I just don't know... but, isn't interaction between controls what we like about vintage stuff, or is it the only thing we hate about them but we love all the rest? Jus't saying, is such a problem that interaction?
In the other hand, as you seen the compensation with the output impedance, using a dual fader, where one would be used as fader and the other as compensation isn't an option? It would add a little complex in a much 'better' (with less interaction) and clever design I guess.
There are other options in passive eq, with more or less interaction with source, but you already know that, plus I really love how a baxandall reacts in a 12AX7 feedback, it's ones of the options I would like to implement in my mixer, but for me silicon is acceptable (only discrete, I also have my mind problems) and I won't have this problem. In my project there is a 22pin slot with a HV rail for this kind of applications, far away from the original pins of the 51X, don't cry! so no DC-DC converter needed.
JS
In the other hand, as you seen the compensation with the output impedance, using a dual fader, where one would be used as fader and the other as compensation isn't an option? It would add a little complex in a much 'better' (with less interaction) and clever design I guess.
There are other options in passive eq, with more or less interaction with source, but you already know that, plus I really love how a baxandall reacts in a 12AX7 feedback, it's ones of the options I would like to implement in my mixer, but for me silicon is acceptable (only discrete, I also have my mind problems) and I won't have this problem. In my project there is a 22pin slot with a HV rail for this kind of applications, far away from the original pins of the 51X, don't cry! so no DC-DC converter needed.
JS