Circlotron Enhancements
    Having covered some of the how and why of the Circlotron circuit, let us move on to how to improve the circuit.
     One of the biggest mistakes that tube circuit  designers can make is to confine their research to just tube amplifiers. New and fruitful insights await those who broaden their search to include industrial and test equipment tube designs. This also goes for what has and is being done with solid-state equipment. For example, I have been researching the old Quad current-dumper amplifier: a small high-quality Class A amplifier riding shotgun over an efficient, dirty Class B amplifier. Whatever you may think about that particular amplifier, you must admit that he design idea was fascinating. Moreover, this topology could be transported to the tube realm with some adjustments, one 2A3 and four 6550s.
   Another example of fruitful crosspollination between solid-state and tube is the solid-state output stage topology that uses a pair of opposite polarity devices in a compound feedback arrangement: the complementary compound emitter follower, i.e. CCEF. The first half consists of a fast, high-quality, low current transistor or MOSFET acting as an emitter follower and driver stage for a beefy high-wattage transistor or MOSFET. The two work as one high-quality, high-wattage compound device because of the short, fast feedback loop this topology creates. This circuit works best when run in Class A mode and makes for a quite decent solid-state power amplifier.