The PV12AL is an upgraded version of the PV12L.
This is from the Conrad-Johnson website:
"The PV-12 superseded the PV11. Like its predecessor, it featured zero feedback circuits, and passive equalization in the phono stage. For the PV12, critical plate resistors are a special laser-trimmed metal foil type chosen for their extremely low noise and low inductance. The balance control is an eleven-step switch incorporating discrete resistors.
The PV-12L is a line stage version of the PV-12 without the phono section. The PV-12A/AL upgrade consisted of upgrading the volume control circuit and incorporationg a new biasing circuit for the input amplifier of the line stage. This new arrangement eliminates local feedback from the line stage voltage amplifier."
The PV12 and 12A have a phono stage and line stage, the PV12L and 12AL are line stage only with no phono stage.
Hope this helps.
