1. Parallel-tuned,series-fed configuration:

The diode-clipped parallel-resonance voltage is output to the phones. High-impedance diodes
and phones are required to match the high impedance of the parallel-resonant circuit. This configuration is suitable for reception of distant, weaker stations.
2. Series-tuned, shunt-fed configuration:

The diode-clipped series-resonance current is output to the phones. Low-impedance diodes and phones are required to match the low impedance of the series-resonant circuit. This configuration is suitable for reception of nearby, more powerful stations. 3. Series-tuned, shunt-fed variant:

This is a variant of the above series-tuned, shunt-fed configuration. Using low-impedance diodes and phones, it delivers identical performance.
Very interesting and comprehensive, OM Al.
Many thanks.
73,
Nandu.
Take a look here: http://www.skywaves.ar88.net/xtalset102/xtalset102.htm