A working amplifier Full schematics of the amplifier, power supplies, and protective circuits appear in Figures 1 and 2 . Should two relays be used, the output changeover relay should be the faster of the two. Ideally, the output relay should be a vacuum type, because its operation times are in the millisecond range. This has the effect of stiffening the supply. It's an excellent application of a method that was used in the past for high-voltage plate supplies, except this one is for a screen supply.
Linear amplifiers do require steady screen voltages.
All in all, the 4CX1600B is a very good tube, especially for this service and for other classes, too. It is linear, stable, easily tamed from parasitics, and is trouble-free. It is a delight to operate. He is one of the most knowledgeable engineers I've ever encountered. His frequent sessions have been of inestimable value not only to me, but to many silent listeners as well.