TR/JM "Wonderland" Mixer V-4 - Commentary

[W5FH]

Hello-
In reference to the attached schematic I wanted to ask others for any commentary in regards to the mixer tube V-4. I am curious about the configuration of the components R-42, R-27 and C-22 in the plate circuits of V-4A,B. It appears as a form of "common anode mixer" to me since there is a DC connection between the plate circuits through R-42 and R-27. The plate current draw of one triode can affect the other to a small degree. There would be a difference be if there were coupling capacitors between the plate load resistors (R-25, R-40) and mixer resistors (R-42, R-27). It appears to me this choice was deliberately made in the design of the stage, in other words there must be a benefit in the operation of this stage (slight second harmonics) as a common anode mixer as opposed to using coupling capacitors to DC isolate the plate circuits of each triode. Just curious about this as I have worked some with the common anode mixer in other designs (such as Astroverb).
Just trying to learn more!
Thanks all

[sluckey]

Nothing special. Just a different way to mix two signals. I guess the advantage is saving a couple caps. No need to be concerned about the effects of one tube on the other. Afterall, the goal is to combine the two signals. Plenty of amps use direct plate coupling to feed the mixing resistors. Here are a couple examples just off the top of my head. Look around and you will find lots of other examples...

https://el34world.com/charts/Schematics ... _schem.pdf
https://el34world.com/charts/Schematics ... e_m10a.pdf

Both these examples use direct coupled mixing resistors to mix the two channels together just prior to the PI.