TubeCad simulation driverstage 5687 capacitor
coupled hybrid amplifier

Tube Cad simulation :

This 5687 simulation is using one triode section. Load resistance is 15K.
Amplifier will work just fine with one triode section. A 2uF coupling capacitor will give a 4.8 Hz cut off frequency.

Another interesting schematic is shown down here, it's a Grounded Cathode Amplifier using a Cathode follower. Output impedance is as low as 109 Ohm.