6G15 signal question

[Randall]

I don't understand how the clean signal gets thru to the output. I see how it hits the other side of the 7025, but I don't understand how it gets to the output from there. I've seen it explained that it goes thru cathode to mixer out, but I don't understand this. Help?

[Jazz P Bass]

I do believe that you answered your own question.
The dry signal comes off of the lower (on the schematic) half of the 7025 dual triode.
The signal is taken off of the cathode.
The circuit is called a 'Cathode Follower'.
The input to output phase remains the same & the output impedance is low, so it can easily drive the next stage.
Here are some links.
Cathode Follower Output Impedance Calculator
The Valve Wizard -Cathode Follower

[Bruce / Mission Amps]

The dry signal bypass all the tube sections except the bottom half of the "voltage divider biased" 7025.
Note the classic "Paul C mod cathode follower" circuit... although many of us think a 4m3 resistor works better on top of a 1M. Not critical here.
Anyhow, since the signal out of the cathode follows the grid ("in phase") with low impedance and only very slightly attenuated, the dry signal is mixed into the reverberated signal via the, well, wet-dry "mixer" pot, wired as a balancing circuit....
Gents, this is an extremely simple circuit and every vacuum tube home builder needs to build one to see how elegant and easy this reverb circuit is to make!!