He it is again just in case you did not see it.

"Frenchy lots of preamps wil have a final stage which the signal will go through. My EICO has a pair for each channel and then a fifth tube which it all filters through. What it means is that you can have more fun manipulating the tone. I often switch out this fifth tube between a Mullard and a Psvane. I am done rolling for now, so enjoy and hopefully you will find the perfect combo. "