The 1961 Acrosound ST20 pushpull amp was a true double Loftin White. Two DC feedback loops, left and right, functioned almost independently
<a href="//commons.wikimedia.org/w/index.php?title=User:Retired_electrician&amp;action=edit&amp;redlink=1" class="new" title="User:Retired electrician (page does not exist)">Retired electrician</a> based on a 1961 design by Herbert Keroes <a rel="nofollow" class="external autonumber" href="http://lilienthalengineering.com/wp-content/uploads/Acrosound-st-20-DC-coupled.png">[1]</a> which as a pushpull implementation of the 1929 Loftin-White circuit
<span class="int-own-work" lang="en">Own work</span>