I am without a recollection of Brimar Valves used in a line up when Valve Rolling and making selections for a Phonostage and DAC, as well as Input tubes for a Power Amp where the power amp's design is using a half valve only for the Input Tubes.
I am convinced there is nothing extra to be discovered with the Phon' and DAC, but do believe there is still synergy to be discovered with the upstream Input Valves on the Power Amp, which has resulted in Valve Rolling sessions over a few years.
Up until late 2025, I was confident the KR VT231 Black Glass was the most attractive I could have in use. During a new arranged Valve Rolling session in late 2025, I was introduced to vintage 6SN7's that I was not familiar with and compared these to Valves I was very familiar with. The result being all of my owned Valves were shown to not be the best interface, and a new, improved synergy was discovered.
The Valves that superseded the KR's and proven able to produce this new improvement to the system's end sound are a RCA model from the 1950's and a Brimar model from the early 60's. Subsequently, the RCA's are purchased and are a second-best option. The Brimar's are the better option, but are very expensive and not yet found at an asking price I want to pay.
With new speakers added to the system in very early 2026, the revisit to the Valves will once more occur in 2026. There are also newly purchased Linlai Elites in 2026 to add to the 6SN7 lineup. Outcomes of comparisons might once more take a new direction with the new speakers in use.