English Channel schematic oddity !?

[stm]

Looking at the English Channel schem at ROG I noticed at the fourth FET there is a series 1M res+10nF cap to ground from the source resistors (1k2 & 4k7).

I've been thinking this is either useless or there is a typo in the 1M resistor value, since 1M in parallel to 4k7 is almost 4k7 no matter the cap value. :?

For this to make sense, I would expect this 1M resistor be as low as 10k or even less.

Does any one have an idea on this?
Current schem is v1.1.  Was there a change on this area from v1.0?

Best regards!

[petemoore]

Looks like theres a big resistor there letting a small amound of whatever that 10n lets through to the source of J4...make that ground point liftable and see what differences and explainations you can find.
 The build should be fine as shown.

[stm]

I simulated the fourth stage of the circuit, and verified it is irrelevant if the 1M+10n are there or not, which confirms my thoughts.

Also, I went to the source.  Looking at a VOX AC-30 schem from 1990, I see said resistor/cap combination set bias for a differential valve amplifier.  Since the second valve is non existent on ROG's implementation, and these components do not affect sound as they are, I'm pretty sure they can be removed without affecting tone (IMHO).