CQ was running "sliding bias" articles controlled by the audio starting with 304TL's in the 50's iffn I remember. Dont think it really caught on. Ive been running amps such as a Clipperton L biased well into Class B AM in order to improve efficiency. Looks good on the SA and the anodes show color only on voice peaks while the transformer is not running hot at ~1200W PEP, no processing tried.
