Coupling cap spec

[wanders]

What coupling cap capacitance would sound best in a 6SN7 preamp controlling a McIntosh MC-2105 (input impedance of 200k ohms)?

 

[rayma]

What coupling cap capacitance would sound best in a 6SN7 preamp controlling
a McIntosh MC-2105 (input impedance of 200k ohms)?

Ideally it would be a 2Hz pole, so 1 / ( 2 x Pi x 200kOhm x 2Hz ) = 0.4uF

 

[Eli Duttman]

For several reasons, the high pass pole formed by the coupling cap. and the I/P impedance of the power amp should be <= 2 octaves away from the lowest freq. of interest (20 Hz.).

So, the "standard" value needed working into 200 Kohms is 0.22 μF., which yields a F₃ of 3.6 Hz. Now, the debate about dielectric begins.

 

[wanders]

I installed Mundorf Silver Oil 0.22 uf but after some reflection wondered if 0.4 uf would make an audible difference.