Bottom line is simple, unmodified rice box audio is tough.
They are designed to lop off everything below 300Hz and above 3000Hz., broadly speaking. Without mods most commercial solid state SSB intended radios do not sound very good. Mine included (a slightly modified TS-440s)!
Since you have to set ur carrier to about 20-25% of rated CW carrier level, that puts the typical rice box down into the 10-25w carrier level, very weak. If you are going to try to do that you definitely need a
good antenna to have a prayer of being heard.
The "standard" for AM QSOs "back in the day" was a pair of 6146s modulated fully, which translates to a >100watt carrier with 200-400watts PEP after modulation. Consider that a Ranger or a ricebox run into a pair of 3-500s (in a linear) will give you only slightly more output than that (maybe), and you start to see the scope and nature of the issue?
That was for your everyday signal - the same as today's Kenwood or Icom, Yaseu SSB signal. The "big boys" - they guys who got heard were running 400-1000watt plate dissapation tubes that were
then plate modulated! Same thing today.
Bottom line is that although it doesn't seem like it, an old vintage transmitter does more than seems obvious at first look on AM!
Consider maximizing ur antenna and maybe finding a vintage bit of transmitter or some other similar output level transmitter?
Personally, I think a good part of the fun in AM
is the really kewl gear.
That and keeping the shack warm in the cooler months.
_-_-bear