Is it possible to the Zstage with two sets of inputs? Most likely not worth it?

Anyone here have opinions if this unit is worth the cost?

Not sure if my system would benefit.  Vpi Scout, Black 2m cart, zp3, Parasound  Pre and amp….

Thanks
Doug

The ZStage is a small and simple (relatively purist) tube stage with some quite useful gain adjustment. 4-5 volts is enough for "gain riding," which I love for tuning a recording to better balance in my system: while keeping the same relative volume, adjusting the ZStage gain up, while turning the amp gain down, by pumping up the voltage from the ZStage, it increases body, lucidity, dynamics and bass. Or visa-versa, if the recording needs leaning down, adjusting the ZStage down, while adjusting the amp up, you can open things up and relax excess density and thickness to various degrees. But before that, a good baseline is important. Using this same basic theory, the ZStage  can be quite useful for gain matching between gear, tuning the whole system to sound, and perhaps leaving it alone after a preferred tonal/dynamic/lucidity balance is reached. But I keep going. From a good gain balance between gear, I then "gain ride" if needed, to optimize recordings.

Since the ZStage is designed to be pretty transparent, having simple signal and power paths, the sound variation from tubes is a pretty powerful, making tube rolling a relatively pure tuning tool. The impact from each tube's sound is clear. Without having other tubes to adjust tuning, you have to like the given tube sound, but you also have the purity of one tube only. That said, about any decent tube will sound good in the ZStage, but preferences might cause one to want to take advantage of tube experimentation.

Also, the bias switch makes each tube sort of like two tubes...one way pushing the tube harder and sounding more full and rich, and the other more neutral, also a pretty good tuning device for some recording imbalances. And one tube only, makes it easy to play around with tubes, with loads of variations in 12AU7 and 12AT7 types, straightforward and fun if you like tube rolling. One thing to mention, if you want lots of tube "coloring," this may not be what you are after. You can tune a ZStage to be more euphonic with juicier tubes, but to me the basic setup is more about relatively transparent voltage and harmonic tube tuning than an overtly "tubey" sound. You hear the tubes for sure, but without a lot of added colors.

This was a long time ago, so I don't know how he would feel about it now, but I was able to get Steve to put two inputs on mine. If I recall correctly, being quite serious about his design work, he was a little reluctant based on layout issues, including not having a lot of room for another switch in an intuitive place, and fitting another pair of RCAs. He ended up putting the channel switch on the back, likely the best place for it anyway sound wise, nearest the RCAs, and this was a totally acceptable solution for me, so we went for it.

I liked the Jupiter cap upgrade in mine. And based on my experience with cap bypassing and general upgrade work since, if I were not doing these things, I would want the Anniversary mods and stepped attenuator also. From my experience with similar work, if your system is resolving, I suspect these mods would transform the piece from very good, to great...At least by the way I hear things...

So yes, it could get costly. Can't possibly say if it would be worth it to another, but in my system, I suspect I would find it so if I did not already have a ZBIT and CSP3, both pretty seriously upgraded from a stock configuration.

I used my pre-Anniversary ZStage for years in my main system and liked it a lot. As I recall, the change was not "mind blowing," but a meaningful upgrade, another tube stage very nice for gain balancing, and probably more, I love "gain riding," especially with the lucidity of well implemented tubes...something I have used to fine-tune recordings every day, ever since I got the ZStage. And had I been able to get the Anniversary mods back then, I may well still have the ZStage in my main system. But back then I got seduced by a CSP3, and moved the ZStage to my other system. I have not gone into the ZStage to upgrade it, but thinking about it now, I will put that on the list! Then, a direct comparison with my fully tuned CSP3 will be really interesting.