Drake made a 2LF converter especially for the 2A and 2B to receive 160M and
even the AM standard broadcast band.  The 2LF is rare but they show up for
sale every now and then.  I have one. It installs inside the receiver and
comes with provisions to plug in crystals that give 600 KHz of bandwidth per
crystal.  As I remember the 2LF can be used to receive 600 KHz slices from
500 KHz to 2 MHz and perhaps even higher. -AD4U

Another simple solid state converter is the Drake 2LF which provided VLF, MW,
or 160 meter coverage depending upon the crystal installed.  It is a simple
mixer/oscillator system without a tuned front end.  One came with my 2-B
receiver and I should also have the information for it.  It is designed to
convert up to 10 meters but it would be easy to make slight changes when you
build your own so that the output is within the frequency range of your
receiver. - rsingl