The question was: how to do it with 803's The source listed is the Bill Orr Handbook. He calls all of the circuits Zero Bias Tetrode Modulators. Even the 807 and 813 in TRIODE connection is shown with the beam forming plates grounded. The circuit is about zero bias, and no screen supply. The 803's are shown since they were one very plentiful and cheap. My understanding of the suppressor bias is that it allows the plate voltage to swing down to it and increases both headroom ( work space) and increases efficiency. 510 watts output with clean audio is not bad for zero bias and no screen supply, The suppressor voltage is actually the voltage used on the speech amp plates which is says can be 6B4's or most any 8 watt speech amp. He does say these tube require more drive than 813's but since the then price for a new one was four dollars a tad more drive make little difference. In W6SAI's 14th edition Radio Handbook page 595, chapter 27-3. Seybold's patent no. 2,494,3176 explains the use of beam tetrodes in TRIODE connection to use no bias and no screen supply. The drive is applied to the screens and a resistor to the control grid. The 15th Edition says the grid resistors are not needed for the 803 or 813 tubes.. Hope this helps..
Mike
