@oceanica I do not set out to be awkward with my release of information, it is just the outcome of others who chose to confide in me, individuals who are forum active themselves and do not share publicly the info they share with me. It is my being respectful, that is the reason why I do not reveal every morsel.
What I will state, as I have on other occasions is as follows:
My most impressive experiences of Input Valves has come from the a friend who loans Valves from their two generation collection of Valves.
When a Valve is loaned, it will be a carefully thought out affair, firstly there will be the need to have a reliable circuit. My friend is expectant of being informed if anything has been detected that could be a concern for a Valve in the circuit.
A device does not get a premium loan valve unless it has had a longish period of regular use to enable the reports to be supplied that are with an accuracy.
What follows, is on the odd occasion, is the offer to introduce Valves to the device in use, usually approx' £1000 - £2000 worth of Valves will be loaned ranging from the 50's era to the 70's era. My friend does not feel 80's and onwards Valves have the qualities that set them apart from earlier models. That does not mean they are not interested in modern Valves, they are and the individual has used modern valves in their owned Power Amps. My E Linlai 6SN7's will be loaned to my friend for a full evaluation.
When the Valves are being rolled, the typical rolled Valves are of a quality, my friend believes are repeatable from careful purchases, there is yet to be one session that enables all loaned Valves to be demo'd, but there is usually plenty learned about how certain Valves structure the End Sound. If a round two is required, it will be arranged for a different date.
There are also within the Loaned Valves one or two sets of Valves that are the creme de la creme, the very best selected from a substantial amount of Valves undergone investigation from a long-term commitment to the avocation of collecting Valves. Valve Models from a Vintage production era, measured and rolled to select the very best of the best? Who has had such an opportunity, and who would be so generous with such a selected Valve.
I can only say, it is not until the specially selected Valves are used, where such Valves are at or above factory spec'. Where each Valve is almost identical in measurement on each Valve Half and between Valves, with other measurements that concern Valves being at their optimum, does the True Influence a Valve can have on a circuit is discovered, nothing before has the same capability to impress, and all extremely positive impression from before seems poor in comparison.
Once experienced the want to maintain is quite something, but the reality is, it is not attainable, in the modern world, it is the odds of a lottery win equivalent.
I am blessed that on the odd occasion, I am able to be introduced to End Sound that is extremely special, and I am given clear cut guidance of how to take a few rungs up the ladder to create a sensory experience that will be a reasonable mimic.
I fully understand why these very careful selected Valves are not in Permanent use, they are solely reserved as a reference, to learn how close other selections from the same era of production get towards them.
I recently missed a Demo' of a new Phon' in use by a member of my local HiFi Group which is shown in the Link.
https://the-ear.net/review-hardware/zinamp-phono-stage-vinyl-and-valves/
Loaned Valves were used on the day, and follow up reports were mixed on the influence of a Valve and Impression made, I feel confident the loaned Valves will be nice Spec' Valves, near factory spec and quite closely matched on both Valve Halves and between Valves.
This model was far to short-term in use to receive the creme de la creme Valves, later down the line, if these do become a loan, all discussion will be over, JAWS will be agape and that wonderment smile will be on every face receiving a demo'.
It is beyond my capability to suggest I can assist in an individual repeating such an experience.
With the present Valve Market, I am keen to be the one to encourage another to keep monies away from some who will be encountered.
The E Linlai is a Valve, I hope proves itself as reasonable substitute to a few models of Vintage Valves, which is a work in progress, and will most likely be decided by the individual who has forgot more about Valves than a collective education on a forum.
I can become a Valve Specialist in a short period of time, I can become familiar with production era's for multiple brands, I can inform on how to authenticate a Valve, I can pass on factory spec's for such Valves, I can inform on how to select a substitute Valve. All the info referred to is reasonably easy to discover and have at hand for guidance for oneself or pass on to another.
What the stated info does not do, is inform on how such a model of Valve is able to influence a circuit and impact on a End Sound, that one takes hands on experience of the Valves. In this field I am not able to educate, I only have my experiences had, which are kept as a personal information.