ULTRALINEAR PUSH-PULL LAMP CASCADE WITH CONTROL ON SECOND NET AND METHOD OF ITS ADJUSTMENT Russian patent published in 2018 - IPC H03F1/00 

FIELD: electricity.

SUBSTANCE: cascade consists of a pair of tetrode or pentodes lamps VL1, VL2, included in the scheme of Fig. 1, Tr1 transformer with connected to the secondary winding L3 load Zn and specified voltage ratio provides a specific position of load line on static characteristics of push-pull cascade lamps, wherein the first (control) lamp nets are grounded, which extends the bandwidth of the amplifier at the top of the audio range, and the second (display) nets are more linear controlled. In the second (display) lamp nets additional ultralinear winding L4, L5, are included, which further increases the linearity of cascade control and reduces the level of harmonic and intermodulation distortion. Adjustment of cascade comes down to installing 2 net capacity (screen), in accordance with the timetable of anode current dependency on the potential of second (screen) net, within 20-30% for class AB, B, and middle of the linear part of the specifications for class A. Offset in the first (control) lamps net of cascade is set by any known way, but maximum linearity of cascade is achieved by specifying an offset by 1 (control) net by current sources in cathodes, shunted capacitors to fix degeneration feedback.

EFFECT: increase the linearity of push-pull lamp cascade with a reduction in the level of nonlinear distortion.

2 cl, 1 dwg