I am designing a mic pre based on three 6AU6 tubes. The first two are
operated as triodes with no NFB with an overall gain setting pot divider
between them and the last is a cathode follower. I have discovered that by
judicious selection of the component values in the CF that the
predominantly 2H distortion of the first two stages can be reduced by a
factor of 10. This effect is not frequency or output level sensitive but
does depend on the setting of the inter stage pot - it works best at
highest overall gain.

I was very surprised to see this effect and wondered if anyone else had come
across it. I seem to remember an article somewhere about a two stage amp
where the second stage adds the same sort of distortion to the inverse of
the waveform and hence reduces overall distortion but I cannot at present
lay my hands on it.

OK, admittedly these are just simulations at present and yes, Patrick, I
have pretty much all the components on hand and I WILL be building it as
soon as possible. It is so intriguing I cannot resist.

Cheers

Ian