I'm building an F5. In the build guide by 6L6, the resistor across the input, R2, is 47.5K. In NP's circuit on his Operation and Service Manual its R10 and 100K. I don't happen to have either resistor but I do have a 33K. Any problem with that? I don't want to order just a couple of resistors and spend $8 for shipping since I have all the other parts.
I think 33K is fine.
Incidentally, the current schematics as shown in page 2 of the F5T article (and corresponds to the current version of the store PCB) shows R2 at 47.5K: https://firstwatt.com/pdf/art_f5_turbo.pdf
Edit: Found this older thread: https://www.diyaudio.com/community/threads/f5-input-impedance.347530/
Incidentally, the current schematics as shown in page 2 of the F5T article (and corresponds to the current version of the store PCB) shows R2 at 47.5K: https://firstwatt.com/pdf/art_f5_turbo.pdf
Edit: Found this older thread: https://www.diyaudio.com/community/threads/f5-input-impedance.347530/