An article was published in the August 1990 issue of a now defunct magazine called AUDIO, in which the Compact 100 was reviewed and extensive specifics and measurements were reported.
In that article, the writer notes the "relatively low plate current per output tube, 26 to 32 mA, that is set at the factory."
Also, the writer continues, "The Compact 100 has a single control to adjust overall bias, ... This makes it possible to run up the bias by turning one control, instead of commutating among the four individual bias controls ..."
So, there are five bias pots: one master and one for each of four tubes. Adjust the bias of each tube and, then, you can raise of lower overall bias using the master control.
