Patent drawing - A.D.Blumlein US patent 2185367 - long-tailed pair Public domain image

Long-tailed pair with cathode auto-biasing. Figure 3 from A. D. Blumlein's US Patent 2185367 (British 482740), priority from 1936-07-04. The original was slightly altered - I removed output cathode followers, which are not part of the LTP per se, and moved one of the interstage caps into the cropped area.