I haven't seen this kind of arrangement anywhere except with the Alan Kraus design and the Leach Superamp and those two were using older and slower power transistors.

I've read critical comments about power cascades or totem pole arrangement output stages and I'm not so sure what to do with this information. This could explain why even minor changes in the VAS stage make a mess of everything. The circuit appears to be very sensitive to changes in R1 and there is significant gain above 1MHz or so. I've attached a stripped-down schematic which shows just the output stage with 'ideal' VAS and bias generator. I've run many simulations over the past weeks and I think the instability issues can be really narrowed down to the output stage itself. However the problem with this type of design is that I cannot get it running stable.

I did like the output stage however and I tried designing something similar using more modern plastic-cased transistors. In any case, I have a pdf available if anyone is interested. I don't think it is worth the effort to build this design as both input stage and VAS are very simple and I assume that the performance won't be very good. Czech magazine 'amatorske radio' published this design back in 2000. I thought the next best thing would be to connect the output transistors in series just like in the 'low-end zesilovac 1kW' from Alan Kraus. There are complementary 350V bipolar transistors available from On-Semi, but the problem with these is that they're almost useless at these voltages due to SOAR limitations. Unfortunately there are no additional secondary taps available and thus the amplifier will have to be class B with no sliding rails. The story is as follows: I managed to get an excellent deal on two used 1600va 2x115V secondary toroidal transformers and right now I'm contemplating building a very large amplifier around these two. I hope I did get the name of the topology right.

Totem pole output what is