Op, I understand exactly where you are on this. I invested in some really nice tubes for my Freya + and enjoyed it for almost two years. I felt like it was the weak link and that I wasn’t hearing everything my magnepans could give me.
After doing some homework and patiently waiting for the right unit to come along I found a well kept Ear Yoshino 868 that was priced well. The seller was a perfect gentleman and I could not be happier. It was known to pair well with my cubed series amplifier.
Different tubes, it came with 6922 Matsushita NOS & and the upgraded SR fuse. Yes the price of this unit new is 8x the Freya but if you asked me what improved, my answer would be simple. Everything. Cheers.