The old standard was 220K with a .1uf. It still works and can be used with no problems. However he cautioned against going higher due to possible LF oscillations. The time constant is a little larger but you can't hear the difference unless you get LF Oscillations. Dave did some calculations a few years ago and found .72uf or .73uf (Those numbers stuck for some reason but I can't remember which one. However it's irrelevant to this purpose as no one makes a cap that size.) was the ideal. But due to lack of a cap that size he recommended a 0.68uf or .082uf as the next best value.(At the time both values were fairly new and not widely available and hard to find). As .068uf is closer than .082uf it's a better value to use, although the .082 is good too. No audible difference is discerned, but it will show up on a scope that is sensitive enough.
I don't remember the exact calculation but the resistance multiplied by the cap value sounds like it might be the correct . Lets see if this works.
330K x .047 = 15510 Original Factory Values.
220K x .071= 15620 Ideal replacement but not feasible due to lack of cap value.
220K x .068 = 14960 Closest replacement to the 330K/.047uf. Parts available.
220K x .082 = 18040 Last two values are useable if .068uf aren't available.
220K x .1uf = 22000
I don't remember the exact calculation but the resistance multiplied by the cap value sounds like it might be the correct . Lets see if this works.
330K x .047 = 15510 Original Factory Values.
220K x .071= 15620 Ideal replacement but not feasible due to lack of cap value.
220K x .068 = 14960 Closest replacement to the 330K/.047uf. Parts available.
220K x .082 = 18040 Last two values are useable if .068uf aren't available.
220K x .1uf = 22000