G7/analag mic capacitor question -- cap right before plate resistor

[Blue Jinn]

Hi,

I'm currently building a point to point G7 (single sided capsule version) and curious about the 2u2 cap between the 10k resistor and 100k plate resistor. (Similarly the 1uF before the 100k plate resistor in the analag 6AU6 mic.)

Is this additional power supply filtering? I couldn't fit a non-polarized cap in my build so I put in a 2u2/250v electrolytic there. Why would that matter?

Thanks!

 

[volker]

Is this additional power supply filtering?

Yes. Also getting rid of some crap that the cable might have picked up along the way.

I couldn't fit a non-polarized cap in my build so I put in a 2u2/250v electrolytic there. Why would that matter?

Film capacitors have a longer life expectancy and lower ESR. But an electrolytic will be fine as well.