Using the Pentode/Triode Tube as the Amplifier/Phase Splitter.
Valve Analogue, Tube Analog, Guitars and Stuff: JCA20H with EL84 Triode / Pentode Switch and schematic circuit diagram.
Pentode/triode switch question | diyAudio
Tube Amplifiers Explained, Part 9: Screen Voltage and Ultralinear Mode
Pentode Triode Switch - Music Electronics Forum
A Single Ended Tube Amp for the masses! - Part II
ST-120 Triode/Pentode Switch
VTA Tube Amp Kits - All the Dynaco VTA amps may be run in either ultralinear mode or triode mode. They all have a switch that allows going from one mode to
You Can DIY! Meet the Pentriode | audioXpress
pentode/triode switch - Music Electronics Forum
Using A Pentode As A Triode - Quantumnet
Triode/pentode switching system for the Dynaco ST-70