Not sure of value but grid Steve.
charles
The 0,1uf just seemed small unless it was either for bypass, or the grid resistor is quite large.
Otherwise it seems to be working as a high pass filter, ridding of very low frequency garbage.
cheers and all the best.
steve
+1 on what Steve said. Another place I always look is the quality and TCR of the cathode and plate resistors. Low noise (TCR) resistors in these positions generally produce better SQ. That is UNLESS they produce the “character” one desires. Audio is sooo complex sometimes
My go to resistors are generally PRP, Takman and Mills for the majority of applications.
For digital I/V and other positions the laser trimmed nude Vishays from Texas Components are my personal faves. They work fabulously in phono stages, too. TCR of 1ppm!