Curious … cathodyne question

[Diverted]

Hi all,

Building a Princeton Reverb without tremolo. So V4A is unused. Other half is the cathodyne phase inverter.
What would happen if I strapped the two triodes together and halved the cathode resistor? Not brave enough to try since it doesn’t take much to saturate the PI I’m guessing it’ll not be good.

{edit: fix typo in title --PRR}

[sluckey]

I would just leave the unused triode unconnected. That's what Hoffman did.

[HotBluePlates]

... cathodyne phase inverter.
What would happen if I strapped the two triodes together and halved the cathode resistor? ....

Nothing useful because the cathodyne phase inverter offers no gain.

If you wanted to do something useful with the extra triode you could use a long-tail inverter rather than cathodyne.  The problem with this approach is you would then need to move the injection point for the negative feedback from "the stage before the inverter" to "underneath the inverter."  And if you already have something like an eyelet or turret board this means re-thinking the layout & connections for that.

Yeah, you prolly just want to leave it sitting unused.

[Diverted]

That's what I was thinking. Just curious, thanks for the insight.

[tubeswell]

If you convert the PI to a Long Tail Pair, it won’t be a Princeton Reverb any more - more like a Deluxe Reverb