modulator just before unkey to eliminate pops and noises.
In addition, though not required, I key the HV power supply on and off using a step start that uses a 10 ohm 200 watt resistor in the HV AC primary. I just like to have the HV off to save bleeder power and for more safety.
All of this needs to be sequenced in the proper order with delays. The RF drive and antenna relay may need sequencing too, of course.
BTW, if you get any EXCESSIVE mod transformer or Heising reactor spark gap arcing during key or unkey, I solved it using a 200W 5K power resistor across the gaps that gets opened and closed to suck down the stray/unused RF and magnetic audio power during unkey. This requires a HV or vacuum relay in series with the 5K. The description is in my 4-1000A project thread if interested. Works like a charm to completely snuff any PTT-related arcs/sparks.
Maybe your appearance back on with the new rig will get me motivated to flip the switches on too... :-)
T