The Pre Amp' which is correct when referred to as commission built, has a Prototype SS Section already in use, which offered a Complex Internal Design for Earth Lifting, as well as a SS only Circuit which is as Transparent as can be.
When used with Valves the designer informs that it is the Valves that are only being heard, the pre is not an influence.
The Prototype Pre' was also produced with the option to add gain up to 13dB.
I have used all the options in my system and done assessments with other friends sharing a audio interest. The P'type Pre' has also been inserted into other systems.
It is so so revealing it catches one out, especially when not familiar.
So far it can be safely stated, good quality recordings are not wanted to be listened to without the pre in use once experienced.
The Valves on the final version will produce a Single Ended Pre Amp' that is solely to add two versions colour that can be tweaked to control the influences of each, as an alternative to unadulterated transparency.
I was offered one Valve as an option that would have been very closely matching the Transparency of the SS, but that was not my objective.
Different and discernible influences were to be the goal, Tube Rolling is a favoured side hobby in Audio Equipment experiences. Additionally, I do loan owned equipment to other non owned systems on a regular basis to help others find their experiencing a produced end sound that is created to meet with their preference. The Amp design and Tube Rolling Options will assist with others who are being investigative.