Hi,
I’m in the middle of building a ZKIT1 and also trying to really understand what’s going on in the circuit as I go.

Looking at the ZKIT1 schematic (Last Rev 8 - 2025)
I noticed the 0.1 µF cap in the output stage is shown between pin 1 and pin 3 of the output tube socket.

On the ZKIT1 PCB though, that same cap is connected between pin 6 (G2) and pin 3 (cathode), which makes sense for the 6P15P-EV.

Am I right in thinking the pin-1 reference in the schematic is just a holdover from earlier point-to-point builds where pin 1 was used as a tie point, and that electrically it’s always meant to be G2 to cathode, as the PCB shows?

Just checking so I’m understanding things correctly — part of the fun of this kit for me is learning why things are done, not just where to solder them 🙂

Thanks,
/Mårten

Hi MM,
Yes thanks for answering, did some reading up to and the 6P15P aka SV83 tubes do seems to have pin 1 and 6 internally connected
eg. sv83-sed1997.pdf
So from that point connecting the 0.1 µF cap to either pin 1 or 6 does not matter.

Just need to read up on any compatibility issues if swapping in an EL84, but think Steve have already thought of that..

Happy new years